Applied Mechanics and Materials Vol. 470

Abstract: For the unique geological features in Haita area, we optimized the synthesis conditions of slurry fluid loss additive ZJK103 and evaluated its performance. The experimental results showed that under different water conditions, water quality had no effect on fluid loss of ZJK103; The fluid loss additive had no adverse impact on compressive strength of cement stone; With same mixing water and different conserving water, the compressive strength did not change much. ZJK103 had better thickening effect than other average fluid loss additives. According to the performance of slurry system, the indoor synthetic slurry filtrate reducer could meet the quality requirements of Haita region cementing.

Abstract: Carbon-Carbon composite material is widely used as the thermal protection systems (TPS) of hypersonic vehicles for its special mechanical and heat-proof capabilities. The thin-walled structures with this kind of materials would exhibit large displacement response under high-level acoustic loads. Usually, the external heating is non-uniform. In the paper, a finite element model for analyzing nonlinear random dynamic behaviors of Carbon-Carbon composite panels with temperature gradients under Guassian sound excitation is founded. The total system response is decomposed into the time-independent component and the time-dependent component, using the equivalent linearization technique. Numerical results include root mean square (RMS) values of maximum deflections, time histories and power spectrum densities (PSD) of the deflection response. The results obtained in this paper can contribute to the thorough understanding of thermo-acoustic response of composite thin-walled structures.

Abstract: This paper is aimed to study the vibration isolation and thermal insulation of the polystyrene-filled sandwich panels with cross-shaped ribs. Based on Blochs theorem, band structure of the sandwich panels can be obtained by Comsol Multiphysics software. According to the Fouriers law and the minimum resistance law, the equivalent thermal resistance can be calculated both numerically and theoretically. The studies show that this periodic sandwich panels exhibit a good performance on vibration isolation and thermal insulation.

Abstract: With the rapid development of the economic construction in loess region, a large number of cutting slope excavation engineering were done in order to pioneer more construction space. The safety of this kind of project is worrisome because the scale of excavation is increasing and the cutting height of slope is rising. A high slope in Yan’an is selected for typical case and the stability of the slope is calculated by GTS software. The process of the deformation and destruction are analyzed and predicted from the relationship between the stress and the strength of the most dangerous slip surface. The research results can not only services in the engineering construction directly, but also play a guiding role to engineering construction in the loess region in China.

Abstract: The aim of this paper is in determination of nail bearing capacity in single-shear 4-nails joints of timber-cement boards of selected thicknesses bonded with middle solid wood (spruce) element on the base of destructive laboratory testing according to valid standards [1, 2]. The article also includes comparison with bearing capacity calculated according to Eurocodes [.

Abstract: A series of wind tunnel aerodynamic experiments were conducted to investigate the wind loads on the water tank located around the roof top of low-rise buildings with gable roof. There are two installation conditions discussed in this study, they were the alignment of tank and the location on roof. The result shown, the vertical tank might suffer less wind loading at each wind attack angle due to its symmetric shape. And the horizontal tank would have large wind loading in some approaching flow angles, especially in the 45 degrees attack angle the wind loading may reach its maximum. The variant location and roof slope were checked for the water tank installation, the results shown that the tank which installed at ridge region will suffer higher wind loadings and the border region of roof will be the recommended region for water tank installation.

Abstract: Existing non-seismically detailed low-rise RC buildings have higher seismic risks that are dependent on their seismic capacities and demand of building sites. Seismic risk analysis can be performed considering probabilistic characteristic of the structural damage. Structural damage is more accurately quantified by the damage indices than by a single engineering parameter. This study carries out comparative seismic risk analysis of a prototype building with and without metallic energy dissipating devices. Based on the probability distribution of damage index, it is demonstrated that the application of well-designed MEDDs to low-rise RC building can reduce its potential seismic risk.

Abstract: Damage resistance behaviors of CCF300/5428 laminates under five levels of impact energies have been researched by using progressive damage method. The progressive damage models (PDM) are composed of 3D finite element models, Hashin-type failure criteria and Camanhos degradation rules. The impact procedure has been simulated by the progressive damage analysis with user defined subroutines which have been developed and embedded into the general finite element analysis package. The history curves of the contact force and the impact point displacement are plotted. The global damage at typical events for various impact energies is investigated.

Abstract: Low velocity impact tests were carried out on T300/QY8911 and CCF300/QY8911 composite laminates, which led to similar impacted damage characterized by dent depths on laminates. Compression/compression fatigue strength tests of the impacted laminates were further conducted. The comparison of the compression/compression fatigue performance between the two types of composite laminates with similar impacted damage shows the compression/compression fatigue behaviors of T300/QY8911 and CCF300/QY8911 are similar. It follows that the CCF300/QY8911 is an effectively alternative to the T300/QY8911 in damage tolerance behavior.

Abstract: To illustrate the changes of important components during progressive collapse, this paper sums up the judgment method for important components. Based on the alternate path method and the concept of sensitivity analysis, we determine the key component of a RC frame structure. Then the changes of important components during progressive collapse are given. The results show that the location of key components changing with the structure damage in the process of progressive collapse.