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# Prof. Dr.-Ing. Roland Platz

Wissenschaftliche Leitung

2.04

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Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• J. Lenz

Analysis of data uncertainty using the example of passive and active vibration isolation (Chapter 4.1.1)

In: Mastering Uncertainty in Mechanical Engineering. null (Tracts in Mechanical Engineering book series (STME)) pg. 119-123.

Berlin

• (2021)
• Maschinenbau und Mechatronik
• NACHHALTIG
Beitrag (Sammelband oder Tagungsband)

• C. Gehb
• T. Melz
• Roland Platz

Bayesian inference based parameter calibration for a mathematical model of a load-bearing structure (Chapter 4.1.2)

In: Mastering Uncertainty in Mechanical Engineering. null (Tracts in Mechanical Engineering book series (STME)) pg. 123-128.

Berlin

• (2021)
• Maschinenbau und Mechatronik
• NACHHALTIG
Beitrag (Sammelband oder Tagungsband)

• S. Kersting
• Roland Platz
• M. Kohler
• T. Melz

Data Uncertainty (Chapter 2.1)

In: Mastering Uncertainty in Mechanical Engineering. null (Tracts in Mechanical Engineering book series (STME)) pg. 31-34.

Berlin

• (2021)
• Maschinenbau und Mechatronik
• NACHHALTIG
Zeitschriftenartikel

• C. Ehrett
• D. Brown
• C. Kitchens
• X. Xu
• Roland Platz
• S. Atamturktur

Simultaneous Bayesian Calibration and Engineering Design With an Application to a Vibration Isolation System

In: Journal of Verification, Validation and Uncertainty Quantification vol. 6

• (2021)

#### Abstract anzeigen

Calibration of computer models and the use of those design models are two activities traditionally carried out separately. This paper generalizes existing Bayesian inverse analysis approaches for computer model calibration to present a methodology combining calibration and design in a unified Bayesian framework. This provides a computationally efficient means to undertake both tasks while quantifying all relevant sources of uncertainty. Specifically, compared with the traditional approach of design using parameter estimates from previously completed model calibration, this generalized framework inherently includes uncertainty from the calibration process in the design procedure. We demonstrate our approach to the design of a vibration isolation system. We also demonstrate how, when adaptive sampling of the phenomenon of interest is possible, the proposed framework may select new sampling locations using both available real observations and the computer model. This is especially useful when a misspecified model fails to reflect that the calibration parameter is functionally dependent upon the design inputs to be optimized.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• M. Schaeffner
• Roland Platz
• T. Melz

Active buckling control of compressively loaded beam-columns and trusses (Chapter 5.4.7)

In: Mastering Uncertainty in Mechanical Engineering. null (Tracts in Mechanical Engineering book series (STME)) pg. 343-347.

Berlin

• (2021)
• Maschinenbau und Mechatronik
• NACHHALTIG
Beitrag (Sammelband oder Tagungsband)

• C. Gehb
• Roland Platz
• T. Melz

Load redistribution via semi-active guidance elements in a kinematic structure (Chapter 5.4.8)

In: Mastering Uncertainty in Mechanical Engineering. null (Tracts in Mechanical Engineering book series (STME)) pg. 347-351.

Berlin

• (2021)
• Maschinenbau und Mechatronik
• NACHHALTIG
Beitrag (Sammelband oder Tagungsband)

• J. Lenz
• M. Schäffner
• Roland Platz
• T. Melz

Selection of an Adequate Model of a Piezo-Elastic Support for Structural Control in a Beam Truss Structure

In: Model Validation and Uncertainty Quantification, Volume 3. null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 41-49.

Cham

• (2020)

#### Abstract anzeigen

Axial and lateral loads of lightweight beam truss structures e.g. used in automotive engineering may lead to undesired structural vibration that can be reduced near a structural resonance frequency via resonant piezoelectric shunt-damping. In order to tune the electrical circuits to the desired structural resonance frequency within a model-based approach, an adequate mathematical model of the beam truss structure is required. Piezo-elastic truss supports with integrated piezoelectric stack transducers can transfer the axial and lateral forces and may be used for vibration attenuation of single beams or whole beam truss structures. For usage in a single beam test setup, the piezo-elastic support’s casing is clamped rigidly and is connected to the beam via a membrane-like spring element that allows for rotation as well as axial and lateral displacements of the beam. In this contribution, the piezo-elastic support is integrated into a two-dimensional beam truss structure comprising seven beams, where its casing is no longer clamped rigidly but is subject to axial, lateral and rotational displacements. Based on the previously verified and validated model of the single beam test setup, two different complex mathematical models of the piezo-elastic support integrated in the two-dimensional beam truss structure are derived in this contribution. The two mathematical models differ in their number of degrees of freedom for the piezo-elastic support as well as in the assumption of rigid or compliant casing. By comparing numerically and experimentally determined structural resonance frequencies and vibration amplitudes, the model that more adequately predicts the truss structure’s vibration behavior is selected on basis of the normalized root mean squared error. For future works, the more adequate model will be used to tune electrical circuits for resonant piezoelectric shunt-damping in a three-dimensional truss structure.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• R. Feldmann
• M. Schäffner
• C. Gehb
• Roland Platz
• T. Melz

Analyzing Propagation of Model Form Uncertainty for Different Suspension Strut Models

In: Model Validation and Uncertainty Quantification, Volume 3. null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 255-263.

