Applied Mechanics and Materials Vols. 52-54

Abstract: The finite element model of cross simulator including supporting structure, beam, etc. was set up in the environment of ABAQUS. After the static analysis which meets the requirements, the model’s dynamic characteristics when bearing impact load was obtained using explicit method according to modal analysis results. Comparing different analysis results with technical index, it indicates that larger impact load makes the dynamic characteristics worse significantly.

Abstract: Mechanical evolution of soymilk coagulation was investigated using a novel fiber optic sensor in order to solve the problem of instability in Chinese traditional tofu quality. The sensor signal was measured, and studied the effects of temperature, soymilk concentration, and calcium chloride solution concentrations on tofu making parameters. The scattering light ratio followed a sigmoid increase during soymilk coagulation. Tofu firmness, tofu moisture content, and tofu yield were predicted from the time to the maximum slope of the first derivative of scattering light ratio. The proposed mathematical model shows potential for on-line monitoring of soymilk coagulation.

Abstract: In this paper, process of how carbon-protection-film is formed and dynamic influence process of carbon-protection-film to electrode erosion are discussed in limited continuous pulse discharge. It is considered that the compensation of carbon-protection-film to anode erosion results in the cathode erosion bigger than that of the anode under long time EDM.

Abstract: Ink marking is a key process for die sorting of IC wafer manufacturing. Intensive production of wafer is urging the inkers for more rapid and more stable ink marking performance on surface of defective wafer dies safely. In this paper, a non-contact jetting dispenser is introduced to the wafer die marking. After presenting the mathematical description of dynamic fluid for 2-phase flow, numerical simulations are launched to reveal the characteristics of droplet generation and key factors are discussed. A jetting dispenser is developed and experimental results are analyzed. According to the simulative results and the dotting performance shown in experiments, the non-contact jetting dispenser is capable for wafer die marking in dotting efficiency and stability.

Abstract: The solidified microstructure and the modified treatment have been systematic studied for the low carbon high boron Fe-C-B steel. The cast solidified microstructures of the low carbon high boron steel are consisted of the matrix and the boride phases. The matrix phase is consisted of the ferrite, pearlite and a few martensite phases. The boride phases of the hypoeutectic steel are based mainly on the Fe2B phase. With the increasing of the boron content, the Fe2B phase is decreased. When the boron content is excess 2.6wt.%, the boride phases are changed from the single Fe2B phase to the compound structures. Meanwell, the morphologies of the boride phases are transformed from the long strip-shaped and the fish-bone reticular structure to the rosette type. The boride phases of the eutectic steel are mainly the M2B phase. However, for the hypereutectic steel, it are composed of the M23(C, B)6 and B0.7Fe3C0.3 phases. The suitable modifier for the hypoeutectic low carbon high boron steel is the compound modifier 0.2%RE+0.2%Ti. After modified, the reticular boride phases are disconnected. Moreover, there existed some of isolated massive borides. The appropriate modifier for the hypereutectic steel is the compound modifier 0.9%Nb+0.4%RE. After modified, the primary borides are fine refined and tend to round.

Abstract: The model of thermoelastohydrodynamic (TEHL) analysis of a transmission gear in a fuel cell bus was developed. The influence of rotating speed on the frictional pair was investigated numerically on the base of the mathematical model. The pressure field, the temperature field, the oil film thickness were calculated under different rotating speeds. It is shown that the worst lubrication in the tooth root occurs and the minimum film thickness increases with growth of the rotating speed. The temperature of lubricant is up to 140oC at 4000rpm.

Abstract: In order to improve the wear resistance of continuous casting crystallizer, Co-based alloy coatings were prepared on copper substrate by a pulsed Nd:YAG laser. Scanning electron microscopy, X-ray diffraction, microhardness and wear resistance testing were employed to study the microstructure and properties of the cladding coatings. The results show that the friction coefficient and wear mass loss of the cladded coating with the volumn ratio of Stellite X-40：TiC：CaF2=60：10：30 are both the smallest; the average microhardness of the cladded coating is 496.2HV0.2 which is about five times higher than that of the substrate.

Abstract: At present, the study of smart composite material of carbon fiber is mainly focused on the usage of the material pressure-resistant effect. The change of resistance reflects the force status of the structure and its performance mainly depends on the sensitivity of pressure-resistantance. Such composite’s sensitivity has a relationship with the sample preparation process. In this paper, the resin-based carbon fiber is improved so as to obtain a high sensitivity and good stability bundle of modified carbon fiber polymer-matrix composites. Clamp the samples of this material on the micro-tensile test table, the characteristics of mechanism pressure-resistant is analyzed by observing the fiber interface changes through SEM when loaded, combined with monotonic loading curve of the sample. With the electrical model of parallel circuit and normal distribution model and Weibull model, piezoresistivity model is established. Compared with the model curve and the experimental model, the mode is verified being a high accuracy.

Abstract: Three models were established in this paper to analyses the strength of intact, damaged and reinforced pressure hull of ocean structure. Linear elasticity and elastoplasticity FEA method were adopted. The results showed that replacing rib and local reinforcing damaged pressure hull could not restore the performance of pressure structure. Other methods must be considered.

Abstract: A pit with dimension 200mm×160mm×21mm is digged in the middle of steel plate using carbon-arc air gouging. The pit was polished and welded using CW66J welding rod. Built-in stress, toughness and rigidity was tested to validate the validity.