Hyperelastic constants from a modified hardness test using energy balance obtained from FE-analysis

Summary, in English

Manufacturing test specimens, testing them in the laboratory and evaluat-

ing material parameters for finite element analysis is costly and time consum-

ing. In order to simplify the hyperelastic characterisation of rubber materials

an extension of the standard hardness test is here proposed. A number of

indentation depths are chosen for the hardness test and the indentation forces

for these depths are recorded. It is suggested that by this modification, hyper-

elastic constants can be derived from the test. More information can thereby

be provided from the test by a small extra effort. The method is based on

an equivalence of the work done by the external force of the indentor and

the strain energy stored in the rubber material. Displacement control and

the incompressible nature of rubber reduces the problem of determining the

hyperelastic constants to finding a solution to a system of equations with

these constants as unknowns. The method is theoretically evaluated here us-

ing finite element analysis and hyperelastic constants from three real rubber

materials with hardness from 40 to 78 IRHD. The evaluation indicates that

the method can produce hyperelastic constants with good accuracy using this

simple method.

• Author: Per Erik Austrell; Aylin Ahadi
• Department/s: Departments at LTH; Mechanics
• Publishing year: 2012
• Language: English
• Publication/Series: Plastics, Rubber and Composites: Macromolecular Engineering
• Document type: Journal article
• Topic: Applied Mechanics; Building Technologies
• Status: Submitted