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Home>Technical Downloads>Technical Papers

Technical Papers:

1. Testing Elastomers for Hyperelastic Material Models in Finite Element Analysis
The paper provides pictures of the various experiments and discusses the relationship between experimental loadings and hyperelastic material models. (PDF: 2.7 MB / 8 pages)


2. Experimental Loading Conditions Used to Implement Hyperelastic and Plastic Material Models
Loading variables such as strain rate, strain direction, maximum strain, relaxation, cyclic behavior and plasticity are outlined to provide a context for the design of experiments needed to define hyperelastic and plastic material models based on the needs of the application. (PDF: 930 KB / 14 pages).


3. Equibiaxial Stretching of Elastomeric Sheets, An Analytical Verification of Experimental Technique
By Jim Day, GM Powertrain and Kurt Miller, Axel Products, Inc. This paper provides an analysis and verification of the radial biaxial test used at Axel Products, Inc. Appendix A of this document provides an analysis of the compression button experiment and details the adverse effects of friction. (PDF: 751 KB / 8 pages)


4. Measuring the Dynamic Properties of Elastomers for Analysis:This paper provides an outline for the dynamic testing of elastomers for the characterization of dynamic properties needed to define analytical models where small dynamic strains are present on large nonlinear mean strains. This includes acoustic characterization. (PDF: 2.8 MB / 7 pages)


5. Using Slow Cyclic Loadings to Create Stress Strain Curves for Input into Hyperelastic Curve Fitting Routines
This is an Axel Products, Inc. support document which reviews the effects of loading, unloading and strain levels on elastomers. The limitations of hyperelastic material models as they relate to laboratory material data is reviewed. (PDF: 565 KB / 4 pages)


6. Application of Energy Based Fatigue Crack Growth to Elastomer Compound Development
By Don Young, Independent Consultant. Brief theory and background are provided to show the importance and relevance of using a fracture mechanics approach to model and evaluate rubber materials. The experimental approach is briefly discussed, and alternate forms of analysis are described to properly model strain, stress and energy controlled deformations. (PDF: 1107 KB / 14 pages)


7. Stress Relaxation Tests, Technical Report 98/1, by Mr.Göran Spetz of Elastocon AB, SWEDEN
This is a discussion of long term stress relaxation testing and the use of Arrhenius plots to estimate the useful lifetime of elastomeric components. (PDF: 127 KB / 4 pages)


8. Thermal conductivity, thermal diffusivity, and specific heat of thin samples from transient measurements with hot disk sensors, by Mattias Gustafsson, Ernest Karawacki and Silas E Gustafsson. (PDF: 7,280 KB / 4 pages)


9. When F does not Equal Ku, White Paper, by MSC Software
This easy to read paper explains how to spot a nonlinear problem and discusss the nature of nonlinearities in analysis. (PDF: 3120 KB / 16 pages)


10. Nonlinear Finite Element Analysis of Elastomers, White Paper, by MSC Software
This paper provides a broad tutorial on this topic covering analytical issues, material behavior, case studies and the required laboratory experiments (PDF: 2816 KB / 66 pages)


11. Characterization of Polymers by TMA, Perkin-Elmer application paper by W.J. Sichina
This is a broad based discussion on the use of thermal mechanical analysis (TMA) to investigate the properties of polymers. (PDF: 264 KB / 5 pages)


12. Examination of finite element analysis and experimental results of quasi-statically loaded acetal copolymer gears, by Paul Wyluda, Ticona and Dan Wolf, MSC Software.
An elastic-plastic finite element analysis of the quasi-static loading of two acetal copolymer gears in contact is preformed. Load verses rotation of the gear set is compared to actual experimental results. (PDF: 389 KB / 7 pages)


13. Implications of the Mullins Effect on the Stiffness of a Pre-loaded Rubber Component, by Ryan E. Paige, Will V. Mars, Cooper Tire & Rubber Company, ABAQUS User's Conference, Cambridge, Massachusetts, May 2004.
Many engineered rubber components are pre-loaded during manufacture or installation in such a way that the rubber experiences compressive loads that are partially relieved during operation.  In this paper, we investigate the consequences of applying this type of loading when the rubber exhibits a Mullins effect.  The Mullins effect is a dependence of the hyperelastic response on the maximum deformation previously experienced.  ABAQUS contains a new model for this effect, and we first examine the significance of the model parameters.  Then we show that the total stiffness of a rubber component may either decrease or increase significantly by including the Mullins effect. (PDF: 373 KB / 15 pages)


