scholarly journals Inverse Approach to Evaluate the Tubular Material Parameters Using the Bulging Test

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yulong Ge ◽  
Xiaoxing Li ◽  
Lihui Lang
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Material Properties ◽  
Hybrid Algorithm ◽  
Material Parameters ◽  
Inverse Approach ◽  
Material Evaluation ◽  
Levenberg Marquardt ◽  
Bulging Test ◽  
Inverse Procedure

Tubular material parameters are required for both part manufactory process planning and finite element simulations. The bulging test is one of the most credible ways to detect the property parameters for tubular material. The inverse approach provides more effective access to the accurate material evaluation than with direct identifications. In this paper, a newly designed set of bulging test tools is introduced. An inverse procedure is adopted to determine the tubular material properties in Krupkowski-Swift constitutive model of material deformation using a hybrid algorithm that combines the differential evolution and Levenberg-Marquardt algorithms. The constitutive model’s parameters obtained from the conventional and inverse methods are compared, and this comparison shows that the inverse approach is able to offer more information with higher reliability and can simplify the test equipment.

An inverse approach to the characterisation of material parameters of piezoelectric discs with triple-ring-electrodes

2019 ◽  
Vol 86 (2) ◽  
pp. 59-65
Author(s):  
Nadine Feldmann ◽  
Benjamin Jurgelucks ◽  
Leander Claes ◽  
Veronika Schulze ◽  
Bernd Henning ◽  
...  
Keyword(s):  
Material Properties ◽  
Measurement Procedure ◽  
Material Parameters ◽  
Inverse Approach ◽  
Precise Knowledge ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Set Up ◽  
Optimisation Procedure ◽  
Single Set

AbstractFor its usage in simulation-based design processes a precise knowledge of the employed material properties is inevitable. In the case of piezoelectric ceramics, the provided material parameters often suffer from large uncertainties and even inconsistencies since the standardised measurement procedure needs several specimens to determine a single set of material parameters. In contrast, the presented measurement set-up allows to calculate material parameters using one unique disc-shaped specimen with an optimised electrode topology. Using an inverse problem approach, fitting material parameters can be found using an optimisation procedure.

scholarly journals Effects of region and sex on the mechanical properties of the glenohumeral capsule during uniaxial extension

2010 ◽  
Vol 108 (6) ◽  
pp. 1711-1718 ◽  
Author(s):  
Carrie A. Voycheck ◽  
Eric J. Rainis ◽  
Patrick J. McMahon ◽  
Jeffrey A. Weiss ◽  
Richard E. Debski
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Material Properties ◽  
Surgical Repair ◽  
Glenohumeral Joint ◽  
Uniaxial Extension ◽  
Posterior Capsule ◽  
Finite Element Models ◽  
Men And Women ◽  
Glenohumeral Capsule

Surgical repair of the glenohumeral capsule after dislocation ignores regional boundaries of the capsule and is not sex specific. However, each region of the capsule functions to stabilize the joint in different positions, and differences in joint laxity between men and women have been found. The objectives of this research were to determine the effects of region (axillary pouch and posterior capsule) and sex on the material properties of the glenohumeral capsule. Boundary conditions derived from experiments were used to create finite-element models that applied tensile deformations to tissue samples from the capsule. The material coefficients of a hyperelastic constitutive model were determined via inverse finite-element optimization, which minimized the difference between the experimental and finite-element model-predicted load-elongation curve. These coefficients were then used to create stress-stretch curves representing the material properties of the capsule regions for each sex in response to uniaxial extension. For the axillary pouch, the C1(men: 0.28 ± 0.39 MPa and women: 0.23 ± 0.12 MPa) and C2(men: 8.2 ± 4.1 and women: 7.7 ± 3.0) material coefficients differed between men and women by only 0.05 MPa and 0.5, respectively. Similarly, the posterior capsule coefficients differed by 0.15 MPa (male: 0.49 ± 0.26 MPa and female: 0.34 ± 0.20 MPa) and 0.6 (male: 7.8 ± 2.9 and female: 7.2 ± 3.0), respectively. No differences could be detected in the material coefficients between regions or sexes. As a result, surgeons may not need to consider region- and sex-specific surgical repair techniques. Furthermore, finite-element models of the glenohumeral joint may not need region- or sex-specific material coefficients when using this constitutive model.

The Parametric Studies of Brain Materials in the Analysis of Head Impact

2006 ◽  
Author(s):  
Dalong Li ◽  
Mariusz Ziejewski ◽  
Ghodrat Karami
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Material Properties ◽  
Material Behavior ◽  
Material Models ◽  
Material Parameters ◽  
Multiple Materials ◽  
The Brain ◽  
Brain Tissues

