国内某核电站用橡胶膨胀节在使用年限内发生贯穿性开裂，采用宏观分析、显微分析、化学成分分析和力学性能测试等手段对其开裂原因进行了分析。结果表明: 膨胀节外层橡胶厚度不均匀、纤维与橡胶存在脱层等制造缺陷是导致该橡胶膨胀节发生开裂的主要原因; 同时，在交变应力和环境介质的双重作用下，橡胶发生老化，加速了橡胶膨胀节的开裂。

The rubber expansion joint which was equipped in a nuclear power plant, cracked in the term of service. The macroscopic and microcosmic cracking character, rubber type and mechanical properties were analyzed by means of morphology examination, composition analysis and mechanical performance test. The results show that the delamination of fiber and rubber and the ununiformity in thickness of the outer layer, which belong to the processing defect, were the main reasons of the cracking. The alternating stress and environment caused aging, which accelerated the cracking of the rubber expansion joint.