비선형 유한요소법을 사용한 고무 마운트의 정특성 해석에 있어서 체적 탄성 계수의 역할

Abstract

고무 스프링의 정 스프링 상수를 해석하기 위해 비선형 유한요소법을 사용할 때, 고무의 구성 방정식은 초탄성 재료 모델로 표현한다. 일반적으로 엔진 마운트의 설계를 위한 초탄성 모델의 재료 상수들은 일축 압축 시험과 단순 전단 시험 결과만을 이용하여 구해진다. 그러나 체적 시험을 생략하고 고무를 비압축성으로 가정한 비선형 유한 요소 해석 결과는 매우 부정확한 결과를 가져올 수 있다. 본 연구는 수치 해석 결과에 미치는 체적 탄성 계수의 영향을 조사하여, 엔진 마운트의 형상 계수가 클 때는 체적 변형율의 정확한 측정이 다른 두 물성치의 측정과 마찬가지로 중요하다는 것을 보이고 있다.

When a nonlinear finite element analysis is used to find the static spring constants of a rubber spring, the constitutive equations of the rubber are represented by a hyperelastic model, of which material constants are determined from the different types of material tests. Uniaxial compression and simple shear tests are usually chosen due to their experimental conveniences, while volumetric test is often underestimated and omitted. But the hyperelastic model obtained from the two kinds of tests alone can result in rather poor performance for a certain engine mount when the rubber is assumed to be incompressible in teh finite element procedure. This study investigates the influences of bulk modulus, which are found to be as equally important as other two material properties, on the numerical results when the form factor of the mount becomes large.

When a nonlinear finite element analysis is used to find the static spring constants of a rubber spring, the constitutive equations of the rubber are represented by a hyperelastic model, of which material constants are determined from the different types of material tests. Uniaxial compression and simple shear tests are usually chosen due to their experimental conveniences, while volumetric test is often underestimated and omitted. But the hyperelastic model obtained from the two kinds of tests alone can result in rather poor performance for a certain engine mount when the rubber is assumed to be incompressible in teh finite element procedure. This study investigates the influences of bulk modulus, which are found to be as equally important as other two material properties, on the numerical results when the form factor of the mount becomes large.