Cham

• (2020)

#### Abstract anzeigen

Model form uncertainty often arises in structural engineering problems when simplifications and assumptions in the mathematical modelling process admit multiple possible models. It is well known that all models incorporate a model error that is captured by a discrepancy due to missing or incomplete physics in the mathematical model. As an example, this discrepancy can be modelled as a function based upon Gaussian processes and its confidence bounds can be seen as a measure of adequacy for the respective model. Assessment of model form uncertainty can be conducted by comparing the confidence bounds of competing discrepancy functions. In this paper, a modular active spring-damper system is considered that was designed to resemble a suspension strut as part of an aircraft landing gear and is excited by dynamic drop tests. In previous research about the suspension strut, different mathematical system models with respect to different linear and non-linear assumptions for damping and stiffness properties to describe the dynamic system behaviour of the suspension strut were compared by means of the confidence intervals of their discrepancy functions. The results indicated that the initial conditions used for exciting the system model were inadequate. The initial conditions themselves constitute a mathematical model, so that model form uncertainty inherent to the initial condition model can effect the system model. The propagation of model form uncertainty within the model will be analysed in this paper by considering two cases: In the first case, the system model is excited with an inadequate initial condition model, while in the second case, experimentally measured initial conditions will be employed that represent the true value except for measurement errors. The comparison of both shows how model form uncertainty propagates through the model chain from the initial condition model to the system model.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• C. Gehb
• Roland Platz
• T. Melz

BAYESIAN Inference Based Parameter Calibration of a Mechanical Load-Bearing Structure’s Mathematical Model

In: Model Validation and Uncertainty Quantification, Volume 3. null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 337-347.

Cham

• (2020)

#### Abstract anzeigen

• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Zeitschriftenartikel

• C. Gehb
• S. Atamturktur
• Roland Platz
• T. Melz

Bayesian Inference Based Parameter Calibration of the LuGre-Friction Model

In: Experimental Techniques vol. 44 pg. 369-382.

• (2020)

#### Abstract anzeigen

Load redistribution in smart load bearing mechanical structures can be used to reduce negative effects of damage or to prevent further damage if predefined load paths become unsuitable. Using controlled friction brakes in joints of kinematic links can be a suitable way to add dynamic functionality for desired load path redistribution. Therefore, adequate friction models are needed to predict the friction behavior. Possible models that can be used to model friction vary from simple static to complex dynamic models with increasing sophistication in the representation of friction phenomena. The LuGre-model is a widely used dynamic friction model for friction compensation in high precision control systems. It needs six parameters for describing the friction behavior. These parameters are coupled to an unmeasurable internal state variable, therefore, parameter identification is challenging. Conventionally, optimization algorithms are used to identify the LuGre-parameters deterministically. In this paper, the parameter identification and calibration is formulated to achieve model prediction that is statistically consistent with the experimental data. By use of the R2 sensitivity analysis, the most influential parameters are selected for calibration. Subsequently, the Bayesian inference based calibration procedure using experimental data is performed. Uncertainty represented in former wide parameter ranges can be reduced and, thus, model prediction accuracy can be increased.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• S. Mallapur
• Roland Platz

Uncertainty quantification in the mathematical modelling of a suspension strut using Bayesian inference

In: Mechanical Systems and Signal Processing vol. 118 pg. 158-170.

• (2019)

#### Abstract anzeigen

In the field of structural engineering, mathematical models are utilized to predict the dynamic response of systems such as a suspension strut under different boundary and loading conditions. However, different mathematical models exist based on their governing functional relations between the model input and state output parameters. For example, the spring-damper component of a suspension strut is considered. Its mathematical model can be represented by linear, nonlinear, axiomatic or empiric relations resulting in different vibrational behaviour. The uncertainty that arises in the prediction of the dynamic response from the resulting different approaches in mathematical modelling may be quantified with Bayesian inference approach especially when the system is under structural risk and failure assessment. As the dynamic output of the suspension strut, the spring-damper compression and the spring-damper forces as well as the ground impact force are considered in this contribution that are taken as the criteria for uncertainty evaluation due to different functional relations of models. The system is excited by initial velocities that depend on a drop height of the suspension strut during drop tests. The suspension strut is a multi-variable system with the payload and the drop height as its varied input variables in this investigation. As a new approach, the authors present a way to adequately compare different models based on axiomatic or empiric assumptions of functional relations using the posterior probabilities of competing mathematical models. The posterior probabilities of different mathematical models are used as a metric to evaluate the model uncertainty of a suspension strut system with similar specifications as actual suspension struts in automotive or aerospace applications for decision making in early design stage. The posterior probabilities are estimated from the likelihood function, which is estimated from the cartesian vector distances between the predicted output and the experimental output.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• C. Gehb
• Roland Platz
• T. Melz

Two control strategies for semi-active load path redistribution in a load-bearing structure

In: Mechanical Systems and Signal Processing vol. 118 pg. 195-208.

