Hyperelastic-material characterization: A comparison of material constants

Data fitting is an essential part of obtaining material constants for hyperelastic models. However, due to inadequate experimental data, a single-data set, i.e. uniaxial data, is often used for fitting. Despite a frequent use of this method, it is proven that it provides an inaccurate forecast for a characterization. Therefore, as an alternative method, combined-data fitting is usually recommended. In this research, material constants calculated through two different data-fitting methods were evaluated in terms of dispersion. First, material constants were obtained by taking the average of two single-data-set fitted constants (the uniaxial and biaxial data). The second method used the combined-data fitting to find the material constants. Using the constants found, biaxial and uniaxial curves were drawn for each case. For this purpose, three models, the Mooney, Ogden and Yeoh model, were selected. When considering the Mooney model, the averaged method seems not to show a sufficient improvement to the biaxial curve. The Yeoh model reacts equally to both methods, while the Ogden model seems not to be applicable to the averaged method. © 2020 Institute of Metals Technology.