The mechanics of compressive kinking in unidirectional fiber reinforced ductile matrix composites

Three distinct stages of kink band formation and propagation exist in ductile matrix composites subjected to compressive loading. These stages are called incipient kinking, transient kinking and kink band broadening. Each stage involves a different deformation mode. The mechanics governing each stage are discussed. Incipient kinking, where the peak load is attained, and kink band broadening, where the load attains a steady-state, are important in structural design. Two design philosophies are presented. References to pertinent literature are made throughout.     

反向凝固法生产H90-钢-H90复合带

研究H90-钢-H90反向凝固复合过程中复合层厚度的变化规律以及复合带的组织和性能，探讨界面结合机理。结果表明：随着浸渍时间的增加，复合层的厚度变化经历了凝固生长、平衡相持和回熔3个阶段，钢带的预热温度越低，获得的最大复合层厚度越厚；H90复合层的组织为等轴晶粒，复合界面处Cu和Fe发生了扩散，而Zn未发生明显扩散，扩散层较薄，约为4μm；复合带的界面结合牢固；不同复合层厚度的复合带，其力学性能略有差异，但均达到GB5213——85所规定的F级深冲钢板的力学性能要求。     

不锈钢精密薄壁件外表面磁力研磨工艺研究

磁性研磨是一种利用磁场中的磁性磨料,对具有相对运动的工件表面进行光整加工的新技术。选择铝、镍、钴磁粉作为磁性磨料时,对奥氏体不锈钢精密薄壁件外表面具有良好的研磨作用。     

喷气纺纱质量影响因素探讨

简要分析了半制品质量对喷气纱强力和条干的影响，着重探讨了喷气纺纱机喷嘴压力、牵伸比、集合器宽度等对成纱强力和条干的影响。试验证明，提高半成品的质量、制定适宜的喷气纱工艺是改善成纱强力和条干的关键。     

Reticulated Porous Multiphase Ceramics with Improved Compressive Strength and Fracture Toughness

A multiphase reticulated porous ceramic (RPC) as Si₃N₄–Al₂O₃–SiO₂ was fabricated by replication techniques. Proper volumes of additives and twice sinter- twice immerse process endow the RPC an excellent crack healing and submerging property. The compressive strength and fracture toughness improved owing to the crack bridging behavior. The existence of pores in struts in RPC blunt the crack tip and increased the external force needed to propagate the crack. The mechanisms play a beneficial role in enhancing the compressive strength and fracture strength. Si₃N₄ RPC with additives of 5%Al and 5% Al₂O₃ yielded the compressive strength of 9.8 MPa and fracture toughness of 0.3 MPa m^1/2.     

混凝土浇筑质量对钢管混凝土性能的影响

着重阐述钢管与其核心砼粘结强度对钢管砼承载影响问题 ,并介绍三种常用浇筑方式和检测方法。     

W-Cu材料室温强度和组织均匀性的影响因素

用浸透法对孔隙度为12%～17%的烧结钨进行了渗铜试验 ,研究了影响低铜含量的W -Cu材料室温бb及渗铜组织均匀性的因素 ,研究结果表明 ,铜对钨骨架的强化和韧化机制对提高W -Cu材料的室温бb 有重要作用 ;钨骨架具有合适的孔隙度是W -Cu材料获取均匀一致的渗铜组织的重要条件。     

Strength of Metals at High Strain Rates

Results of metal testing in impact tension–compression and indentation are analyzed. As the analysis of these data demonstrates, the strength of metals increases greatly with strain rates and at moderate indentation rates. At high indentation rates, a decrease in the specific energy (per unit volume of a displaced material) necessary for the formation of a conical cavity was observed. The account of the effects of viscosity, temperature increase upon plastic deformation and its localization can be used to explain the above phenomena.     

弹药包装冲击强度试验方法的改进研究

介绍一种新的弹药包装冲击强度试验方法，应用该试验方法可以防止冲击强度试验时出现与期望值相反的现象。     

The concept of an endurance limit for adhesive joints

The effect of cyclic stressing on the strength of single lap adhesive joints has been studied and a considerable reduction in strength observed when the maximum stress exceeds about 40% of the ultimate tensile strength, but whether or not a true endurance limit exists is not proven. Fallacies are shown in some of the techniques which have been proposed for studying the fatigue behaviour of adhesive joints.