Crash analysis and head injury biomechanics are very important fields in biomedical research due to the devastating consequences of traumatic brain injuries (TBI). Complex geometry and constitutive models of multiple materials can be combined with the loading conditions in finite element head model to study the dynamic behavior of brain and the TBI. In such a modeling, the proper regional material properties of brain tissues are important. Brain tissues material properties have not been finally determined by experiments, and large variations in the test data still exist and the data is very much situation-dependent. Therefore, parametric analysis should be performed to study the relationship between the material properties and the brain response. The main purpose of presenting this paper is to identify the influence of material constitutive properties on brain impact response, to search for an improved material model and to arrive at a better correlation between the finite element model and the cadaver tests data. In this paper a 3-D nonlinear finite element method will be used to study the dynamic response of the human head under dynamic loading. The finite element formulation includes detailed model of the skull, brain, cerebral-spinal fluid (CSF), dura mater, pia mater, falx and tentorium membranes. The brain is modeled as linear viscoelastic material, whereas linear elastic material behavior is assumed for all the other tissue components. The proper contact and compatibility conditions between different components have been implemented in the modeling procedure. The results for the direct frontal impacts will be shown for three groups of material parameters. The parametrical analysis of tissue material models allows to examines the accuracy of three different set of material parameters for brain in a comparison with the prediction of the head dynamic response of Nahum's human cadaver direct impact experiment. Three sets of suggested material parameters are examined. It is concluded that although all three groups of material models will follow the dynamic behavior of the head and brain behavior, but the parametric data considered in this paper have a closer resemblance to the experimental behavior.

Finite element implementation of viscoelastic and viscoplastic models

2020 ◽  
Vol 37 (8) ◽  
pp. 2561-2585
Author(s):  
Hossein Sepiani ◽  
Maria Anna Polak ◽  
Alexander Penlidis
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Three Dimensional ◽  
Small Strain ◽  
Test Time ◽  
Nonlinear Behaviour ◽  
Content Type ◽  
Material Parameters ◽  
Viscoplastic Models

Purpose The purpose of this study is to present a finite element (FE) implementation of phenomenological three-dimensional viscoelastic and viscoplastic constitutive models for long term behaviour prediction of polymers. Design/methodology/approach The method is based on the small strain assumption but is extended to large deformation for materials in which the stress-strain relation is nonlinear and the concept of incompressibility is governing. An empirical approach is used for determining material parameters in the constitutive equations, based on measured material properties. The modelling process uses a spring and dash-pot and a power-law approximation function method for viscoelastic and viscoplastic nonlinear behaviour, respectively. The model improvement for long term behaviour prediction is done by modifying the material parameters in such a way that they account for the current test time. The determination of material properties is based on the non-separable type of relations for nonlinear materials in which the material properties change with stress coupled with time. Findings The proposed viscoelastic and viscoplastic models are implemented in a user material algorithm of the FE general-purpose program ABAQUS and the validity of the models is assessed by comparisons with experimental observations from tests on high-density polyethylene samples in one-dimensional tensile loading. Comparisons show that the proposed constitutive model can satisfactorily represent the time-dependent mechanical behaviour of polymers even for long term predictions. Originality/value The study provides a new approach in long term investigation of material behaviour using FE analysis.

scholarly journals Lifetime Assessment and Optimization of a Welded A-Type Frame in a Mining Truck Considering Uncertainties of Material Properties and Structural Geometry and Load

2019 ◽  
Vol 9 (5) ◽  
pp. 918 ◽  
Author(s):  
Chengji Mi ◽  
Wentai Li ◽  
Xuewen Xiao ◽  
Haigen Jian ◽  
Zhengqi Gu ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Material Properties ◽  
Optimal Solution ◽  
Collaborative Optimization ◽  
Fatigue Performance ◽  
Dynamics Simulation ◽  
Nsga Ii ◽  
Element Analysis ◽  
Material Parameters

Abstract: In order to improve the fatigue performance of a welded A-type frame in a heavy off-road mining truck, a novel method was presented to implement lifetime and weight collaborative optimization while considering uncertainties in geometry dimension, material properties, and bearing load. The mechanical and cyclic material parameters were obtained from experimental work to characterize the base metal and the weldment. The finite element model of a welded A-type frame was constructed to analyze stress distribution and predict fatigue life, the force time histories of which were acquired from multi-body dynamics simulation. The simulated failure position and fatigue life had a good agreement with the actual results. Then, both structural lifetime and weight were considered as optimization objectives. The thickness of main steel plates and elastic and cyclic material parameters were chosen as uncertain design variables as well as main loads at connection locations. The fifty sample points in the light of Latin hypercube sampling method and its responses calculated by finite element analysis were supposed to build the approximation model based on the Kriging approximation method. After its fitting precision was guaranteed, the non-dominated sorting genetic algorithm II (NSGA-II) was utilized to find the optimal solution. Finally, the fatigue life of a welded A-type frame was increased to 2.40×105 cycles and its mass was lessened by 8.2%. The optimized results implied that good fatigue performance of this welded A-type frame needs better welding quality, lower running speed for downhill and turning road surface, and thicker front plates.

