Papers by Keyword: Reinforcement Mechanism

Abstract: The mechanical behavior of polyethylene (PE) co-polymerized with polyhedral oligomeric silsesquioxane (POSS) was studied by using molecular simulations. Simulation configurations consisted of aligned PE chains with POSS attached to the central chain and amorphous PE chains with different content POSS. From the simulations with aligned PE chains with POSS, it was found that the method for reinforcement was due to dislocation pile-up at POSS, and above a critical stress the dislocations traverse the POSS causing a sawtooth variation in the load-displacement curve. The stress-strain curves for amorphous PE-POSS bulk showed distinct elastic and plastic straining stages. Plastic straining consisted of hardening and slipping segments attributed to dislocation pile-up and chain sliding. Computational results were used to develop a reinforcement model to describe the mechanical response of PE-POSS bulk under uniaxial tension.

Abstract: Dynamic compaction is one of the densification techniques of ground improvement and extensive theoretical, experimental and in-situ tests have been used to clarify its mechanism. In this paper, a literature review about the dynamic compaction is carried out and the emphasis is put on the reinforcement mechanism, effective reinforcement depth and influence range of vibration to give a reference for the ongoing researches of dynamic compaction method.

Abstract: CFG pile has been widely applied as one of the common ground treatment techniques. As a concealed work, the construction quality of pile foundation not only relates to the success of the project, but also concerns the benefits of thousands of households. Only strengthening the supervision and management during the construction and strictly designing and specifying CFG pile can ensure the construction quality of CFG pile. But most researches focus on operating mechanism and theoretical analysis, and there are fewer researches about the construction of CFG pile. The real construction of CFG pile has no specified operation and lacks of the construction guidance, which not only causes great problems and has great influence on the intensity of CFG pile, but also makes the real pile body have great difference from the design requirements. Therefore, the study on construction of CFG pile in the paper has great significance.

Abstract: Straight carbon nanotubes (CNTs) with radially-growing morphologies and long length were grafted on carbon fibers by catalytic chemical vapor deposition and they were used to reinforce carbon/carbon composites (C/Cs). Mechanical tests indicate that CNTs can increase the interlaminar shearing strength of C/Cs by about 200 %. The reinforcement mechanism was concretely discussed with emphasis placed on the change of the cohesion of pyrocarbon matrix.

Abstract: The bolt’s load transfer differential equation has established according the stress equilibrium in a small section of a bolt and load transfer mechanics. And according the rock mass deformation before and after bolt assembling, the rock bolt’s load transfer equation has gained. In this paper, from later researching achievement, the radial displacement function of brittle wall rock for tunnel is gotten. And combining the radial deformation of tunnel wall rock mass, the axial force and friction resistance of rock bolt have gotten in brittle wall rock mass. Through analyzing the stress distribution feature and stress distribution tendency and affection factors, the affection factors to anchoring results is the dilatancy angle. And through the studying, it is show that the axial force and shear stress of rock bolt are bigger with the dilatancy angle increase

Abstract: Based on the strength reduction method，the anchor reinforced slope has been simulated by elastic-plastic FEM. The safety factor of reinforced slope with anchor was gotten by heuristic search method. The plastic zone running through or not is taken as a standard to solve slope safety factor. The research results show better the distribution situation of stress and strain in slope. It proposes a new method to evaluate the stability of slope with complex boundary conditions. Taking a slope engineering for example, the stability safety coefficients of the slope are calculated when the slope is reinforced with anchors of different length. When the design length of anchor is longer than a certain value, the anchor length has little effect on improving the stability of slope and slope toe. Consequently, the reasonable design length of anchor is put forward

Abstract: The metallic glass particles reinforced aluminum matrix composites without obvious defects were obtained successfully by explosive compaction of mixed powders. The quasi-static compressive mechanical properties of the composites with the reinforcement matrix mass fraction 10%, 15% and 20% respectively were researched recur to universal testing machine of Instron 3367 and self-consistent theory. Finally, reinforcement mechanism of the metallic glass particles on the matrix was analyzed by numerical simulation recur to LS-DYNA program. The results show that the mechanical properties obtained by self-consistent theory are well accord with the experimental results; compared with pure aluminum, the yield stress of the composites with metallic glass particles reinforcement of the mass fraction 20% enhances 46.8 percent; the main reinforcement mechanism is the amorphous particles can undertake higher loading, the combined quality of the reinforcement particles with the matrix and the distribute uniformity of the reinforcement particles are important factors which will affect the reinforcement effects.

Abstract: This work aims to evaluate the effect of cotton stalk fibers with styrene acrylic emulsion treatment, slag and ordinary Portland cement on the properties of crops fiber/gypsum composites. The results show that crops fibers with surface treatment, slag and ordinary Portland cement can increase the bending strength and improve the water-proof property of crops fiber/gypsum composites obviously. The fracture surface of crops fiber/gypsum composites were observed by SEM, and the action mechanism of the crops fibers, slag and ordinary Portland cement on crops fiber/gypsum composites were discussed.

Abstract: This work aims to evaluate the effect of Kevlar fibers with chemical treatment on the flexural strength, compressive strength and impact resistance of cement mortar. The experimental results exhibit that Kevlar fiber with a larger percentage can increase the flexural strength and improve the impact resistance of cement mortar, and the reinforcement effect of Kevlar fiber with chemical treatment is more obvious. The surface morphology of Kevlar fiber and the fracture surface of cement mortar reinforced with Kevlar fiber were observed by SEM, and the reinforcement mechanism of the Kevlar fiber on cement mortar was discussed.

Abstract: Glass fiber reinforced polymer composites were prepared by dispersing zinc oxide (ZnO) whiskers in resin matrix. Static and dynamic tensile tests of the as-prepared composites were performed by means of a universal testing machine and the split hopkinson tensile bar (SHTB), respectively. Good tensile properties, which can be affected by the strain rates, of the composites are obtained. The fracture section morphology of the composites was investigated by scanning electron microscope (SEM). The different failure of the composites under static and dynamic tension is found. The tensile properties of the composites are dominated by pull-out and fracture of fiber bundles. The influence of ZnO whiskers on the performance of composites has been discussed. ZnO whiskers, which have unique three-dimensional structures and corresponding stress transfer, contribute to the tensile properties of the composites.