Applied Mechanics and Materials Vols. 117-119

Abstract: Based on the axisymmetric thermal elastoplasticity theory, the reverse plugging of a Cu thin plate irradiated by ms-degree long pulsed laser is calculated by FEM. The temperature and stress data on typical position of the thin plate are obtained, and the space distribution of the all parameters is given. The FEM results, theoretical and experimental results are in good accordance with each other.

Abstract: Abstract. In this paper,the effect of rare earth La on microstructures and properties of ZA30 alloy were studied . The result shows that The structure is refined and mechanical properties are improved by adding La to ZA30 alloy,the alloy have best structures and comprehensive mechanical properties when La content is 0.1%; Rich-La phases are metallic compound Cu₂La,Al₂La and LaZn and precipitate in blocky form ,its number and size increase with La; The abrasive resistance of ZA30 alloy is significantly improved when La is over 0.3%.

Abstract: The modified equations for PC-Newmark method and OS (operator-splitting) method were derived, which could be applied to the numerical solution for the non-linear equation encountered in real time on-line test. The structure with FPS seismic isolation system was divided into three substructures, namely the FPS system, the experiment substructure and the computation substructure. The explicit algorithm is applied to the first two substructures and the implicit algorithm to the third one in order to loosen the stability limitation. The numerical solution for a 7 DOF structural model has proven the alleviation for stability requirement.

Abstract: This paper investigated the variation of dynamical response of a low pressure rotor in turbo-shaft engine with its system parameters. Based on the model of low pressure rotor, a dynamical simplified model of two-disk rotor with Squeeze Film Damper at each end was built. Its motion equations were derived. The numerical method was applied to solve the 12-dimensions differential equations. The influence of some parameters, e.g., rotating speed, eccentricity and its phase angle, mass ratio of two disks, were analyzed. From simulation results, it can be seen that when phase difference of two disks’ eccentricity is π, the two disks have their minimum vibration amplitude respectively. When their phase is identical, their vibration responses reach maximum values. The larger the mass of mid-span disk is, the larger the vibrations of two disks are. When mass of mid-span is lesser than that of overhung rotor, the response of system will decrease.

Abstract: This paper presents a series of uniaxial loading tests on the thickness-reduced steel plates bonded with carbon fiber reinforced polymer (CFRP) strand sheets using underwater epoxy as adhesive. Four sets of material test are carried out on epoxy coupons at different curing times. Repaired performance of CFRP-bonded steel plates is investigated in terms of initial stiffness, yield strength, and failure mode of the specimens. Test results showed that the structural performance of CFRP-bonded steel plates does not reach the expected design level due to a slow curing process of epoxy adhesive in this study. The curing effects of epoxy adhesive on the repaired performance are discussed.

Abstract: Using analysis methods of stretching test，SEM，EDS and microhardness test to investigate and research the mechanical properties, the fracture mechanism，the reacting phases are produced and the distribution range of vacuum diffusion bonding joints of Ti-6Al-4V/Cu/304. The results show that when bonding pressure is 5.0 MPa, the tensile strenght of the joint increases at first, but decreases with the increasing of bonding temperature and time, When bonding temperature is 1223K, bonding time is 3.6ks, there is a maximum tensile strength that is 163 Mpa. However, it will be disadvantageous to the performance of the joints, when bonding temperature and time extended overly. Using Copper foil as the interlayer, the intermetallic compounds did not generate in interface of Cu/304，Therefore, it formed multi-phase transition organizations by solid solution, intermetallic compounds in interface of Titanium alloy/Cu，such as Ti_xCu_y, Ti_xFe_y and so on. The effect of Ti_xCu_y on strength of the joints is slightly larger than Ti_xFe_y compound. The fracture mainly happened in the titanium alloy side Ti₂Cu intermetallic compound in region Ⅱfor the source dehiscence, developping inⅡ-Ⅲ area junction weak intermetallic compounds of diffusion layer. It is brittle fracture. Therefore, it is the main way to improve the joint strength by improving the interface structure of titanium alloy/Cu side.

Abstract: With China's urbanization process accelerated ceaselessly, construction developing rapidly, the great architectural waste discharge. At present, construction waste production but also has far exceeded the rate of domestic can bear. Meanwhile, the disposing mode, such as mechanical landfill and burned, resulting in huge waste of resources and environmental pollution. So how to efficiently processing and using reasonable construction wastes have become our country now faces a severe environmental and ecological problem. This paper discusses the causes, construction waste handling and processing components, the problems existing in the detailed analysis is introduced, and introduces some developed countries and regions with the application of construction waste disposal of the newest research achievement, and comparing and analyzing current construction waste comprehensive treatment of some problems existing in China, and finally puts forward some construction waste comprehensive reuse countermeasures.

Abstract: In this paper, the modal and the harmony response analyses of the stator of the bar-type piezoelectric motor are done by using the finite element method. The influences of the motor’s structural parameters and the voltage applied to ceramic plate on the characteristics of the stator are discussed. Some useful results are given. This provides theoretical basis for the structure optimization design of the motor.

Abstract: This study used the nanoindenter to perform indentation tests on copper bulk and nano copper film in order to discuss the mechanical properties of pure copper at the nano scale. This study tested 7 levels of load, ranging from 20 to 200 μN (load increment at 30 μN) for the indentation tests on copper bulk and nano copper film specimens. Results showed that the load was roughly proportional to the residual depth, in the case of flat nano copper film, while the relationship between the load and the residual depth was not significant in the case of unsmooth copper bulk. Moreover, the hardness of both the copper bulk and the nano copper film would increase along with increasing load, while the Er value change trends of both the copper bulk and the nano copper film specimens differed with increasing load.

Abstract: A square shaped silicon ingot was cast by cold crucible continuous casting. The grain growth behaviors during different growth stages were investigated. In the first, grains nucleate at the base surface in the centre and in the three phase junction at periphery, and then grow upwards and inclined upwards separately. In the second, grain grow competitively, two distinguished zones are formed. In the final, a cap is formed on the liquid free surface, and precipitates are present.