• (2019)

#### Abstract anzeigen

In this paper, a two mass oscillator, a translatoric moving mass connected to a rigid beam by a spring-damper system, is used to numerically and experimentally investigate the capability of load path redistribution due to controlled semi-active guidance elements with friction brakes. The mathematical friction model will be derived by the LuGre approach. The rigid beam is embedded on two supports and is initially aligned with evenly distributed loads in beam and supports by the same stiffness condition. With the semi-active auxiliary guidance elements it is possible to provide additional forces to relieve one of the beam’s supports. Two control strategies are designed and tested to induce additional forces in the auxiliary guidance elements to bypass a proportion of loading away from the spring-damper system towards the now kinetic auxiliary guidance elements. The control strategies I and II depend on the different control inputs: I beam misalignment and II desired reaction force ratio in the supports. The beam’s misalignment and the supports’ reaction forces are calculated numerically and measured experimentally for varying stiffness parameters of the supports and are compared with and without semi-active auxiliary kinematic guidance elements. The structure’s moving mass is loaded with a force according to a step-function. Thus, undesired misalignment caused by varying stiffness as well as undesired load distribution in the structure’s supports can be reduced by redistributing load between the supports during operation.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Zeitschriftenartikel

• M. Kohler
• A. Krzyżak
• S. Mallapur
• Roland Platz

Uncertainty Quantification in Case of Imperfect Models: A Non‐Bayesian Approach

In: Scandinavian Journal of Statistics vol. 45 pg. 729-752.

• (2018)

#### Abstract anzeigen

The starting point in uncertainty quantification is a stochastic model, which is fitted to a technical system in a suitable way, and prediction of uncertainty is carried out within this stochastic model. In any application, such a model will not be perfect, so any uncertainty quantification from such a model has to take into account the inadequacy of the model. In this paper, we rigorously show how the observed data of the technical system can be used to build a conservative non-asymptotic confidence interval on quantiles related to experiments with the technical system. The construction of this confidence interval is based on concentration inequalities and order statistics. An asymptotic bound on the length of this confidence interval is presented. Here we assume that engineers use more and more of their knowledge to build models with order of errors bounded by urn:x-wiley:sjos:media:sjos12317:sjos12317-math-0001. The results are illustrated by applying the newly proposed approach to real and simulated data.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• M. Schäffner
• Roland Platz

Gain-Scheduled H∞ Buckling control of a Circular Beam-Column Subject to Time-Varying Axial Loads

In: Smart Materials and Structures vol. 27 pg. 065009.

• (2018)

#### Abstract anzeigen

Smart Materials and Structures Paper Gain-scheduled ${{\mathscr{H}}}_{\infty }$ buckling control of a circular beam-column subject to time-varying axial loads Maximilian Schaeffner1 and Roland Platz2 Published 3 May 2018 • © 2018 IOP Publishing Ltd Smart Materials and Structures, Volume 27, Number 6 Citation Maximilian Schaeffner and Roland Platz 2018 Smart Mater. Struct. 27 065009 99 Total downloads 6 6 total citations on Dimensions. Turn on MathJax Get permission to re-use this article Share this article Share this content via email Share on Facebook Share on Twitter Share on Google+ Share on Mendeley Hide article information Author affiliations 1 Technische Universität Darmstadt, System Reliability, Adaptronics and Machine Acoustics SAM, Magdalenenstraße 4, D-64289 Darmstadt, Germany 2 Fraunhofer Institute for Structural Durability and System Reliability LBF, Bartningstraße 47, D-64289 Darmstadt, Germany ORCID iDs Maximilian Schaeffner https://orcid.org/0000-0002-0957-7725 Dates Received 12 January 2018 Accepted 13 March 2018 Published 3 May 2018 Check for updates using Crossmark Peer review information Method: Single-anonymous Screened for originality? Yes DOI https://doi.org/10.1088/1361-665X/aab63a [Titel anhand dieser DOI in Citavi-Projekt übernehmen] Buy this article in print Journal RSS Sign up for new issue notifications Create citation alert Abstract For slender beam-columns loaded by axial compressive forces, active buckling control provides a possibility to increase the maximum bearable axial load above that of a purely passive structure. In this paper, an approach for gain-scheduled ${{\mathscr{H}}}_{\infty }$ buckling control of a slender beam-column with circular cross-section subject to time-varying axial loads is investigated experimentally. Piezo-elastic supports with integrated piezoelectric stack actuators at the beam-column ends allow an active stabilization in arbitrary lateral directions. The axial loads on the beam-column influence its lateral dynamic behavior and, eventually, cause the beam-column to buckle. A reduced modal model of the beam-column subject to axial loads including the dynamics of the electrical components is set up and calibrated with experimental data. Particularly, the linear parameter-varying open-loop plant is used to design a model-based gain-scheduled ${{\mathscr{H}}}_{\infty }$ buckling control that is implemented in an experimental test setup. The beam-column is loaded by ramp- and step-shaped time-varying axial compressive loads that result in a lateral deformation of the beam-column due to imperfections, such as predeformation, eccentric loading or clamping moments. The lateral deformations and the maximum bearable loads of the beam-column are analyzed and compared for the beam-column with and without gain-scheduled ${{\mathscr{H}}}_{\infty }$ buckling control or, respectively, active and passive configuration. With the proposed gain-scheduled ${{\mathscr{H}}}_{\infty }$ buckling control it is possible to increase the maximum bearable load of the active beam-column by 19% for ramp-shaped axial loads and to significantly reduce the beam-column deformations for step-shaped axial loads compared to the passive structure.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• D. Mayer
• G. Stevens

