Applied Mechanics and Materials Vols. 152-154

Abstract: Computer simulation of cylindrical shell subject to lateral impact by rigid projectile is carried out. The effects of three kinds of typical rigid projectiles, geometric parameters of cylindrical shell and constraint conditions on critical speed are analyzed. The results indicate that the shape of projectile and size of cylindrical shell have a great influence on penetration, and the tapered projectile has a minimum critical speed. The influence of constraint conditions on penetration has a great relationship with thickness of cylindrical shells; energy distribution varies with different thickness of cylindrical shells.

Abstract: Many engineering materials exhibit different elastic properties under the extension and compression. Among these materials, the concrete is a typical material which has different extension modulus and compression modulus. Based on different modulus theory, mechanical analysis was performed in this paper for reinforced concrete beams, stress formula was deduced, and the corresponding formula was applied to concrete structures with second-class crack control, which has improved the original crack control conditions in the code for design of concrete structures in China based on the classical modulus theory.

Abstract: The structure and operating principle of rolling movable teeth reducer are introduced in this paper. The model of roller movable teeth reducer is established by Pro/E software , and the statics and modal analysis is made by ANSYS[1 2] software. The simulation results show that the loaded components of roller movable teeth reducer tallies with the theoretical computation and verify the mechanical characteristics of virtual prototype. Through modal analysis of Roller movable teeth reducer transmission Parts, such as the center wheel, roller movable teeth, the shock wave, and retainer, the vibration characteristics frequency of the roller gear reducer is obtained. This can avoid the working band of large deformation of bending and torsion It provides a basis for the optimization design and engineering analysis of reducer[2].

Abstract: In this study, A PLLA/silane modified chitosan fiber composite scaffold was sucessfully prepared using thermal induced phase separation method. The PLLA was chemically coupled with chitosan fiber surface using γ-methacryloxypropyl-trimethoxysilane.The composite scaffold had a nano-fibrous PLLA matrix (fiber size 200-750 nm), an interconnective pores ((1-6 μm), high porosity (>90%). Introduced surface modified chitosan fibers into PLLA matrix, it significantly enhanced the nano-fibrous scaffold. The new nano composite scaffold is potentially a very promising scaffold for tissue engineering.

Abstract: The UNS R56400 is a Titanium alloy commonly used in the aircraft industry. This alloy can be processed by machining depending on its final application. Drilling and turning are the most usual machining processes for working this alloy. Aerospace requirements involve high quality levels and, if possible, an on-line monitoring in order to preserve the workpiece design conditions. The machining process can be monitored by different methods. One of the most single methods involves the analysis of the finishing quality of the workpieces. This analysis is usually related to micro and macro geometrical considerations. In this paper a study of the finishing quality of dry turned UNS R56400 Ti alloy has been achieved. This study has been carried out based on the analysis of straightness and parallelism deviations as functions of cutting parameters, such as feed and cutting speed.

Abstract: In this paper, we investigate the motion of variable rope length pendulum as basic part of a portal crane. Our starting point is a discussing the behavior of that system for variable range of condition. We show the basic control strategy that damps the oscillation of hanging pendulum. This control law is developed using Lyapunov's method and recently analyzed by [2]. Further, the control strategy is improved in the sense of faster damping resulted from differential geometry.

Abstract: The Yellow River silt is a kind of sedimentary sandy soil which comes from the loess plateau carried by the steam of Yellow River. In order to utilizing silt and saving resource, investigation and analysis of characteristics Yellow River silts from the lower reaches area were performed, and clay-based cementitious material were prepared from Yellow River silt as main raw material, and a few of cement, lime and excitant agent as auxiliary materials. The mechanical properties and water resistances of clay-based cementitious material were studied. The results shows that: The clay-based cementitious material which is activated by composite excitant agent composed of sodium hexametaphosphate, calcium chloride and sodium silicate, have favorable mechanical and physical properties, especially favorable water-resistance. The specimen compressive strength is 21.2MPa after curing for 28d and with a softening coefficient 0.78, which cement content is 10% and excitant agent content is 4%.

Abstract: For cotton/linen fibers, yarns and other textile raw materials have natural weak points such as rough, easy to wrinkle and shrink, poor dyeability and so on, which are bad for clothing, this paper develops a lattice distortion modification processing technology of cotton/linen fibers and yarns, including the modification equipment and the process flow. After processed by this new modification technology, the performances of cotton/linen fibers and yarns, like softness, smoothness, fluffiness and dyeing properties improved significantly, which meet the product's quality requirements. Therefore, this lattice distortion processing technology can be popularized as a basic technology in the textile field.

Abstract: In order to test whether the crystallinity and orientation of ramie fibers have changed after they are treated by the lattice distortion modification processing technology, this paper does some experiments on it. Firstly, process ramie fibers by the lattice distortion modification processing equipment. Then use X-ray diffraction method to determine the crystallinity and orientation of pristine and modified ramie fibers. Finally analyse the effect of lattice distortion modification processing on the lattice structure of ramie fiber. The experimental results show that the lattice structure of ramie fiber has changed after modification processing, with crystallinity, grain size decreasing obviously and orientation slight descent, which make ramie fibers appear softer and more puffy from macrocosmic perspective.

Abstract: High temperature tensile test was conducted to study high temperature properties of the magnesium based composites reinforced with SiC particulates and monolithic magnesium as well. It was found that tensile strength of monolithic magnesium and Mg-SiC composites decreased with an increase in testing temperature. While the elongation to failure both samples were increased when increasing temperature. At all testing temperature, the tensile strength of the composite sample was found to be superior compared to monolithic magnesium due to presence of SiC particulates and efficiency of spark plasma sintering process in fabrication of the composites.