Strain-rate-dependent mechanical properties of the equine hoof wall.
Strain-rate-dependent mechanical properties of the equine hoof wall.
复制标题
马蹄壁的应变率相关的机械特性。
DOI：
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发表时间：
1996
影响因子：
2.8
通讯作者：
J. Gosline
中科院分区：
文献类型：
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作者：
M. Kasapi;J. Gosline
在不同加载速率下对完全水合马蹄壁进行了紧凑拉伸（CT）断裂、拉伸和三点弯曲动态试验，以确定蹄壁粘弹性对断裂韧性和拉伸参数的可能影响。在CT测试中使用四种十字头速率：1.7 x 10（-5）、1.7 x 10（-3）、1.7 x 10（-2）和2.5ms-1;在拉伸测试中使用四种应变速率：1.6 x 10（-3）、3.2 x 10（-2）、0.33和70 s（-1）。最高测试速率的速度是使用大型定制的冲击摆实现的。弯曲测试频率范围为0.04 - 200 Hz。在CT试验中，初始模量Ei和应力强度因子K都随着应变速率的增加而增加（Ei从0.38到0.76 GPa，K从0.71到1.4 MN m-3/2），而断裂韧性参数J保持不变，为12 kJm-2。除极限应变外，所有拉伸参数对应变率都很敏感。Ei、总断裂能和最大应力分别随应变速率从0.28增加到0.85 GPa、从5.4增加到9.7 MJm-3和从17增加到31 MPa而增加。低幅动态试验的数据与CT和拉伸试验的Ei趋势一致。裂纹扩展的方向随着壁厚的不同而不同，其图案类似于三层。虽然扫描电子显微镜检查的断裂表面显示，随着应变速率的增加，伪延性行为减少，最终的拉伸参数受到积极影响，马蹄壁粘弹性不会出现妥协断裂韧性在高应变速率。
The mechanical properties of fully hydrated equine hoof wall were examined at various loading rates in compact tension (CT) fracture, tensile and three-point bending dynamic tests to determine possible effects of hoof wall viscoelasticity on fracture toughness and tensile parameters. Four cross-head rates were used in CT tests: 1.7 x 10(-5), 1.7 x 10 (-3), 1.7 x 10(-2) and 2.5ms-1; four strain rates were used in tensile tests: 1.6 x 10(-3), 3.2 x 10(-2), 0.33 and 70s(-1). Speeds for the highest test rates were achieved using a large, custom-built impact pendulum. Bending test frequencies ranged from 0.04 to 200 Hz. In CT tests, both the initial modulus Ei and the stress intensity factor K rose with increasing strain rate (from 0.38 to 0.76 GPa for Ei and from 0.71 to 1.4 MN m-3/2 for K), whereas the fracture toughness parameter J remained constant at 12kJm-2. All tensile parameters except ultimate strain were sensitive to strain rate. Ei, total energy to breakage and maximum stress rose with increasing strain rate from 0.28 to 0.85 GPa, from 5.4 to 9.7 MJm-3 and from 17 to 31 MPa, respectively. Data from low-amplitude dynamic tests agreed well with Ei trends from CT and tensile tests. Direction of crack growth differed through the thickness of the wall, the pattern of which resembled a trilaminar ply. Although scanning electron microscopic examination of fracture surfaces revealed a decreasing pseudo-ductile behaviour with increasing strain rate, and ultimate tensile parameters are positively affected, equine hoof wall viscoelasticity does not appear to compromise fracture toughness at high strain rates.