Approach in Uncertainty Quantification to Predict the Vibration Control Performance of Tuned Absorbers in Early Design Stage (Paper No. 262)

• (2018)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• B. Götz
• Roland Platz
• T. Melz

Global Load Path Adaption in a Simple Kinematic Load-Bearing Structure to Compensate Uncertainty of Misalignment Due to Changing Stiffness Conditions of the Structure's Supports

In: Proceedings of the 35th IMAC, a Conference and Exposition on Structural Dynamics 2017 (30 Jan - 2 Feb, 2017; Garden Grove, CA, USA). null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 133-144.

Cham

• (2017)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• B. Götz
• Roland Platz
• T. Melz

Lateral Vibration Attenuation of a Beam with Piezo-Elastic Supports Subject to Varying Axial Tensile and Compressive Loads

In: Proceedings of the 35th IMAC, a Conference and Exposition on Structural Dynamics 2017 (30 Jan - 2 Feb, 2017; Garden Grove, CA, USA). null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 1-8.

Cham

• (2017)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• B. Götz
• T. Melz

Approach to Evaluate and to Compare Basic Structural Design Concepts of Landing Gears in Early Stage of Development Under Uncertainty

In: Model Validation and Uncertainty Quantification, Volume 3. (IMAC-XXXIV Conference and Exposition on Structural Dynamics; January 25-28, 2016; Orlando, FL, USA) (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 167-175.

Cham

• (2016)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• C. Melzer

Uncertainty quantification for decision making in early design phase for passive and active vibration isolation

pg. 4501-4513.

• (2016)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• S. Mallapur
• Roland Platz

Description and evaluation of uncertainty in the early development phase of a beam-column system subjected to passive and active buckling control

pg. 269-280.

Oldenbourg

• (2016)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Zeitschriftenartikel

• M. Schaeffner
• B. Götz
• Roland Platz

Active buckling control of a beam-column with circular cross-section using piezo-elastic supports and integral LQR control

In: Smart Materials and Structures vol. 25

• (2016)

#### Abstract anzeigen

Buckling of slender beam-columns subject to axial compressive loads represents a critical design constraint for light-weight structures. Active buckling control provides a possibility to stabilize slender beam-columns by active lateral forces or bending moments. In this paper, the potential of active buckling control of an axially loaded beam-column with circular solid cross-section by piezo-elastic supports is investigated experimentally. In the piezo-elastic supports, lateral forces of piezoelectric stack actuators are transformed into bending moments acting in arbitrary directions at the beam-column ends. A mathematical model of the axially loaded beam-column is derived to design an integral linear quadratic regulator (LQR) that stabilizes the system. The effectiveness of the stabilization concept is investigated in an experimental test setup and compared with the uncontrolled system. With the proposed active buckling control it is possible to stabilize the beam-column in arbitrary lateral direction for axial loads up to the theoretical critical buckling load of the system.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Patent

• M. Schäffner
• Roland Platz
• S. Ondoua
• T. Melz
• B. Götz
• C. Gehb
• G. Enss

• 19.11.2015 (2015)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• S. Ochs
• K. Pitz
• T. Melz
• Roland Platz

Quantitative Description and assessment of uncertainty for a load-bearing system

In: Tagungsband zur 27. VDI-Fachtagung Technische Zuverlässigkeit TTZ 2015. null (VDI-Berichte) pg. 29-44.

• (2015)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• G. Enss

Comparison of Uncertainty in Passive and Active Vibration Isolation

In: Model Validation and Uncertainty Quantification, Volume 3. null (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 15-25.

Cham

• (2015)

#### Abstract anzeigen

In this contribution, the authors discuss a clear and comprehensive way to deepen the understanding about the comparison of parametric uncertainty for early passive and active vibration isolation design in an adequate probabilistic way. A simple mathematical one degree of freedom linear model of an automobile’s suspension leg, excited by harmonic base point stroke and subject to passive and active vibration isolation purpose is used as an example study for uncertainty comparison. The model’s parameters are chassis mass, suspensions leg’s damping and stiffness for passive vibration isolation, and an additional gain factor for velocity feedback control when active vibration isolation is assumed. Assuming the parameters to be normally distributed, they are non-deterministic input for Monte Carlo-Simulations to investigate the dynamic vibrational response due the deterministic excitation. The model parameters are assumed to vary according plausible assumptions from literature and own works. Taking into account three different damping levels for each passive and active vibration isolation approach, the authors investigate the numerically simulated varying dynamical output from the model’s dynamic transfer function in six case studies in frequency and time domain. The cases for the output in frequency domain are (i) varying maximum vibration amplitudes at damped resonance frequencies for different passive and active damping levels, (ii) varying vibration amplitudes at the undamped resonance frequency, (iii) varying isolation frequency, (iv) varying amplitudes at the excitation frequency beyond the passive system’s fixed isolation frequency, and (v) vibration amplitudes for −15 dB isolation attenuation. In time domain, case (vi) takes a closer look at the varying decaying time until steady state vibration is reached.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• B. Götz
• M. Schäffner
• Roland Platz
• T. Melz

Model verification and validation of a piezo-elastic support for passive and active structural control of beams with circular cross-section

pg. 67-77.