14. Why it is necessary to use data from more than one strain field in determining the Helmholtz free-energy (strain energy) density function, by Kenneth N. Morman, PhD, The ANSOL Corporation
A graphical presentation with appropriate references explaining the need for experiments in mutiple states of strain to adequately define "hyperelastic" material models. (PDF: 253 KB / 4 pages)


15. Elastomer Rate-dependence: A Testing and Material Modeling Methodology, by Tod Dalrymple and Jaehwan Choi, Dassault Systems Simulia Corp. and Kurt Miller, Axel Products, Inc.

Stress relaxation testing at very early times (fraction of a second) combined with test data from a set of constant strain-rate uniaxial tests is used to create hyperelastic/viscoelastic material models.  A robust method of testing the material and a robust method of material model calibration is developed to capture the strain-rate sensitivity of elastomeric materials. This material representation is intended for simulations of dynamic transient loadcases. The focus is on the use of the hyperelastic and viscoelastic Prony series representation in the Abaqus/Standard and Abaqus/Explicit simulation software. This technique and resulting material model represents the material’s strain-rate dependence during loading quite accurately and thus can be used effectively to simulate peak load conditions during dynamic transient events. Unfortunately, the resulting hyperelastic plus Prony series viscoelastic material model does not represent the material’s hysteresis loop during the load-unload cycle accurately. This paper presents the test methods developed, a sample of material test data, and the resulting material model and material model responses. (PDF: 6.65 MB / 20 pages)


16. Modelling Carpet for use in Occupant Crash Simulations, by Dylan Thomas, Honda R&D Americas
Prediction of occupant injury using crash simulations can require numerical representation of materials that are not normally included within the structural model. Intuitively, it makes sense that the carpet would be required to predict the tibia index during frontal crash events; however, there appears to be little published on the topic. The tibia index is an injury criteria that needs to be predicted during IIHS frontal offset occupant simulations, but is also be looked at during unbelted FMVSS 208 simulations. Since carpet behaves quite differently during compressive and tensile loading, a numerical representation that can stably capture both regimes during occupant modelling is needed.
This paper outlines a method to model the carpet using a specific meshing method and two material models. Shell elements in combination with the *PIECEWISE_LINEAR_PLASTICITY material model are used to model the tensile load carrying capacity of the carpet, while brick elements with the *MAT_FU_CHANG_FOAM material model are used to represent the compressibility of the carpet. Validation of using this modelling method with test data is presented, as well as the application of the carpet model in larger occupant models. (PDF: 0.65 MB / 12 pages)


17. Understanding Frequency Domain Viscoelasticity in Abaqus, By Saurabh Bahuguna, Randy Marlow*, and Tod Dalrymple of Dassault Systèmes Simulia Corp., Great Lakes Region
In this paper, the frequency domain viscoelastic model in Abaqus is explored. The input requirement of the model from uniaxial dynamic tests at several frequencies is detailed. (PDF: 0.13 MB / 13 pages)

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Home>Technical Downloads>Test Briefs

Test Briefs:

21. Compression or Biaxial Extension?
Why is the biaxial extension experiment used for elastomers? Why is the compression test an undesirable test when developing test data for finite element analysis? This short paper addresses these questions. (PDF: 0.7 MB / 3 pages)


22. Thermal Conductivity of Rubber and Plastic Materials
This is a brief description of the operation of the transient plane source measurement technique used at Axel Products to measure the themal conductivity of rubber and plastic materials. (PDF: 1.47 MB / 2 pages)


23. The Effects of Large Temperature Changes on Elastomer Seal Performance
This paper describes the effects of large temperature changes on elastomer seals and an experimental approach to measuring these effects. (PDF: 0.7 MB / 5 pages)


24. Testing Fine Wire
This brief examines some of the difficulties encountered in wire testing and outlines some techniques that may be successful in overcoming these difficulties. (PDF: 0.6 MB / 2 pages)


25. Measuring Rubber and Plastic Friction for Analysis
The frictional forces generated between plastic, rubber and various hard surfaces are often represented with a simple coefficient of friction (COF) value yet in reality can be a function of material, surface finish, temperature, rate of relative movement, time and normal pressure.  Using frictional measurements where these parameters are matched to the application conditions will help to create a more realistic analysis. Issues and experiments are descibed. (PDF: 1.3 MB / 4 pages)


