Inst. Mechanik

92 Items

Recent Submissions
Wear Analysis of a Heterogeneous Annular Cylinder

Li, Qiang ; Forsbach, Fabian ; Schuster, Maximilian ; Pielsticker, Daniel ; Popov, Valentin L. (2018-03-18)

Wear of a cylindrical punch composed by two different materials alternatively distributed in annular forms is studied with the method of dimensionality reduction (MDR). The changes in surface topography and pressure distribution during the wear process is obtained and validated by the boundary element method (BEM). The pressure in each annular ring approaches a constant in a stationary state wh...

Thermodynamik der deformierbaren Festkörper unter Einfluss des Elektromagnetismus und die numerische Berechnung multiphysikalischer Prozesse

Abali, Bilen Emek (2019)

Die mathematische Beschreibung und zugehörige Simulation deformierbarer Festkörper unter mechanischer, thermischer und elektromagnetischer Belastung werden dargestellt. Ein solches multiphysikalisches System wird durch Bilanzgleichungen im Verbund mit konstitutiven Gleichungen berechenbar. Die Bilanzgleichungen inklusive Elektromagnetismus werden diskutiert und motiviert. Die konstitutiven Glei...

In Silico Optimization of Femoral Fixator Position and Configuration by Parametric CAD Model

Korunovic, Nikola ; Marinković, Dragan ; Trajanovic, Miroslav ; Zehn, Manfred ; Mitkovic, Milorad ; Affatato, Saverio (2019-07-22)

Structural analysis, based on the finite element method, and structural optimization, can help surgery planning or decrease the probability of fixator failure during bone healing. Structural optimization implies the creation of many finite element model instances, usually built using a computer-aided design (CAD) model of the bone-fixator assembly. The three most important features of such CAD ...

Dealing with Nap-Core Sandwich Composites: How to Predict the Effect of Symmetry

Ha, Giap ; Zehn, Manfred ; Marinković, Dragan ; Fragassa, Cristiano (2019-03-15)

The behavior of nap-core sandwiches was investigated with a special focus on the effect of symmetry in nap cores. A nap-core is, in general terms, a 3D-formed hollow structure made of knitted textile impregnated by a thermosetting resin. The molding process determines if the nap-core is double-sided (symmetric) or single-sided. The sandwich with nap-core owns various remarkable properties of a ...

Is Tribology Approaching Its Golden Age? Grand Challenges in Engineering Education and Tribological Research

Popov, Valentin L. (2018-11-19)

In spite of its obvious importance, the subject of tribology has relatively low visibility in the engineering community and among the general public. The author's hypothesis is that this problem is at least partly due to the poor “availability” of tribology. In other words, there are practically no simple methods or concepts having high predictive power for tribological problem-solving. That si...

An Accurate Finite Element Method for the Numerical Solution of Isothermal and Incompressible Flow of Viscous Fluid

Abali, Bilen Emek (2019-01-08)

Despite its numerical challenges, finite element method is used to compute viscous fluid flow. A consensus on the cause of numerical problems has been reached; however, general algorithms—allowing a robust and accurate simulation for any process—are still missing. Either a very high computational cost is necessary for a direct numerical solution (DNS) or some limiting procedure is used by addin...

Investigation on Dynamic Response of Rubber in Frictional Contact

Nakano, Ken ; Kawaguchi, Kai ; Takeshima, Kazuho ; Shiraishi, Yu ; Forsbach, Fabian ; Benad, Justus ; Popov, Mikhail ; Popov, Valentin L. (2019-03-26)

In the present work, we analyze a device for measuring the dynamic response of rubber in sliding contact. The principle of the device is to measure excited oscillations of a mechanical system with a sliding contact between a rubber roller and a rigid surface. Depending on the contact properties, varying oscillation amplitudes are measured. The goal is to determine dynamic response properties of...

Survey of Finite Element Method-Based Real-Time Simulations

Marinković, Dragan ; Zehn, Manfred (2019-07-10)

The finite element method (FEM) has deservedly gained the reputation of the most powerful, highly efficient, and versatile numerical method in the field of structural analysis. Though typical application of FE programs implies the so-called “off-line” computations, the rapid pace of hardware development over the past couple of decades was the major impetus for numerous researchers to consider t...

Enhanced Core-Mantle Coupling Due to Stratification at the Top of the Core

Glane, Sebastian ; Buffett, Bruce (2018-10-30)

Fluctuations in the length of day (LOD) over periods of several decades are commonly attributed to exchanges of angular momentum between the mantle and the core. However, the forces that enable this exchange are less certain. Suggestions include the influence of pressure on boundary topography, electromagnetic forces associated with conducting material in the boundary region and gravitational f...

