猪后腿肌肉的冲击压缩特性实验

Dynamic compression experiments of porcine ham muscle

波形整形技术使试样满足应力均匀条件和恒定应变率加载,石英片检测试样两端的应力均匀性,获得微弱的透射信号。对开始加载阶段径向惯性效应带来的轴向应力附加值给予了计算修正,得到了肌肉在不同加载方向和不同应变率下的应力应变曲线。结果发现:肌肉材料的应力应变曲线呈现粘弹性材料所具有的凹向上特征,由最小显著差数法进行统计分析,发现猪后腿肌肉的力学性能对应变率和加载方向都敏感。沿纤维方向压缩时肌纤维易发生压缩失稳,强度比垂直纤维方向低。

The conventional split Hopkinson pressure bar （SHPB） has some limitations when the specimen is soft tissue. The modifications are necessary to ensure the reliability of SHPB experiment which is based on one-dimensional and uniformity assumptions. Pulse shapers were used to achieve stress equilibrium in specimens and constant strain rates. The quartz crystal force transducers were introduced for checking the dynamic stress equilibrium and obtaining the stress signals. The additional axial stress induced by radial inertia effect at the beginning of the dynamic loading was subtracted with an equation. The stress strain curves for muscles were obtained at various loading directions and various strain rates. The results show that the stress strain curves is concave upward as a viscoelastic material. The least significant difference method is used to explain that mechanical properties of muscle are sensitive to strain rate and loading direction. The compressive strength along the fiber direction is weaker than that along the perpendicular direction because fibers are inclined to buckling when compression loadings are along fiber directions.