• (2015)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• G. Enss
• S. Ondoua
• T. Melz

Active stabilization of a slender beam-column under static axial loading and estimated uncertainty in actuator properties

pg. 235-245.

• (2014)

#### Abstract anzeigen

Buckling of load-carrying beam-columns is a severe failure scenario in light-weight structures. The authors present an approach to actively stabilize a slender beam-column under static axial load to prevent it from buckling in its first buckling mode. For that, controlled active counteracting forces are applied by two piezoelectric stack actuators near the column's fixed base, achieving a 40% higher axial critical load and leaving most of the column's surface free from actuation devices. However, uncertain actuator properties due to tolerances in characteristic maximum free stroke and blocking force capability have an influence on the active stabilization. This uncertainty and its effect on active buckling control is investigated by numerical simulation, based on experimental tests to determine the actual maximum free stroke and blocking force for several piezoelectric stack actuators. The simulation shows that the success of active buckling control depends on the actuator's variation in its maximum free stroke and blocking force capability.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• Roland Platz

Statistical approach for active buckling control with uncertainty

In: Topics in Modal Analysis I, Volume 7. (Proceedings of IMAC–XXXII A Conference and Exposition on Structural Dynamics; Feb. 3-6, 2014; Orlando, FL, USA) (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 291-297.

Cham

• (2014)

#### Abstract anzeigen

Buckling of load-carrying column structures is an important failure scenario in light-weight structures as it may result in the collapse of the entire structure. If the actual loading is unknown, stability becomes uncertain. To investigate uncertainty, a critically loaded beam-column, subject to buckling, clamped at the base and pinned at the upper end is considered, since it is highly sensitive to small changes in loading. To control the uncertainty of failure due to buckling, active forces are applied with two piezoelectric stack actuators arranged in opposing directions near the beam-column’s base to prevent it from buckling. In this paper, active buckling control is investigated experimentally. A mathematical model of the beam-column is built and a model based Linear Quadratic Regulator (LQR) is designed to stabilize the system. The controller is implemented on the experimental test setup and a statistically relevant number of experiments is conducted to prove the effect of active stabilization. It is found that the load bearing capacity of the beam-column could be increased by more than 40% for the experimental test setup using different controller parameters for three ranges of axial loading.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• S. Ondoua
• G. Enss
• T. Melz

Approach to Evaluate Uncertainty in Passive and Active Vibration Reduction

In: Topics in Modal Analysis I, Volume 7. (Proceedings of IMAC–XXXII A Conference and Exposition on Structural Dynamics; Feb. 3-6, 2014; Orlando, FL, USA) (Conference Proceedings of the Society for Experimental Mechanics Series) pg. 345-352.

Cham

• (2014)

#### Abstract anzeigen

Uncertainty is an important design constraint when configuring a dynamic mechanical system that is subject to passive or active vibration reduction. Uncertainty can be divided into the categories unknown, estimated and stochastic uncertainty depending on the amount of information, e.g. of the principal mechanical parameter’s deviation in inertia, energy dissipation, compliance and today more and more with active energy feeding to enhance damping. In this paper, these uncertainty categories as well as solutions for uncertainty control in the early design phase will be described and evaluated analytically in a simple but consistent and transparent way on the basis of a mathematical dynamic linear model. The model is a one degree of freedom mass-damper-spring system representing a suspension leg supporting a vehicle’s chassis that is subject to passive and active damping. The amplitude and phase responses in frequency domain are shown analytically in case studies for different assumptions of the effective uncertainty. Amongst others, sample tests are conducted by Monte Carlo Simulations when stochastic uncertainty is considered. The uncertainty examinations on vibration reduction for the selected dynamical model show promising results indicating the predominance of active damping vs. passive damping statistically.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• M. Schäffner
• G. Enss
• Roland Platz

Influence of uncertain support boundary conditions on the buckling load of an axially loaded beam-column

pg. 4675–4686.

• (2014)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• G. Enss
• B. Götz
• M. Kohler
• A. Krzyżak
• Roland Platz

Nonparametric estimation of a maximum of quantiles

In: Electronic Journal of Statistics vol. 8 pg. 3176 - 3192.

• (2014)

#### Abstract anzeigen

A simulation model of a complex system is considered, for which the outcome is described by m(p,X), where p is a parameter of the system, X is a random input of the system and m is a real-valued function. The maximum (with respect to p) of the quantiles of m(p,X) is estimated. The quantiles of m(p,X) of a given level are estimated for various values of p from an order statistic of values m(pi,Xi) where X,X1,X2,… are independent and identically distributed and where pi is close to p, and the maximal quantile is estimated by the maximum of these quantile estimates. Under assumptions on the smoothness of the function describing the dependency of the values of the quantiles on the parameter p the rate of convergence of this estimate is analyzed. The finite sample size behavior of the estimate is illustrated by simulated data and by applying it in a simulation model of a real mechanical system.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• Roland Platz
• H. Hanselka

Mathematical modelling of postbuckling in a slender beam column for active stabilisation control with respect to uncertainty

In: Active and Passive Smart Structures and Integrated Systems 2012 (12-15 March 2012; San Diego, CA, USA). null (Proceedings of SPIE) pg. 834119.

