When performing a stress-relaxation test of soft tissues, a small preload is usually applied to the specimen to remove slack, and this preload is generally be neglected.

对软组织进行应力松弛试验时可给样本施加一个小的预加力来去除样本的松弛，该预加力通常被忽略。

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As the piezoelectric stack actuator can withstand pressure only, a preload device is designed to ensure that the intelligent active member can experience tensile stress.

由于压电叠层作动器只能承受压力，为了保证压电智能主动杆能够承受一定的拉力，设计了预压装置。

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