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利用力学原理对金属圆弧拱型波纹屋顶屈曲破坏位置进行了分析,求得一种简化计算的方法。其简化计算结果与试验和有限元计算结果进行对比验证,得出了一些结论。这些结论可为此类大跨度金属圆弧拱型波纹屋顶的设计计算、加工制作等提供有益的参考。 相似文献
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层状岩石中井孔稳定性的数值分析 总被引:3,自引:2,他引:1
如何保持复杂地层中斜井或水平井井孔的稳定。是油气田钻井和生产期间的重要研究课题。从横观各向同性本构模型出发,考虑岩石拉伸强度的方向性以及层状岩石中存在剪切强度薄弱面(如节理、断层、岩层界面等),在广义平面应变假定条件下,提出了一种可以分析任意走向层状岩石中井孔稳定性问题的二维有限元数值计算模型和计算方法。对复杂地质构造的层状岩石中井孔稳定性的二维有限元数值计算表明,岩层中薄弱面上出现的剪切破坏是导致井孔失稳的主要原因。对于特定的地质条件,用该模型可以快速预测现场钻井时的安全钻井压力,也可以分析和显示井孔周围破坏区的形状和范围。图4表1参10 相似文献
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The penetration behavior and perforation characteristics of Kevlar/Epoxy laminates with various thickness in quasi-static and ballistic perforation penetrated by steel projectiles with different noses are investigated. Quasi-static tests are conducted on MTS810 testing system. The results indicate that global deformation is the major mechanism of energy absorption and woven laminates exhibit larger energy dissipation than that of angleplied laminates. Therefore, the woven laminates have better quasi-static penetration resistance. Ballistic tests with velocity of 200 - 700 m/s are executed by using a powder gun with 7.62 mm barrel. Comparing ballistic experimental results with those under quasi-static condition, both the perforation performance and the failure modes are related closely to the speed of penetrator. Quite different from quasi-static tests, ballistic tests indicate that thick angle-plied laminate targets are even better than woven laminates in resisting ballistic impact. It is observed that the damage zone of the laminate is localized highly with the increasing of the impact velocity and correspondingly, the failure modes are more manifold. The shape of projectile noses affects the impact resistance of laminated Kevlar significantly in the range of velocity around the ballistic limit. 相似文献
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本文以泡沫陶瓷的静、动态力学性能为研究目的,针对其吸波耗能作用明显、抗爆能力强、工程应用潜力较大的特点,对一种新的粘土质闭孔泡沫陶瓷开展了准静态一维应力压缩实验、一维应变压缩实验以及动态一维应力压缩实验。得到该材料在三种加载条件下的应力-应变曲线,讨论了不同加载条件下的材料的强度特性和变形破坏特征。结果表明:(1)泡沫陶瓷属于应变率敏感材料;(2)虽然泡沫陶瓷的弹性极限不高,但峰值应力过后,强度并没有立即消失,而是维持在一定的应力水平上;(3)不论是动加载还是静加载,泡沫陶瓷的极限应变都很大,与孔穴压实相关的变形不可逆过程所导致的能量耗损十分可观,材料的吸波耗能效果突出。因此泡沫陶瓷可以作为防护工程中抗爆抗冲击构件的首选材料之一。 相似文献