Bellingham, WA, USA

• (2012)

#### Abstract anzeigen

• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• H. Hanselka
• P. Groche
• Roland Platz

Uncertainty in Mechanical Engineering

• (2012)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• T. Eifler
• G. Enss
• M. Haydn
• L. Mosch
• Roland Platz
• H. Hanselka

Approach for a Consistent Description of Uncertainty in Process Chains of Load Carrying Mechanical Systems

In: Applied Mechanics and Materials vol. 104 pg. 133-144.

• (2011)

#### Abstract anzeigen

Uncertainty in load carrying systems e.g. may result from geometric and material deviations in production and assembly of its parts. In usage, this uncertainty may lead to not completely known loads and strength which may lead to severe failure of parts or the entire system. Therefore, an analysis of uncertainty is recommended. In this paper, uncertainty is assumed to occur in processes and an approach is presented to describe uncertainty consistently within processes and process chains. This description is then applied to an example which considers uncertainty in the production and assembly processes of a simple tripod system and its effect on the resulting load distribution in its legs. The consistent description allows the detection of uncertainties and, furthermore, to display uncertainty propagation in process chains for load carrying systems.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• S. Ondoua
• Roland Platz
• J. Nuffer
• H. Hanselka

A study of uncertainties in active load carrying systems due to scatter in specifications of piezoelectric actuators

pg. 2114-2120.

London

• (2011)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Zeitschriftenartikel

• J. Koenen
• G. Enss
• S. Ondoua
• Roland Platz
• H. Hanselka

Evaluation and Control of Uncertainty in Using an Active Column System

In: Applied Mechanics and Materials vol. 104 pg. 187-195.

• (2011)

#### Abstract anzeigen

• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• Roland Platz
• H. Hanselka

Parameter study on an actively stabilised beam column

pg. 17-25.

• (2011)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• T. Eifler
• M. Haydn
• L. Mosch
• Roland Platz
• H. Hanselka

Prozessmodell zur systematischen Beschreibung und Verkettung von Unsicherheit (Process model for systematic description and linking uncertainty) . Poster

• (2011)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• J. Koenen
• Roland Platz
• H. Hanselka

General approach and possibility to evaluate uncertainty in estimating loads acting on a beam (Paper No. 25)

• (2011)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• Roland Platz
• H. Hanselka

A survey on uncertainty in the control of an active column critical to buckling (Paper No. 17)

• (2011)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• R. Engelhard
• G. Enss
• J. Koenen
• A. Sichau
• Roland Platz
• H. Kloberdanz
• H. Birkhofer
• H. Hanselka

A Model to Categorise Uncertainty in Load-Carrying Systems

pg. 53-64.

• (2010)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• G. Enss
• Roland Platz
• H. Hanselka

An Approach to Control the Stability in an Active Load-Carrying Beam-Column by One Single Piezoelectric Stack Actuator

pg. 535-546.

• (2010)

#### Abstract anzeigen

Euler buckling of column structures is an important design constraint in slender light-weight structures as it may result in the collapse of an entire structure. Thus, uncertainties in the usage of technical products, that result from unforeseen incidents or misuse, shall be identified, assessed and controlled. The main objective of this research is to develop and validate a concept to stabilise a column structure by the use of a lateral active force, induced by a piezoelectric stack actuator. A slender flat beam-column, built in vertically at the base, pinned at the upper end and loaded by an axial compressive force equal to its buckling load is examined numerically and experimentally. The active stabilisation is based on the fact that the initial minimal deflection will be superimposed with the deflection, caused by an actively controlled actively controlled counteracting force. This leads the structure into its approximate second bending deflection mode. With the concept shown, a simple beam-column critical to buckling is stabilised on demand.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• H. Hanselka
• Roland Platz

Ansätze und Maßnahmen zur Beherrschung von Unsicherheit in lasttragenden Systemen des Maschinenbaus . Controlling uncertainties in load carrying systems

In: Konstruktion (Zeitschrift für Produktentwicklung und Ingenieur-Werkstoffe) pg. 55-62.

• (2010)

