Inst. Mechanik

73 Items

Recent Submissions
Design, analysis, and control of a cable-driven parallel platform with a pneumatic muscle active support

Zhao, Xingwei ; Zi, Bin ; Qian, Lu (2017)

The neck is an important part of the body that connects the head to the torso, supporting the weight and generating the movement of the head. In this paper, a cable-driven parallel platform with a pneumatic muscle active support (CPPPMS) is presented for imitating human necks, where cable actuators imitate neck muscles and a pneumatic muscle actuator imitates spinal muscles, respectively. Analy...

Non-linear investigation of an asymmetric disk brake model

Spelsberg-Korspeter, G. ; Hochlenert, Daniel ; Hagedorn, P. (2011)

Among design engineers, it is known that breaking symmetries of a brake rotor can help to prevent squeal. From a modelling point of view, in the literature brake squeal is almost exclusively treated using models with a symmetric brake rotor, which are capable of explaining the excitation mechanism but yield no insight into the relation between rotor asymmetry and stability. In previous work, it...

A mathematical model in three-dimensional piezoelectric continuum to predict non-linear responses of piezoceramic materials

Samal, M. K. ; Seshu, P. ; Wagner, Utz von ; Hagedorn, P. ; Dutta, B. K. ; Kushwaha, H. S. (2008)

It has been experimentally observed that the piezoceramic materials exhibit different types of non-linearities under different combinations of electrical and mechanical fields. When excited near resonance in the presence of weak electric fields, they exhibit typical non-linearities similar to a Duffing oscillator such as jump phenomena and the presence of superharmonics in the response spectra....

Aspects of Modeling Piezoelectric Active Thin-walled Structures

Marinković, Dragan ; Köppe, Heinz ; Gabbert, Ulrich (2009)

The objective of this article is to reconsider some important aspects of modeling piezoelectric active thin-walled structures. Hence, it is dealt here with thin-walled laminated structures involving piezoelectric patches. A recently developed shell type finite element is used for the purpose. The first aspect is adequate modeling of electric field within the piezoelectric patches polarized in t...

Grundlagen und Anwendbarkeit von Magneto-Adaptronischen Transducern (MATs) an ferromagnetischen Materialien zur aktiven Schall- und Schwingungsminderung

Glugla, Markus (2018)

Die magnetischen Eigenschaften von ferromagnetischen Materialien zeigen zwei Effekte, den Joule- und den Villari-Effekt. Der Joule-Effekt, auch bekannt als magnetostriktiver Effekt, beschreibt die Längen- und Volumenänderung eines ferromagnetischen Materials unter Einwirkung eines magnetischen Felds. Der inverse Vorgang, die Änderung des Magnetfelds eines ferromagnetischen Materials unter Einwi...

Zur Modellbildung und Analyse von bistabilen Energy-Harvesting-Systemen

Lentz, Lukas (2018)

The subject of the thesis is the modeling and the analysis of a bistable energy-harvesting system. The energy-harvesting system consists of a bimorph beam that is made from a ferromagnetic substructure and piezoceramic layers on top. The beam is attached to a rigid frame which can be attached to a host structure. On the frame two permanent magnets are mounted in such a way, that the restoring f...

A mesoscopic approach to diffusion phenomena in mixtures

Palumbo, Nunzia ; Papenfuss, Christina ; Rogolino, Patrizia (2005)

The mesoscopic concept is applied to the theory of mixtures. The aim is to investigate the diusion phenomenon from a mesoscopic point of view. The domain of the field quantities is extended by the set of mesoscopic variables, here the velocities of the components. Balance equations on this enlarged space are the equations of motion for the mesoscopic fields. Moreover, local distribution functio...

Thermodynamical Frameworks for Higher Grade Material Theories with Internal Variables or Additional Degrees of Freedom

Papenfuss, Christina ; Forest, Samuel (2006)

The objective of the present work is to compare several thermomechanical frameworks, taking into account the influence of strain gradient, internal variables, gradient of internal variables, and temperature gradient on the constitutive behavior of materials. In particular, the restrictions by the second law of thermodynamics are derived. The method of exploitation consists of two steps: an appl...

Mesoscopic Modeling for Continua with Pores: Application in Biological Soft Tissue

Weinberg, Kerstin ; Böhme, Thomas (2008)

In this work, the damage in biological soft tissue induced by bubble cavitation is investigated. A typical medical procedure with such damaging side effects is the kidney stone fragmentation by shock-wave lithotripsy. We start with a mesoscopic continuum model that allows the consideration of microstructural information within the macroscopic balance equations. An evolution equation for the tem...

Mesoscopic Modeling for Continua with Pores: Dynamic Void Growth in Viscoplastic Materials

Weinberg, Kerstin ; Böhme, Thomas (2008)

The temporal development of arbitrarily distributed voids in a viscoplastic material under different loading regimes is investigated. For this reason, we make use of a mesoscopic continuum model extending the classical space–time domain of continuum mechanics. This extended domain requires a reformulation of the classical balance equations as well as the consideration of additional constitutive...