26. Testing at High Strain Rates
Issues and pictures related to high strain testing are presented. Data for high strain rate testing of sheet steel, structural plastic and crushable foams is shown. (PDF: 2347 KB / 3 pages)


27. Long Term Creep and Long Term Stress Relaxation Experiments for Rubber and Plastic Materials
Long term creep and long term stress relaxation experiments provide valuable data but have experimental limitations. The experiments used at Axel Products are described. (PDF: 3.4 MB / 4 pages)

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Home>Technical Downloads>Presentations

Presentations:

51. FEA of Elastomers and Gaskets in ABAQUS, overheads
by Tod Dalrymple, HKS Michigan, presented at the ASTM Finite Element Analysis Focus Event, October 2000, Orlando, Florida. (PDF: 4983 KB / 43 pages)


52. Rubber Material Curve Fitting with ABAQUS/ CAE, overheads
by Tod Dalrymple, HKS Michigan and Kurt Miller, Axel Products, Inc., presented at the 2000 Michigan Regional ABAQUS Users' Meeting on November 16, 2000. (PDF: 3045 KB / 34 pages)


53. Experimental Loading Conditions Used to Implement Hyperelastic and Plastic Material Models, overheads
by Kurt Miller, Axel Products, Inc., presented at the MSC 2nd Worldwide Automotive Conference. (PDF: 2911 KB / 30 pages)


54. Measuring Elastomer Properties at Audible Frequencies, overheads
by Kurt Miller, Axel Products, Inc., presented at the HKS 2000 ABACUS Users' Conference on June 2, 2000. (PDF: 1039 KB / 15 pages)


55. Analysis of Elastomeric Components & Assemblies: Some Practical Considerations, overheads
by Bill C. Brothers and Alan R. Leewood, AC Engineering, West Layfayette, Indiana, USA presented at Elastomer - Fea Forum 1999, 3rd International Symposium on Finite Element Analysis of Rubber and Rubber- like Materials, May 19 th and 20 th , 1999, Akron, Ohio USA. (PDF: 658 KB / 30 pages)


56. Measuring Material Properties to Build Material Models in FEA, overheads
by Kurt Miller, Axel Products, Inc. These are the overheads from a general presentation given by Kurt Miller at various venues. The presentation includes laboratory pictures and test data examples.
Download MatPropsFEA.pdf. (This is a BIG file): (PDF: 7922 KB / 61 pages)


57. Elastomer Analysis Using MARC, overheads
Prepared by: Daniel S. Wolf, MARC Analysis Research Corp.,Palo Alto, CA, USA for: Elastomer - Fea Forum 1999, 3rd International Symposium on Finite Element Analysis of Rubber and Rubber- like Materials, May 19 th and 20 th , 1999, Akron, Ohio USA
These overheads contain several testing pictures and as well as curve fitting examples and actual component examples. (PDF: 1192 KB / 25 pages)


58. Stress Relaxation of Elastomers under Constant Strain, overheads
Axel Products, Inc. and Elastocon AB sponsored seminar on Stress Relaxation in Elastomers on January 27, 1999. (PDF: 530 KB / 18 pages)


58. Compressive Stress Relaxation Anomalies, overheads
by Jim Madsen, Materials Laboratory Manager, Freudenberg-NOK.This presentation provides an overview of long term compressive stress relaxation (CSR) experiments and presents some of the challenges associated with the use of CSR data. (PDF: 600 KB / 36 pages)


59. Factors that Affect the Fatigue Life of Rubber: A Literature Survey, overheads
by W. V. Mars - Cooper Tire & Rubber Co., A. Fatemi - U. of Toledo.Will provides a terrific overview of the factors that effect the fatigue and durability of rubber. (PPT: 1115 KB / 25 pages)


60. Experimental Considerations in the Measurement of Thermal Relaxation and Recovery of Strained Seals, overheads
by Kurt Miller, Axel Products, Inc., presented at the Detroit Rubber Group. (PPT: 4.3 MB)


59. Elastomer Rate-dependence, overheads
by Tod Dalrymple ., Presented at the Fall 172nd Technical Meeting of the Rubber Division of the American Chemical Society, Inc. (PDF: 673 MB / 21 pages)

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