#### Abstract anzeigen

In diesem Beitrag werden neue Ansätze zur Beherrschung von Unsicherheiten in lasttragenden Systemen vorgestellt. Werden Unsicherheiten beherrscht, können z. B. Sicherheitsbeiwerte zwischen Beanspruchbarkeit und Beanspruchung minimiert, Überdimensionierung vermieden, Ressourcen geschont, Einsatzbereiche erweitert und damit wirtschaftlicher Vorteil ermöglicht werden. Um diese Ziele zu erreichen, werden im seit Anfang 2009 bestehenden und von der Deutschen Forschungsgemeinschaft DFG geförderten Sonderforschungsbereich SFB 805 zunächst bekannte Methoden und Technologien zur Entwicklung, Produktion und Nutzung bis zur Wiederverwendung lasttragender Systeme hinsichtlich ihres Unsicherheitspotenzials untersucht. Auf dieser Basis werden dann die Unsicherheiten systematisch beschrieben und beurteilt, um sie schließlich zu beherrschen. This paper shows a new approach for controlling uncertainties in load carrying systems in mechanical engineering. By controlling uncertainties, for example, safety margins between mechanical loading and strength will be lowered, oversizing will be reduced, resources will be preserved, range of application will be widened and economic advantages will be achieved. To reach these goals, the new german collaborative research centre (SFB 805), funded by the Deutsche Forschungsgemeinschaft DFG and started in January 2009, examines in the first step the potential of uncertainties of well known methods and technologies to develop, to fabricate and to use as well as to reuse load carrying systems. On this basis and in the second step, uncertainties will be described and evaluated systematically to, eventually, control them.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• S. Ondoua
• K. Habermehl
• T. Bedarff
• T. Hauer
• S. Schmitt
• H. Hanselka

Approach to validate the influences of uncertainties in manufacturing on using load-carrying structures

pg. 5319-5333.

• (2010)

#### Abstract anzeigen

This paper gives an example of a new approach to display systematically uncertainties within the processchain to manufacture, to assemble and to use load-carrying structures to, eventually, control them in the future. By controlling uncertainties, safety margins between external loading and internal strength of a load carrying structure could be lowered, oversizing will be reduced, resources will be preserved, range of application will be widened and economic advantages will be achieved. In this work, the influences of uncertainties in manufacturing as well as assembling processes on the usage processes with respect to load distribution in a simple tripod is examined. If equal load distribution is desired, this equality highly depends on the quality of drilling holes for a leg connecting device. The holes vary in diameters, so the legs may be assembled differently. It will be shown exemplary, how deviations due to manufacturing may change the load distribution. Monte Carlo Simulation and real experiments on a simple tripod are conducted for validation.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• S. Ondoua
• Roland Platz
• J. Nuffer
• H. Hanselka

Uncertainties in active stabilization of buckling

University Park, PA; Red Hook, NY

• (2010)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• J. Koenen
• Roland Platz
• H. Hanselka

A survey to control uncertainties by comprehensive monitoring of load-carrying structures

In: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2010. null (SPIE Proceedings) pg. 76471R1–76471R9.

• (2010)

#### Abstract anzeigen

This paper gives a general view on some aspects of the influence of uncertainty in model-based monitoring of loadcarrying structures. The advantages and relevance of monitoring for the prediction of reliability will be clarified and the difference between uncertainty and reliability is discussed. Solving inverse Problems is a particular challenge in monitoring systems. Therefore, different categories of inverse problems are discussed. A generally valid extended difference equation, which describes the transfer behavior of the structure, will be derived as the basis for digital signal processing of model-based monitoring. This equation also considers changes in the structures dynamic properties, e.g due to damage or temperature. With this equation, the influence of uncertainty due to measurement noise to the functionability of monitoring is discussed and some possibilities are shown to control this uncertainty when determining ideal sensor-positions for monitoring.
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• E. Janssen

Mechatronische Stabilisierung knickgefährdeter Stäbe in lasttragenden Systemen des Maschinenbaus (Mechatronic stabilisation of beams critical to buckling)

pg. 323-328.

• (2009)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• M. Matthias
• Roland Platz
• J. Bös

Lärm- und Schwingungsminderung im Schiffbau durch adaptronische/mechatronische Lösungsansätze (Acoustic and vibration reduction in ship building with mechatronic solutions)

pg. 384-399.

• (2009)

#### Abstract anzeigen

Maßnahmen zur technischen Lärm- und Schwingungsminderung basieren idealerweise auf der Vermeidung der Entstehung, der Verringerung der Abstrahlung oder der Beeinflussung der Ausbreitung und Übertragung von Vibrationen und (Körper-) Schall am oder möglichst nahe dem Entstehungsort sowie an Koppelstellen. Die Technologie der Adaptronik/Mechatronik verfolgt dazu den Ansatz, an entsprechenden Stellen (z.B. Lagerstellen, Verbindungselemente, schwingende Flächen) eine in Frequenz, Phase und Amplitude angepasste Kraft derart einzuleiten, dass sie die störenden Schwingungen destruktiv überlagert und somit eine Schwingungsreduktion erzielt wird. Die erreichbare Schwingungsreduktion und der dafür notwendige Aufwand (Entwicklungs- und Systemkosten) hängen dabei stark von der jeweiligen Zielanwendung ab. Anhand von unterschiedlichen Beispielen werden in diesem Beitrag das Potenzial und die Einsatzmöglichkeiten dieser Technologie für schiffbauliche Anwendungen dargestellt. Technical measures for noise and vibration reduction are usually based on the reduction of vibration generation, of sound radiation, or of the transmission of vibrations, air-borne, and structure-borne sound at (or as closely as possible to) the source, as well as at coupling points. The technology of adaptronics/mechatronics (i.e., smart structure technology) applies the concept of using additional forces that are adjusted with respect to frequency, phase, and amplitude at appropriate locations (e.g., bearings, fasteners, vibrating surfaces) in such a way that they counteract the unwanted vibrations in order to significantly reduce the overall vibrations. The achievable vibration reduction and the required expenses (e.g., development and system costs) depend strongly on the particular target application. This paper demonstrates the potential and possibilities of this technology for ship building applications.
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• D. Mayer
• J. Nuffer
• M. Thomaier
• K. Wolf

FMEA for qualitative measurement of the reliability of an active interface for vibration reduction in passenger cars

In: Proceedings der 23. Tagung Technische Zuverlässigkeit TTZ 2007. null (VDI-Bericht) pg. 317-328.

