圆织三维管状碳纤维复合材料弹性性能预测

为给圆织复合材料的工程应用提供参考依据,建立适当的单元胞体力学模型来预测其工程弹性常数。该模型采用跑道型纤维束截面假设,基于可设计几何参数和单元胞体的组织结构,合理预测了圆织三维管状复合材料纤维体积分数和弹性常数。并采用有限元方法对该模型进行了拉伸载荷下的力学分析,合理确定了复合材料的应力分布。结果表明,采用有限元方法所得的预测值与理论计算数值具有很好的一致性,证明了细观几何模型以及弹性常数分析方法的正确性。     

斑点叉尾鮰鱼丸弹性的研究

通过添加魔芋精粉、马铃薯淀粉及蛋清三种辅料以提高斑点叉尾鮰鱼丸弹性及感官品质。采用单因素实验分别考察了三种辅料添加量与鱼丸弹性及感官品质的关系,再采用正交实验确定三种配料的最佳配比。结果表明:魔芋精粉2.5%、马铃薯淀粉7.5%和蛋清4.5%添加到鱼丸中,鱼丸弹性及感官综合品质最佳。     

并条胶辊牵伸工艺性能浅析（一）

为更好控制并条工序重量、条干、纱疵、纤维伸直度、棉结等,生产实践表明,应用WRC系列并条胶辊在提高胶辊动态弹性基础上,具有高速度、耐高压、高耐磨、高抗绕、由高硬度趋向中硬度发展等特性。从优选WRC系列并条胶辊试验,优选工艺提高纤维伸直度减少棉结,纵横融会贯通防止长粗节、长细节纱疵等3个方面进行分析,认为牵伸工艺不合理、...     

A Two-dimensional Stress Analysis and Strength of Single-lap Adhesive Joints of Dissimilar Adherends Subjected to External Bending Moments

The stress distributions of single-lap adhesive joints of dissimilar adherends subjected to external bending moments are analyzed as a three-body contact problem by using a two-dimensional theory of elasticity (plane strain). In the analysis, dissimilar adherends and an adhesive are replaced by finite strips. In the numerical calculations, the effects of the ratio of Young's moduli of adherends, the adherend thickness ratio and the adherend length ratio between dissimilar adherends on the stress distributions at the interfaces are examined. The results show that the stress singularity occurs at the ends of the interfaces, and its intensity is greater at the interface of the adherend with smaller Young's modulus. It is also noted that the singular stress is greater at the interface of the thinner adherend. It is found that the effect of the adherend length ratio on the stress singularity at the interfaces is very small. Joint strength is predicted by using the interface stress and it was measured by experiments. From the analysis and the experiments, it is found that the joint strength increases as Young's modulus of adherends and the adherend thickness increase while the effect of the adherend lengths on the joint strength is small. For verification of the analysis, a finite element analysis (FEA) is carried out. A fairly good agreement of the interface stress distribution is seen between the analytical and the FEA results.     

TPI/HVBR/SBR共混物的性能

对高反式－1，4－聚异戊二烯（TPI）／高乙烯基聚丁二烯橡胶（HVBR）／SBR共混物的综合物理性能和动态力学性能进行研究。结果表明，共混物中TPI／HVBR／SBR并用比为10／20／70时，共混物具有较低的滚动阻力和动态生热及优异的耐屈挠疲劳性和耐磨性，与TPI／SBR（并用比为30／70）比较，其抗湿滑性提高（0℃时的tanδ值增大76．3％）。在SBR用量为70－50份，TPI用量为15－25份和HVBR用量为15－35份范围内，共混物具有良好的综合性能，滚动阻力和抗湿滑性获得平衡，同时具有优异的耐磨性和耐屈挠疲劳性，是高性能胎面胶料的较理想配合。     

基于广义Leontief函数的峰谷分时电价用户响应研究

基于广义Leontief函数建立了电价替代弹性模型,利用峰谷分时电价用户历史数据求解不同高峰时段电价替代弹性,并进一步分析了替代弹性和高峰时段时长与划分的关系。结果表明,高峰时段较短时替代弹性较大,说明用户对电价响应较好,随着高峰时段的延长,替代弹性下降比较明显,实例亦验证了替代弹性与高峰时段划分的相关性。     

裂纹转子的实验研究

对刚支裂纹转子、具有弹性支承的裂纹转子、刚支无裂纹转子以及具有弹性支承的无裂纹转子的振动特性进行了实验研究。研究表明：刚支裂纹转子和具有弹性支承的裂纹转子均发生分数次共振现象,且增加支承弹性有助于减小谐波共振。     

Three-dimensional transient analysis of FGM cylindrical shell subjected to thermal and mechanical loading

In this article, transient analysis of functionally graded material (FGM) cylindrical shell subjected to thermomechanical load is performed. Mechanical and thermal properties of the shell are assumed to be graded in radial direction according to power law distribution. In the case of simply supported edge condition, problem is solved analytically using Fourier series expansions for stresses and displacements along the axial direction and state space technique along the radial direction and Laplace transformation technique for time domain. For other boundary conditions, we use a semianalytical method by applying differential quadrature method along the axial direction and the state space method along radial direction. Accuracy of this approach is validated by comparing the results with the results reported in the literature. Moreover, influence of edge boundary conditions, length to mid radius ratio, FGM direction and time on stresses, and displacements is studied.     

未来我国石油供需矛盾及其解决对策

我国对石油的需求持续攀升,而国内石油产量一直保持缓慢增长,导致石油对外依存度逐年上升。假定未来我国石油消费量等于石油需求量,国内生产总值每年以7.177%的速度增长,石油需求弹性保持在0.5的水平,采用情景分析法、能源需求弹性法和时间序列法对我国未来几年的石油需求、供给进行预测。预测结果表明,我国未来几年石油供需缺口将越来越大,2020年会达到约3.9×108t,形势很不乐观。鉴于此,建议首先要立足国内,鼓励低品位石油资源开发,保障石油基本供应;其次要放眼海外,调整战略重点,弥补我国石油供需缺口,三大石油公司应在稳定中亚、非洲市场的基础上,大力进军南美、中东和亚太市场,加强海外油气合作,实现海外规模化经营;同时要调整能源结构,发展清洁能源,缓解国内石油供需矛盾;另外要提高能源使用效率,减少能源整体需求;还应该循序渐进、有计划分阶段地建立适合我国具体情况的完备的战略石油储备体系,并尽快出台石油储备法。     

高层建筑多层地下室的动力分析

将高层建筑多层地下室及桩简化成部分埋置于弹性介质中的质点串来处理,应用弹性地基上梁的某些结果,结合上部质点串柔度系数的计算方法,求得了整个结构的柔度矩阵;并应用Stodola迭代法与降阶法计算了结构物的固有频率,为工程设计人员提供了参考依据。