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991.
A method is presented to calculate the resistance of a high-speed displacement ship taking the effect of sinkage and trim and viscosity of fluid into account. A free surface flow field is evaluated by solving Reynolds averaged Navier-Stokes (RANS) equations with volume of fluid (VoF) method. The sinkage and trim are computed by equating the vertical force and pitching moment to the hydrostatic restoring force and moment. The software Fluent, Maxsurf and MATLAB are used to implement this method. With dynamic mesh being used, the position of a ship is updated by the motion of ??ship plus boundary layer?? grid zone. The hull factors are introduced for fast calculating the running attitude of a ship. The method has been applied to the ship model INSEAN2340 for different Froude numbers and is found to be efficient for evaluating the flow field, resistance, sinkage and trim. 相似文献
992.
The animal experiment of viscose carbon fiber based C/C composites applied in bone defection intramedullary fixation was carried out in New Zealand white rabbits. The histological observation on the 100th day after surgical operation indicated that the experimental animals recovered well and the bone defect area was reconstructed by new bone trabecula. Immunohistochemical observation of leukocyte common antigen and macrophage suggested that intramedullary fixation materials did not induct any chronic toxicity reactions such as inflammatory reactions, macrophage reactions and formation of granulation tissue. The tissue compatibility of this material was excellent. Meanwhile, the impurity element species and the biological toxic element content of viscose fiber based C/C composites were determined by atomic fluorescence analyzer and inductively coupled plasma atomic emission spectrometry. The results reveal that there are few biological toxic elements in the viscose fiber based C/C composites and it can satisfy the constituent demands of surgical implants. 相似文献
993.
大跨劲性骨架拱桥外包混凝土浇注方案 总被引:3,自引:0,他引:3
以在建昭化嘉陵江大跨劲性骨架拱桥为研究对象,采用Midas Civil 2010建立拱箱的梁-板组合有限元模型,对该桥的外包混凝土施工过程进行计算,探讨不同的浇注方案对劲性骨架拱桥的受力及挠度的影响,并考虑施工过程中的稳定性,为同类型桥梁施工提供参考和借鉴。 相似文献
994.
995.
996.
一种基于整车道路载荷谱的低成本零部件结构耐久性试验方法 总被引:1,自引:0,他引:1
为提高零部件与整车结构耐久性能设计的相关程度,提出一种基于试车场实际道路载荷谱时频域转换及试验加速理论的零部件结构耐久性能试验方法,可满足自主开发中零部件结构耐久性能试验的高质量、低成本要求. 相似文献
997.
998.
A new solution to the inverse position analysis of the redundant serial robot is presented. The inverse position analysis
problem of the redundant serial robot is transformed into a minimization problem and then the optimization method is adopted
to solve the nonlinear least square problem with the analytic form of a new Jacobi matrix. In this way, the inverse solution
of the redundant serial robot can be searched out quickly under the desired precision when the positions of the three non-collinear
end effector points are given. The inverse position analysis of the 7R redundant serial robot is illustrated as an example
and the simulation results verify the efficiency of the proposed algorithm. 相似文献
999.
We present a numerical formulation for resin flow based on the concept of quasi-steady state situation at the flow front.
To be fit for complicated product shapes, we use the four-node unstructured tetrahedron mesh based on which the numerical
formulation of temperature and degree of cure is developed. The validity of our method is established in the case where flexible
meshes are used. The results show that the numerical procedure, tested on known data, provides numerically valid and reasonably
accurate predictions. 相似文献
1000.
大型桥梁施工力学研究 总被引:1,自引:0,他引:1
通过国内数座大型桥梁的施工塌陷事故及原因的分析,提出对大型桥梁施工过程中的力学计算问题应考虑的主要问题(施工阶段力学计算的不确定性、支架拆除顺序、结构体系转换、准确选定荷载组合分析结构内力和局部应力),以及在施工监控中应该加强和进一步提高的方向,从而避免施工事故的出现. 相似文献