การวิเคราะห์หาค่าพารามิเตอร์วัสดุของฉนวนกันความร้อนชนิดโพลีเอทิลีนโฟมด้วยวิธีการปรับเส้นโค้ง

Abstract

The purpose of this research is to estimate the constitutive parameters of polyethylene foam which is hyperelastic material. The mechanical response obtained by uniaxial compressive testing, ASTM D3574 type C, Standard specification for testing. Three specimens are cylinder shape with 65 millimeters of diameter and are 25 millimeters in length. The relation between compressive force and stretch is investigated. Then the test data is calculated to the relation in stress and strain. The determination of constitutive parameters is identified by the curve fitting method with 8 hyperelastic models. first, the curve fitting method is chosen in the case of a small strain (0 –10 percent of strain) to compare model efficiency to predict the mechanical response, then determine the maximum percent strain which hyperelastic models can describe the mechanical response. Finally, calculation shear modulus and Young’s modulus from constitutive parameter which obtained form curve fitting. The comparison is agreeable between test data and hyperelastic model. As a result, the hyperelastic model can efficiently clarify the mechanical response under the uniaxial compressive case.