Numerical Mechanical Analysis of Filled Rubber under Different Deformation States Based on a New Hyperelastic Constitutive Model

2021 ◽  
Vol 1032 ◽  
pp. 15-22
Author(s):  
Xin Tao Fu ◽  
Ze Peng Wang ◽  
Lian Xiang Ma
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Constitutive Model ◽  
Pure Shear ◽  
Mechanical Analysis ◽  
Uniaxial Tensile ◽  
Material Parameters ◽  
Finite Element Software ◽  
Filled Rubber ◽  
Deformation State

The accuracy of the rubber constitutive model characterizing experiment data has a crucial influence on the mechanical analysis of rubber structures. In this paper, a new improved hyperelastic constitutive model is proposed, and the model is derived into the stress-strain forms of uniaxial tension, equibiaxial tension and pure shear. Based on the experimental data of filled rubber, the material parameters of each deformation state are obtained by using the newly proposed rubber hyperelastic constitutive model, and the uniaxial tensile (UT), Equibiaxial tension (ET) and Pure shear (PS) specimens are simulated and calculated in the finite element software. the stress state of each finite element specimen is analyzed and the obtained simulation data are compared with the experimental data. It is found that the new model can accurately characterize the hyperelastic mechanical properties of the experimental specimens in different deformation states. At the same time, the reasons for the deviation from the experimental data in the process of plane tensile simulation are analyzed and explained comprehensively. The reliability and accuracy of the classical rubber constitutive relations of polynomial models and eight-chain model are studied. the results show that different hyperelastic models have different ability to describe the hyperelastic behavior in different deformation states. the hyperelastic constitutive model proposed in this paper can be easily embedded into finite element software and has the advantages of accurate results, few material parameters and simple testing.

Derivation of the Depth Dependent Mechanical Characteristics of Ion-Irradiated F82H Steels by Using a Finite Element Analysis

2013 ◽  
Author(s):  
Jongmin Kim ◽  
Chansun Shin ◽  
Sanghoon Noh ◽  
Bongsang Lee
Keyword(s):  
Finite Element ◽  
Neutron Irradiation ◽  
Material Properties ◽  
Nuclear Power ◽  
Power Plants ◽  
Ion Irradiation ◽  
Strain Curve ◽  
Irradiation Condition ◽  
Irradiation Effect ◽  
Material Parameters

Changes in mechanical material properties caused by neutron irradiation during the nuclear power plant operation are one of the key safety issues for the maintenance and long-term operation of nuclear power plants (NPPs). Ion-irradiation is widely used to simulate neutron irradiation condition in laboratory environment, such an irradiation effect on the material property is varied along the depth of a material subjected to ion irradiation. Since the ion irradiation induces a depth-dependent dose from the surface of a material. The load-depth (L-h) curve and nano-hardness measured from nanoindentation, which is used to obtain the material properties using small specimen, normal to the ion-irradiated surface is a result of complex average of varying mechanical property along the indentation depth. The present paper investigates a method to evaluate depth (or dose)-dependent mechanical properties by combining experiment and finite element (FE) analysis of nanoindentation. The method is applied to reduced activation ferritic-martensitic steel, F82H. The material was ion-irradiated using Fe3+ ions of 1.7 MeV accelerating voltage at 300°C. The applicability of reverse algorithm was reviewed, and separate FE analyses were performed to determine material parameters by using trial set of material parameters. The ion-damaged surface layer was divided into several layers in the FE modeling. The L-h curve using determined stress-strain curve by using trial set of material parameters was found to be better agreement than reverse algorithm with experimentally measured one by nanoindentation. The advantage and limitation of the method investigated in this study will be discussed in detail.

Lifetime Prediction of Tires with Regard to Oxidative Aging5

2008 ◽  
Vol 36 (1) ◽  
pp. 63-79 ◽  
Author(s):  
L. Nasdala ◽  
Y. Wei ◽  
H. Rothert ◽  
M. Kaliske
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Temperature Distribution ◽  
Superposition Principle ◽  
Accelerated Aging ◽  
Material Model ◽  
Aging Behavior ◽  
Element Analysis ◽  
Material Parameters ◽  
Reaction Processes

Abstract It is a challenging task in the design of automobile tires to predict lifetime and performance on the basis of numerical simulations. Several factors have to be taken into account to correctly estimate the aging behavior. This paper focuses on oxygen reaction processes which, apart from mechanical and thermal aspects, effect the tire durability. The material parameters needed to describe the temperature-dependent oxygen diffusion and reaction processes are derived by means of the time–temperature–superposition principle from modulus profiling tests. These experiments are designed to examine the diffusion-limited oxidation (DLO) effect which occurs when accelerated aging tests are performed. For the cord-reinforced rubber composites, homogenization techniques are adopted to obtain effective material parameters (diffusivities and reaction constants). The selection and arrangement of rubber components influence the temperature distribution and the oxygen penetration depth which impact tire durability. The goal of this paper is to establish a finite element analysis based criterion to predict lifetime with respect to oxidative aging. The finite element analysis is carried out in three stages. First the heat generation rate distribution is calculated using a viscoelastic material model. Then the temperature distribution can be determined. In the third step we evaluate the oxygen distribution or rather the oxygen consumption rate, which is a measure for the tire lifetime. Thus, the aging behavior of different kinds of tires can be compared. Numerical examples show how diffusivities, reaction coefficients, and temperature influence the durability of different tire parts. It is found that due to the DLO effect, some interior parts may age slower even if the temperature is increased.

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