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Publications (49)
Hyperelastic material modeling plays a fundamental role in understanding and describing the mechanical behavior of rubber-like materials and other biological tissues. Various mathematical models are employed to model these materials, enabling the precise description of the stress-strain relationship. This paper aims to present a novel methodology t...
The unstable behavior of the isotropic, compressible Mooney-Rivlin hyperelastic model is investigated and described. The constitutive equation is parameterized with the help of the ground-state Poisson’s ratio and the dimensionless ratio of the material parameters [Formula: see text] and [Formula: see text]. Transverse stretch solutions are obtaine...
Motion tracking is a widely used image processing technique, where the goal is to follow and register the movement of specified objects over time, from video recordings. Thanks to the development of optical devices and tracking algorithms, the popularity of the method among researchers is continuously growing in a rich area of applications. Despite...
The most widely-used representation of the compressible, isotropic, neo-Hookean hyperelastic model is considered in this paper. The version under investigation is that which is implemented in the commercial finite element software ABAQUS, ANSYS and COMSOL. Transverse stretch solutions are obtained for the following homogeneous deformations: uniaxia...
This paper is concerned with the material modelling of rubber balls applied for impulse excitation of high-speed rotating milling tools, which is essential for understanding the dynamics of various machining processes. For this purpose, a novel ball-shooter device was developed. The accurate finite element (FE) prediction of the ball impacts requir...
Mussels use byssal threads to secure themselves to rocks and as shock absorbers during cyclic loading from wave motion. Byssal threads combine high strength and toughness with extensibility of nearly 200%. Researchers attribute tensile properties of byssal threads to their elaborate multi-domain collagenous protein cores. Because the elastic proper...
In this paper, a novel approach is used to represent the viscoelastic behavior of cross-linked polyethylene foams at high strain rate: a compressible hyperelastic material model is combined with the Rayleigh damping method. We developed finite element models to simulate the impact tests described in the international assessment protocol of wrestlin...
Description of the impact characteristics of different types of balls has a great importance in sport science and in engineering. The primary objective of the present paper is to investigate the effect of the temperature on the impacts of different types of squash balls from a given company. The shots were performed using a self-built air-cannon. T...
We carry out computational simulations of the Valsalva compression of an inferior vena cava (IVC) with a filter implanted in it. We find that when we treat the IVC wall as simply a boundary between 2 fluids and apply an external pressure on the IVC, the deformation magnitudes and patterns do not agree with data in the literature. We conclude that I...
An efficient numerical integration scheme is proposed for the uniaxial loading of the two-layer viscoplastic (TLVP) model, which is a built-in material model in the commercial finite element software Abaqus. The particular version of the TLVP model under investigation is governed by linear isotropic plastic hardening rule with time-hardening nonlin...
Rubber components usually exhibit changes in their mechanical properties that accumulate over their service life and often determine the need for replacement. This article deals with chemical ageing coupled with mechanical loading. During chemical ageing, changes in the chemical structure of the material lead to alterations in its stiffness and gra...
Polymer adhesive films sandwiched between two rigid solids are a common bonding strategy. The mechanics and consequently the adhesion of such geometrically confined films depend mainly on their thickness, Young's modulus, and the Poisson's ratio of the material. In this work, we explore the effect of a micropatterned subsurface embedded into the ad...
The bending of a superelastic Nitinol cantilever is analyzed, where the deformation is caused by a non-parallel, rigid, friction free constraining surface that approaches the cantilever at an angle, making contact first with its tip. The analysis accounts for geometric nonlinearity and the materially nonlinear behavior of the Nitinol. The constrain...
Polymer adhesive films sandwiched between two rigid solids are a common bonding strategy. The mechanics and consequently the adhesion of such geometrically confined films depend mainly on their thickness, Young's modulus, and the Poisson's ratio of the material. In this work, we explore the effect of a micropatterned subsurface embedded into the ad...
Data to the paper published in Journal of Applied Mechanics: DOI: 10.1115/1.4049182
During the milling of thin-walled workpieces, the natural frequencies might change radically due to the material removal. To avoid resonant spindle speeds and chatter vibration, a precise knowledge of the instantaneous modal parameters is necessary. Many different numerical methods exist to predict the changes; however, small unmodelled effects can...
This work presents explicit dynamic finite element simulations of various impacts of elastic-plastic solid spheres with flat walls. Different analytical models describing the mechanics of the impact phenomenon are also presented. Elastic and elastic-plastic material models for the sphere and the wall are considered during the analyses. The applicab...
This paper is concerned with a punch-test based experimental validation method and the investigation of thickness variation in forming process of a thermoplastic material. One of the key factors that characterize the final geometry of thermoformed parts is thickness variation. The material characterization process is usually based on uniaxial measu...
This paper is concerned with the experimental testing and the constitutive modelling of a thermoplastic microcellular polyethylene-terephthalate (MC-PET) foam on the temperature range of 21–210 °C in order to investigate the temperature-dependent performance of the applied parallel viscoelastic-viscoplastic material model. By means of carefully des...
In this paper, the influence of the chip thicknesses on the contact length between the rake face of the tool and the chip is investigated during orthogonal cutting. This is an important parameter in metal cutting, since it determines the cutting force over the rake face and the heat transfer between the tool and the workpiece. Therefore, it plays s...
