Rubber FEA & Hyperelastic Characterization of Elastomers and Rubber Materials
Hyperelastic Material Modeling using Ansys, Abaqus, Marc in Finite element analysis (FEA) software packages is widely used in the design and analysis of polymeric rubber and elastomer components in the automotive and aerospace industry. Test data from the major principal deformation modes are used to develop the hyperelastic material constants to account for the different states of strain.
Uniaxial tension is the mother of all mechanical tests and provides a very important data point regarding the strength, toughness and quality of the material. ASTM and ISO standards provide the guidance to carry out the tests. The samples are designed so as the specimen length is larger than the width and thickness. This provides a uniform tensile strain state in the specimen.
2) Planar Shear Testing
Planar shear specimens are designed so that the width is much larger than the thickness and the height. Assuming that the material is fully incompressible the pure shear state exists in the specimen at a 45 degree angle to the stretch direction.
3) Volumetric Compression Testing
The measure of compressibility of the material is testing using the Volumetric compression test. A button specimen is used and a hydrostatic state of compression is applied on the specimen to evaluate it.
4) Uniaxial Compression Testing
Uniaxial compression refers to the compression of a button specimen of approx. 29mm diameter and 12.5 mm height. This test can be effectively utilized to replace the expensive biaxial extension test through proper control of the specimen and testing fixture surface friction and proper testing technique and methodology.
5) EquiBiaxial Tension Testing
Biaxial tensile testing is a highly accurate testing technique for mechanical characterization of soft materials. Typical materials tested in biaxial tension are soft and hard rubbers elastomers, polymeric thin films, and biological soft tissues.
The outputs from these tests are the stress vs strain curves in the principal deformation modes. Curve fitting is carried out on the experimental stress vs strain curves to generate the material constants.
These constants are obtained by comparing the stress- strain results obtained from the material model to the stress-strain data from experimental tests. Iterative procedure using least-squares fit method is used to obtain the constants, which reduces the relative error between the predicted and experimental values. The linear least squares fit method is used for material models that are linear in their coefficients e.g Neo-Hookean, Mooney-Rivlin, Yeoh etc. For material models that are nonlinear in the co-efficient relations e.g. Ogden etc, a nonlinear least squares method is used.
Are you looking for a plastic material testing laboratory near me, then look no further. We are a NABL ISO-17025 approved Plastics and Rubber Testing Laboratory based in Ahmedabad, India We provide the following testing services;
AdvanSES’ Plastic Testing Laboratory provides physical and mechanical testing of thermoplastics, polymers and composite materials to ensure these polymer materials meet quality control and application performance requirements
Physical and mechanical testing of polymers ensures that material complies with industry specifications and application requirements of aerospace, automotive, consumer goods, and biomedical industries. As a one-stop plastic testing laboratory for design development, quality control, performance assessment and failure analysis our vast physical and mechanical testing capabilities aincludes ASTM, ISO, IS, BS or DIN standards. Our ISO/IEC 17025:2017 accredited plastic testing laboratory services support design and development projects, Finite Element Analysis FEA, quality control, and problem-solving for all kinds of polymer materials and products.