Heterogeneity of material structure determines the stationary surface topography and friction

Li, Qiang ; Voll, Lars ; Starcevic, Jasminka ; Popov, Valentin L. (2018-09-21)

The character of surface roughness and the force of friction in the stationary state after a sufficiently long run-in process are of key importance for numerous applications, e.g. for friction between road and tire. In the present paper, we study theoretically and experimentally the asymptotic worn state of a bi-phasic material that is arbitrarily heterogeneous in the contact plane, but homogen...

Inverse analysis of cellulose by using the energy-based method and a rotational rheometer

Abali, Bilen Emek (2018-08-12)

Biological and polymer-type materials usually show a complicated deformation behavior. This behavior can be modeled by using a nonlinear material equation; however, the determination of coefficients in such a material equation is challenging. We exploit representation theorems in continuum mechanics and construct nonlinear material equations for cellulose in an oscillatory rheometer experiment....

Theoretical and experimental investigations of the bifurcation behavior of creep groan of automotive disk brakes

Zhao, Xingwei ; Gräbner, Nils ; Wagner, Utz von (2018)

There are several low frequency vibration phenomena which can be observed in automotive disk brakes. Creep groan is one of them provoking noise and structural vibrations of the car. In contrast to other vibration phenomena like brake squeal, creep groan is caused by the stick-slip-effect. A fundamental investigation of creep groan is proposed in this paper theoretically and experimentally with ...

Application of the mode-shape expansion based on model order reduction methods to a composite structure

Peredo Fuentes, Humberto (2017)

The application of different mode-shape expansion (MSE) methods to a CFRP based on model order reduction (MOR) and component mode synthesis (CMS) methods is evaluated combining the updated stiffness parameters of the full FE model obtained with a mix-numerical experimental technique (MNET) in a previous work. The eigenvectors and eigenfrequencies of the different MSE methods obtained are compar...

Application of the Craig-Bampton model order reduction method to a composite structure: MACco, COMAC, COMAC-S and eCOMAC

Peredo Fuentes, Humberto ; Zehn, Manfred (2016)

The Craig-Bampton model order reduction (CBMOR) method based on the Rayleigh-Ritz approach was applied in a previous work to simulate dynamic behavior of a composite structure (CFRP) using the modal assurance criteria (MAC) and cross orthogonality (XOR) to validate the correlation. Different coordinate modal assurance criteria are applied to complement and verify the eigenfrequencies and eigenv...

Application of the Craig-Bampton model order reduction method to a composite structure: MAC and XOR

Peredo Fuentes, Humberto ; Zehn, Manfred (2014)

The Craig-Bampton model order reduction (CBMOR) method based on the Rayleigh-Ritz approach is applied to dynamic behavior simulation of a composite structure in order to verify the method's feasibility and accuracy. The principle of this method is to represent a coupled component model based on the mass, damping and stiffness matrices. The methodology consists of a finite element model based on...

FEM-gestützte Analyse der linear-elastischen und hyperelastischen eigengravitierenden Erde unter dem Aspekt geometrischer und physikalischer Nichtlinearitäten

Lofink, Paul (2018)

Die vorliegende Arbeit befasst sich mit der Deformation der Erde aufgrund der Eigengravitation. Es werden zunächst kontinuumstheoretische Grundlagen vorgestellt. Dabei werden mechanische und thermodynamische Gesetze erläutert. Um das System aus Feldgleichungen zu schließen, werden nach der Methode von Coleman-Noll thermodynamisch-konsistente Materialgesetze hergeleitet. Das Eigengravitationsp...

Theoretical and experimental investigations of creep groan in automotive disk brakes

Zhao, Xingwei (2018)

Due to the increasing comfort claims of customers, the study on low frequency creep groan has been receiving increasing attention currently. This thesis forces on the study of the fundamental mechanism of creep groan theoretically and experimentally. In order to understand creep groan step by step, the design of test rigs concentrating on creep groan are presented. A test rig with an idealized...

Model reduction of components and assemblies made of composite materials as part of complex technical systems to simulate the overall dynamic behaviour

Peredo Fuentes, Humberto (2017)

The composite components and model order reduction (MOR) methods are widely used to improve the weight/strength ratio and the computational time respectively in different areas of the industry. The objective of this research is to evaluate the dynamic behaviour applying a MOR method in a composite component assembly. A new mixed numerical-experimental technique (MNET) is developed to obtain acc...

Neue MKS-FEM-Methode zur direkten Integration geometrischer und/oder materieller Nichtlinearitäten in die Simulation deformierbarer Mehrkörpersysteme

Nguyen, Viet Anh (2017)

Die vorliegende Arbeit präsentiert neue Möglichkeiten zur effizienten Behandlung geometrisch- und/oder physikalisch-nichtlinearer Probleme in der Dynamik deformierbarer Mehrkörpersystemen (MKS). Dabei werden beliebig große Starrkörperrotationen und nichtlineares Materialverhalten der Komponenten direkt in das Bewegungsgleichungssystem des Mehrkörpersystems einbezogen. Keine Co-Simulations- oder...