Following contribution deals with characterization of cork-rubber composite behaviour. Based on results of performed tension, compression and shear experiments were calibrated parameters of advanced material models in Mcalibration software [1]. There were chosen material models available in Abaqus software [2]. The best conformity was found for Ber...
This work presents dynamic finite element simulations of various pellet impacts in order to investigate their applicability during impulse excitation in modal analysis. Compared to the classical impulse excitation with modal hammer, the approach of pellet shots provides shorter impact time and reduces the multi-hitting effect leading a wider releva...
The adhesion of a punch to a linear elastic, confined layer is investigated. Numerical analysis is performed to determine the equivalent elastic modulus in terms of layer confinement. The size of the layer relative to the punch radius and its Poisson’s ratio are found to affect the layer stiffness. The results reveal that the equivalent modulus of...
This contribution presents the material characterization of an airsoft pellet, which is applied for the excitation of machine tools in order to reduce the multi-hitting effect during the impact. The material behavior of the pellet shows nonlinear elastic, plastic and viscous properties. Consequently, to obtain the exciting force during the impact a...
This paper is concerned with the theory of incompressible visco-hyperelastic solids. Closed-form stress solutions are derived for five different visco-hyperelastic material models in uniaxial extension. Two loading scenarios are considered: uniaxial extension with constant true strain-rate; uniaxial extension with constant engineering strain-rate....
This article deals with the visco-hyperelastic modelling approach for compressible polymer foam materials. Polymer foams can exhibit large elastic strains and displacements in case of volumetric compression. In addition, they often show significant rate-dependent properties. This material behaviour can be accurately modelled using the visco-hyperel...
Despite crucial efforts invested into computational methods, explicit dynamics simulation of cutting operations may still be unacceptably expensive. Therefore, in many cases a two-dimensional model is considered. Here an overview of the possibilities of two-dimensional simulations is given. For this, simulation and measurement of a straight turning...
This article presents the visco-hyperelastic material modelling approach for open-cell polymer foams. The visco-hyperelastic material models combine the long-term hyperelastic and viscoelastic material models using finite-strain formulation. The long-term behavior is modelled using the Ogden-Hill's compressible hyperelastic model termed as “hyperfo...
The most widely used approach to model the large strain elastic response of polymer foams in a finite element (FE) simulation is the use of the Ogden–Hill compressible hyperelastic material model. This model is implemented and termed as “hyperfoam” material model in the commercial FE software ABAQUS. The hyperfoam model is able to characterize the...
A memóriahabok deformációja nagy alakváltozás mellett időfüggő tulajdonságokat is mutat, emiatt speciális viszko-hiperelasztikus anyagmodelleket kell alkalmaznunk a modellezésük során. Az anyagmodellt a megfelelő időfüggetlen hiperelasztikus és a relaxációt leíró viszkoelasztikus anyagmodell ötvözésével állíthatjuk elő. A konstitutív egyenletből el...
This article presents an experimental investigation of the effect of the skin layer on the mechanical behavior of a closed-cell polymeric foam material. The skin layer is a thin layer with increased density due to the manufacturing processes, which results in inhomogeneity. The skin-layer effect is investigated by comparing the stretch-stress chara...
This article presents a new biaxial compresssion test fixture designed for polymeric foam materials. The main advantage of the new fixture is that it is designed for uniaxial testing machines, therefore the biaxial compression measurement does not require a multiaxial test system. The geometries of the fixture and the test specimen, respectively, e...
This paper presents the exact stress solution of the non-associative Drucker–Prager elastoplastic model governed by linear isotropic hardening rule. The stress integration is performed under constant strain-rate assumption and the derived formulas are valid in the setting of small strain elastoplasticity theory. Based on the time-continuous stress...
This article presents the analytical strain solution of the rateform non-associative elastic-plastic constitutive model using the Drucker-Prager yield criterion with linear isotropic hardening. The strain solution is obtained using constant stress rate assumption. The solution for the deviatoric radial loading case is also presented. In addition, t...
Recently, the authors proposed a new integration scheme for the von Mises elastoplasticity model with combined linear isotropic-kinematic hardening. In this paper, the numerical accuracy and the computational efficiency of this method are examined in detail. In addition, the key issues of its numerical implementation are also discussed. The main ad...
Elastoplastic constitutive models play a crucial task in engineering problems. The classical models are widely accepted and applied for various cases of elastoplastic calculations. The commercial finite element softwares include these models in general, from which, the Prandtl-Reuss constitutive relation is the most widely used one. This article is...
The main purpose of this work is to present two semi-analytical solutions for the von Mises elastoplasticity model governed by combined linear isotropic-kinematic hardening. The first solution (SOLε) corresponds to strain-driven problems with constant strain rate assumption, whereas the second one (SOLσ) is proposed for stress-driven problems using...
This work demonstrates the performance of a new stress integration procedure based on an exact solution of the von Mises elastoplasticity model governed by combined linear hardening. The new method has been implemented into the finite element code ABAQUS via the UMAT subroutine. The efficiency of the new method is compared to the ABAQUS internal st...
This paper presents a summary of the new semi-analytical integration method presented in (10) for von Mises elastoplas- ticity model with combined linear isotropic-kinematic hardening within a small deformation range. Solutions for the case of con- stant strain rate and constant stress rate assumptions are also presented. Furthemore, it is shown ho...