Ash Content Test: This test is used in determining the amount of fillers in a specimen after the polymer has been burned off and is suitable for the determination of the ash content in rubber compounds. The test methods may be used for quality control. Test Method: ASTM D2584, D5630, ISO 3451
Compression Stress Relaxation Under Constant Deflection: This test is carried out under constant deflection in compression and helps in determining the ability of the material to maintain backforce under compressive stress. This test is used to determine the quality of material and their performance under constant compression application conditions. Test Method: ASTM D6147 B, ISO 3384
Compression Properties Test: This test helps in determining the behaviour of a material when it is subjected to a progressively increasing compressive load. The compressive strength of a material is the force per unit area that it can handle under compression deformation mode. AdvanSES has 3 load frames in its rubber testing laboratory to carry out these tests. Test Method: ASTM D695, ISO 604
Charpy Impact Test: This test helps in determining a thermoplastic or composite material’s resistance to resist impact. This test provides comparative values for various plastics easily and quickly. Test Method: ISO 179
Density And Specific Gravity Test: Our rubber testing laboratory carries out density and specific gravity tests on rubbers, TPEs, thermoplastics etc. This test helps in determining the mass per unit volume of material and the ratio of the mass of a given volume of material. Test Method: ASTM D792, ISO 1183
Flexural Properties Test: This test helps in determining the force required to bend a beam under 3 or 4 points load conditions. The flexural strength of a material is defined as its ability to resist deformation under such 3 point or 4 point loads. Test Method: ASTM D790, ISO 178
3 Point or 4 Point Bend Tests
FTIR (Fourier Transform Infrared Spectrometry) Test: This test helps in identification of polymers, thermoplastics, rubber materials. FTIR (Fourier Transform Infrared Spectroscopy) is an analytical tool for screening and identifying polymer samples. Test Method: ASTM E1252
Izod Impact Test: This test method similar to Charpy’s test method helps in determining a material’s resistance to an impact. The impactor is a swining pendulum. The result of the Izod test is reported in energy absobed per unit of specimen thickness. Test Method: ASTM D256, ISO 180
Tensile Test Of ThermoPlastics: This test helps in measuring the force required to break a specimen and the extent to which the specimen stretches or elongates to that breaking point. The ability of a material to resist breaking under tensile stress is one of the most important and widely used properties of materials used in structural applications. Test Method: ASTM D638, ISO 527
Axial Fatigue Testing of Polymer Thermplastic Materials
Axial Fatigue Test Of ThermoPlastics and Composites: This test helps in understanding the fatigue life of the material or part and assists in generating an S-N curve for the material. The ability of a material to resist breaking under constant cyclic tensile stress is one of the most important and widely used properties of materials used in structural applications. The data from these tests is used in understanding the endurance strength and crack initiation limits of the material. AdvanSES’ plastic testing laboratory can carry out these fatigue tests under stress or strain control and also at room and elevated temperatures. Test Method: ASTM D7791, ISO 13003
The heat deflection temperature of a reinforced or unreinforced polymer material is a measure of polymer’s resistance to distortion under an applied load at elevated temperatures.
Vicat softening temperature tests are used to identify the temperature at which a needle of specified dimensions penetrates into a plastic material specimen for a specified distance under applied loading conditions.
Compared with the Heat Deflection Temperature (HDT) Vicat softening temperature test measures the temperature at which the specimen loses its stiffness and softens. HDT test measures the temperature at which the specimen loses its load bearing capability. The Vicat point is closer to the actual melting or softening point of the polymer.
Test Methods: ASTM D648 and ISO 75; ASTM D1525 and ISO 306
The Directorate General of Civil Aviation (DGCA) in India has set specific requirements for the testing of composite materials used in the aviation industry. DGCA Requirements for Composite material testing in Drone UAV Applications have gone through multiple iterations and new requirements in the past year. These requirements are aimed at ensuring the safety and reliability of aircraft components made from composite materials. Here are some key aspects of the DGCA’s composite material testing requirements:
The test types and methods are;
Full Tensile Properties Testing
Compression Properties Testing
Aging Conditions Testing Under Varilable Tenmperature and Humdity Conditions
Flexure Tests
Impact Tests
DGCA Requirements for Composite material testing in Drone UAV Applications encompasses multiple disciplines. The testing requirements for composite materials used in drone applications may differ slightly from those used in manned aircraft, as the safety considerations and regulatory framework can vary. However, many of the fundamental testing principles remain similar.
It’s important to note that the specific testing requirements may vary depending on the type of drone, its intended use (commercial, military, recreational), and the applicable regulations or standards set by governing bodies or industry organizations. Additionally, composite material suppliers and drone manufacturers may have their own internal testing protocols and acceptance criteria based on their design requirements and risk assessments.
Certification and approval: Composite materials and components intended for use in aircraft must undergo a rigorous certification and approval process by the DGCA. This process involves the review of design data, test reports, and manufacturing procedures to ensure compliance with applicable airworthiness standards.
It’s important to note that the specific testing requirements may vary depending on the application and criticality of the composite component, as well as the type of composite material being used. Manufacturers and suppliers of composite materials and components for the aviation industry in India must comply with the DGCA’s regulations and guidelines to obtain the necessary approvals for their products.
