한국기계기술학회지 제19권 제4호 (p.499-506)

등이축 굽힘강도를 이용한 중고 자동차용 앞창유리의 안전성 평가

Safety Estimation of Used Vehicle Windshields using Equibiaxial Flexural Strength
키워드 :
Euibiaxial flexural strength,등이축 굽힘강도,Six sigma quality level,식스 시그 마품질 수준,Structural safety factor,구조적 안전율,Two-parameter Weibull distribution,이모수 와이블 분포,Used vehicle windshields,중고 자동차 앞창유리

초록

Recycling is required for all disused vehicle since 2015. The resource recycling act also recommends that most disused vehicle parts have to be reused except for steering and brake parts. Since vehicle windshields should provide protection for drivers and passengers, they need high structural strength and reliability. However, the vehicle windshields themselves contain many defects arising from glass production process. Because the vehicle windshields are exposed to harsh road conditions, they are expected to experience the formation and growth of surface cracks, which can result in sudden failure. In this study, equibiaxial flexural strength tests are performed on used vehicle windshields to examine whether or not the parts can endure high impact stress due to foreign flying objects. The following conclusions can be drawn: (1) The equibiaxial flexural strength of used vehicle windshields fits the two-parameter Weibull distribution. The equibiaxial flexural strength with a 99.9% failure probability is 69MPa for used vehicle windshields. (2) The equibiaxial flexural strength with six sigma quality level and maximum principal stress at vehicle windshield under high impact load are 8.05MPa and 23MPa respectively. Therefore, Structural safety factor of used vehicle windshields is 0.35 and so we should prohibit used vehicle windshields from keeping in reuse.