Applied Mechanics and Materials Vols. 117-119

Abstract: Product with low cost, lightweight and enhanced mechanical properties were the main reasons welding dissimilar materials thrived by most of the industries. The laser welding technique which has high-energy density beam was found suitable of carrying this task. This paper attempts to investigate welding of AISI 304 stainless steel to AISI 1008 steel through Nd:YAG pulse laser method. The main objective of this study was to find out the weldability of these materials and investigate the mechanical properties of the welded butt joints. Peak power, pulse duration and weld speed combinations were carefully selected with the aims of producing weld with a good tensile strength, minimum heat affected zone (HAZ) and acceptable welding profile. Response surface methodology (RSM) approach was adopted as statistical design technique for tensile strength optimization. Statistical based mathematical model was developed to describe effects of each process parameters on the weld tensile strength and for response prediction within the parameter ranges. The microstructure of the weld and heat affected zones were observed via optical microscope. The results indicate the developed model can predict the response within ±9% of error from the actual values.

Abstract: In this study, Nd: CW CO₂ laser were used in LSA experiment on Steel C1045 with four different systems alloyed by Sub-Micron Ceramics, namely Ti+C, TiO₂+C, TiC, Ti+V+C. The high hardness alloyed coating was prepared on the surface of Steel C1045 adopting laser alloying process for the ideal reinforced effect of surface that we expect. The microstructures of the four different alloy systems were analyzed by SEM. The microhardness and the friction coefficient of these laser alloying layers were examined, then the abrasion resistance and the main wear mechanism were summarized. According to the experimental results, comprehensive properties of Ti+V+C system were the most excellent in all systems.

Abstract: Stabilized aggregate containing Special cement with desulfurization residue is characterized by long setting time, slight expansion, and retarded inducing strength, therefore, research was conducted on its performance. Research results show that when on 28d and compared with stabilized aggregate of PC 32.5 cement, the stabilized aggregate of special cement’s unconfined compressive strength increased by 17%, dry shrinkage energy anti-cracking coefficient by 78%, whereas resilient modulus and splitting strength indicated small changes, whilst the performance of special cement materials showed vast improvements through significant increases in the stabilized aggregate’s mechanic and shrinkage performances. The strength of stabilized aggregate from special cement containing desulfurization residue mainly comes from AFt, Ca(OH)₂ and the C-S-H gel formed in the hydration of the special cement and also with the continuing dissolution of CaSO₃. The resultant new phase of C₃A•CaSO₃•11H₂O is formed after the 7d hydration period. Desulfurization residue in cement consists of a significant amount of Ca(OH)₂, therefore, the alkali content in the hydration phase is maintained at a very high level, which affects the consistency of ettringite through the formation of higher-quality needle-like crystals during hydration, which in turn is beneficial to reduce the base material’s self-shrinkage capability and improve its anti-cracking performance. At the same time, stimulated by Ca(OH)₂-CaSO₄, the hydration of fly ash and ground granulated blastfurnace slag is also improved, which is advantageous for further improving the cement’s strength and anti-cracking performance at a later stage in the curing process.

Abstract: Architecture is one of the most element of urban composition.During urban renewal, how to follow the characteristics of mountain, how to respect for history and local culture, how to continue and inherit historical context of architecture is the purpose of this article.The article puts forward some measures of continuing and inheriting historical context of architecture from planning, creating of mountainous architecture, protecting and managing,etc.

Abstract: Based on the design conditions,the structure strength and modal analysis are carried on the impeller by One-way Fluid-structure Interaction technique in ANSYS Workbench platform. The results show that under the water stress, the maximum deformation occurs on the brink of the blade, the maximum equivalent stress occurs at the liner near the blade pressure surface, the deformation of the blade has a great influence on the vibration of the pump.

Abstract: Uni-axial quasi-static tests at strain rates 10^-5, 10^-4, 10^-3,10^-2 and 10^-1 s^-1 and dynamic compressive tests at strain rates 1679, 2769,5000 and 8200 s^-1 have been carried out to study the mechanical behavior for polycarbonate used in the avigation industry. The stress–strain curves of polycarbonate in the strain-rate range from 10^-5 to 8200 s^-1 have been obtained. The effects of the strain rate on yield phenomenon and rate-dependent mechanical behavior are discussed. A plastic flow law based on the DSGZ rate-temperature-dependent constitutive model was used to describe the mechanical behavior of polycarbonate in the strain-rate range from 10^-5 to 10³ s^-1. The results at the six strain rates are in excellent agreement with the experimental data, which illustrates that the constitutive model can describe the mechanical behavior for polycarbonate at low and high strain rates perfectly.

Abstract: A basic 3D Cosserat continuum theory and corresponding finite element formulations are deduced. The deflections of a cantilever beam are analyzed by the 20-nodes solid elements based on the classical continuum theory and Cosserat continuum theory respectively. Compared with analytical solution brought forward by Timoshenko and Goodier, it illustrates that the numerical results based on Coseerat FEM are effective and more accurate and closer to the analytical solutions by choosing an appropriate value of the characteristic internal length, which also testifies the capability of reflecting the intrinsic property of the cantilever beam.

Abstract: Saturated and unsaturated seepage analysises are given for Dashiban Landslide applied multi-day rainstorm once in hundred years including three day and five day and seven day rainstorm. The impaction of rainstorm on the stability of landslide is discussed.

Abstract: The deterministic analytic stress formula of double-Layer pressure vessels is derived. The optimum radius ratio between the inner and outer layers is obtained under uniform safety margins. Based on that, the method for evaluating the fuzzy stress and strength reliability is presented and an application example is given. The investigation provides a reference for further studies of uncertain mechanical problems of multi-layer pressure vessels

Abstract: The motion equations of anisotropic media, coupled to the mass conservation and thermo-equilibrium equations of fluid, are studied here based on the standard space of physical presentation for consolidation of anisotropic saturated soils, in which a new compressible thermo-elastic model is induced. A set of uncoupled equation of elastic waves in anisotropic saturated solids is deduced. The results show that the elastic waves and speeds of elastic waves is affected by both anisotropic subspaces of solids and thermal and compressive coupling coefficients between fluid and solid. Based on these laws, we discuss the elastic wave behaviour for isotropic solids.