• (2007)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• R. Markert
• H. Hanselka

Modellgestützte Diagnose von Unwuchten und Wellenrissen in Rotorsystemen (Model based diagnose of unbalances and shaft cracks in rotor systems)

In: VDI-Schwingungstagung 2007: Schwingungsüberwachung und Diagnose von Maschinen. null (VDI-Berichte) pg. 205-223.

Düsseldorf

• (2007)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Zeitschriftenartikel

• Roland Platz
• A. Büter
• D. Mayer
• H. Hanselka

Schadensüberwachung mit Wandlermaterialien . Health Monitoring with Smart Materials

In: Thema Forschung (Technische Universität Darmstadt) pg. 20-27.

• (2006)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• A. Sekhar
• Roland Platz
• R. Markert

Health Monitoring and Crack Identifikation in a Rotor System

pg. 217-225.

Monza

• (2006)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Buch (Monographie)

• Roland Platz

Untersuchungen zur modellgestützten Diagnose von Unwuchten und Wellenrissen in Rotorsystemen . Dissertation

In: Fortschrittberichte VDI : Reihe 11, Schwingungstechnik vol. Nr. 325

VDI-Verlag Düsseldorf

• (2004)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• R. Markert

Untersuchungen zur Rißidentifikation in Rotoren

pg. 173-181.

Braunschweig

• (2003)
• TSZ Weißenburg
• Maschinenbau und Mechatronik
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• R. Markert
• J. Jayesh
• A. Sekhar

Model Based Unbalance and Fatigue Crack Identification in Rotor Systems

pg. 41.

• (2002)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• A. Sekhar
• Roland Platz
• R. Markert

Model based crack identification and monitoring in a rotor system passing the critical speed

pg. 877-884.

• (2002)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• Roland Platz
• R. Markert

Fault Models for On-line Identification of Malfunctions in Rotor Systems

pg. 435-446.

• (2001)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Beitrag (Sammelband oder Tagungsband)

• R. Markert
• Roland Platz
• M. Seidler

Model Based Fault Identification in Rotor Systems by Least Squares Fitting

pg. 901-907.

• (2000)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL
Hochschulschrift

• Roland Platz

Ermittlung des Dynamischen Verhaltens eines Verkehrsflugzeug-Fußbodens im Hinblick auf die Reduzierung von Schallabstrahlung in die Kabine . Masterarbeit in Kooperation mit Airbus Industries in Hamburg

Technische Universität Berlin Berlin

• 1998 (1998)
• Maschinenbau und Mechatronik
• TSZ Weißenburg
• DIGITAL

### Kernkompetenzen

• Bewegungsdynamik und Konstruktion
• Maschinen- und Strukturdynamik, Rotordynamik
• Schwingungstechnik, Experimentelle Modalanalyse
• Mathematische Modellierung, numerische Simulation, experimenteller Test
• Model Verifikation und Validierung, probabilistische und nicht-probabilistische Quantifizierung der Unsicherheit
• Aktive/adaptive Zustandskontrolle, StructuralHealth Monitoring und Kontrolle in mechatronischen dynamischen Systemen.
• Quantifizierung Systemzuverlässigkeit und Unsicherheit in früher Entwicklungsphase
• Lehre und Betreuung/Beratung Studierender

# Universität

• 2004 Dr.-Ing., Rotordynamik, ehem. Fachbereich Mechanik, TU Darmstadt
• 1998 Dipl.-Ing.,Maschinenbau, Technische Universität Berlin

# Beruf/Tätigkeiten

• 2019 – 2021 Visiting Scholar for Structural Dynamics and Uncertainty Quantification, Architectural Engineering, College of Engineering, Penn State University, State College
• 2017 – 2019 Forschungsgruppenleiter, Systemzuverlässigkeit Future Mobility, Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF, Darmstadt
• 2008 – 2019 Wissenschaftlicher Fachgruppenleiter und Geschäftsführer sowie Teilprojektleiter im SFB 805 „Beherrschung von Unsicherheit in lasttragenden Systemen des Maschinenbaus“, Fraunhofer LBF, Darmstadt
• 2016 – 2017 Adjunct Professor, Department of Civil Engineering, College of Engineering & Science, Clemson University, Clemson
• 2004 – 2008 Wissenschaftlicher Mitarbeiter, Geschäftsführung des Forschungsschwerpunkts für Funktionale Werkstoffe am Fachgebiet Systemzuverlässigkeit, Adaptronik und Maschinenakustik SAM an der sowie am Fraunhofer LBF
• 1998 – 2004 Wissenschaftlicher Mitarbeiter, Arbeitsgruppe Rotordynamik, ehem. Fachbereich Mechanik, Technische Universität Darmstadt
• 1997 – 1998 Structural Engineer/Stress Analyst, Boeing Commercial Airplane Group, Seattle