Editorial: Friction and Wear: From Elementary Mechanisms to Macroscopic Behavior

Pohrt, Roman ; Popov, Valentin L. (2019-08-02)

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Artificial Neural Networks (ANNs) as a Novel Modeling Technique in Tribology

Argatov, Ivan (2019-05-29)

In the present paper, artificial neural networks (ANNs) are considered from a mathematical modeling point of view. A short introduction to feedforward neural networks is outlined, including multilayer perceptrons (MLPs) and radial basis function (RBF) networks. Examples of their applications in tribological studies are given, and important features of the data-driven modeling paradigm are discu...

Effect of elastic grading on fretting wear

Willert, Emanuel ; Dmitriev, Andrey I. ; Psakhie, Sergey G. ; Popov, Valentin L. (2019-05-24)

We consider fretting wear in elastic frictional contact under influence of oscillations of small amplitude and investigate the question, how wear damage can be influenced by the introduction of material gradients. To achieve a general understanding we restrict our consideration to media with a power-law dependency of the elastic modulus on depth. In this case, a complete analytical solution can...

Numerical study of the hydraulic excavator overturning stability during performing lifting operations

Mitrev, Rosen ; Marinković, Dragan (2019-05-02)

This article presents a numerical study of the stability of a hydraulic excavator during performing lifting operations. A planar dynamic model is developed with six degrees of freedom, which considers the base body elastic connection with the terrain, the front digging manipulator links, and the presence of the freely suspended payload. Differential equations describing the excavator dynamic be...

Handbook of contact mechanics

Popov, Valentin L. ; Heß, Markus ; Willert, Emanuel (2019-04)

This open access book contains a structured collection of complete solutions of all significant axially symmetric contact problems. It provides solutions for classical profiles such as the sphere, cone or flat cylindrical punch as well as a multitude of other technically relevant shapes, e.g. the truncated cone, the worn sphere, rough profiles, hollow cylinders, etc. Normal, tangential and tors...

Numerical simulation and parametric investigation of the mechanical properties of fabric nap core sandwich

Ha, Giap Xuan (2019)

This research deals with the finite element (FE) simulation and the validation of FE models for a new type of sandwich-structured composite, the so-called nap-core sandwich. The nap-core is made of a two-dimensional knitted fabric impregnated with a thermosetting resin, which underwent deep drawing and curing processes to adopt a permanent three-dimensional shape. The nap-core can be considered...

Adhesive Strength of Contacts of Rough Spheres

Li, Qiang ; Pohrt, Roman ; Popov, Valentin L. (2019-03-26)

The adhesive contact between a parabolic indenter with superimposed roughness and an elastic half space is studied in the JKR-limit (infinitely small range of action of adhesive forces) using the boundary element method with mesh-dependent detachment criterion suggested in 2015. Three types of superimposed roughness are considered: one- and two-dimensional waviness and randomly rough roughness....

Drug Delivery From Polymer-Based Nanopharmaceuticals—An Experimental Study Complemented by Simulations of Selected Diffusion Processes

Macha, Innocent J. ; Ben-Nissan, Besim ; Vilchevskaya, Elena N. ; Morozova, Anna S. ; Abali, Bilen Emek ; Müller, Wolfgang H. ; Rickert, Wilhelm (2019-03-08)

The success of medical therapy depends on the correct amount and the appropriate delivery of the required drugs for treatment. By using biodegradable polymers a drug delivery over a time span of weeks or even months is made possible. This opens up a variety of strategies for better medication. The drug is embedded in a biodegradable polymer (the “carrier”) and injected in a particular position ...

Effect of vibrations on friction in the context of brake squeal

Nguyen, Thai Minh Tuan (2019)

Brake squeal is a case of friction-induced vibration that has not been fully understood yet due to difficulties in both experimental and theoretical approaches. Both approaches are considered in this research in order to contribute knowledge to this topic. Following the idea of the already existing Dynamic Compression Test Rig (DCTR), which shows that the dynamic stiffness of a pad specimen de...

Feuerwiderstand von unversteiften und versteiften CFK Schalenstrukturen und der Einfluss von integrierten Flammschutzlagen

Timme, Sebastian (2019)

Carbon fiber reinforced polymers (CFRP) are progressively used as lightweight materials in primary, load bearing structures for aircraft, ships and trains. However, their mechanical performance under direct flame impingement is identified to be a limiting factor decreasing their weight-saving potential. The fibers often behave inert with respect to pyrolysis while the mechanical properties of t...

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...