Applied Mechanics and Materials Vol. 248

Abstract: This research is devoted to the decision of a problem of modeling the wear process of concrete. In paper presents a wear model of concrete as heterogeneous material on the basis of the theoretical and experimental contact mechanics methods approach. The model predicts that its abrasion strength depend on physical and geometrical characteristics of cement matrix and aggregate. The theoretical modeling of a surface with the strengthened ore softening areas is applied to optimization of concrete structures. The experimental results support these theoretical predictions.

Abstract: In order to reduce or avoid the damage of the composite parts in the service process and failure, This study applied db5 wavelet processing and multi-scale(5 layers) analysis to the denoised signals from carbon fibre reinforced composite material. Through repeated verificationput, put forward a fast and accurate method for estimating damaging degree. the advantage of this method is preventing component failure, and this method is proved effective.

Abstract: A square grid sandwich plate is modeled as a laminate plate in this paper, and the equivalent method is proved according to natural frequencies of the grid sandwich plate and the equivalent plate. Effects of geometric and material parameters on the equivalent Young’s modulus, equivalent thickness, and equivalent density are discussed and some conclusions are obtained:(1) effects of thickness of upper and lower panels on equivalent parameters are the same; (2) keeping the total thickness of upper and lower panels a constant, the equivalent thickness reaches its maximum while thickness of upper panel is equal to that of lower panel, meanwhile the equivalent Young’s modulus and equivalent density get to their minimum values; (3) the equivalent thickness and density increase with thickness of grid sandwich core; (4) the equivalent Young’s modulus decreases while the thickness of grid sandwich core increases; (5) the equivalent Young’s modulus increases with that of the grid core; (5) the equivalent density is inversely proportional to the equivalent thickness; (6) the equivalent Young’s modulus is inversely proportional to the equivalent thickness. These conclusions are helpful to design square grid sandwich plate.

Abstract: Concrete setting and hardening designate the concrete grade. The impedance spectroscopy method, as one of the non-destructive testing method group, was used to characterize concrete specimens and track the changes in the concrete spectrum. Variances in the tan δ (f) and Im Z(f) or Re Z(f) of the specimens under investigation have been observed. The specimen quality has been described by means of the loss type prevailing in the material. The results of this study are expected to provide information about the correlation between the n-factor and the concrete setting time.

Abstract: Considering the non-linearity, complexity and anisotropy of constitutive equations in composite materials, numerical methods are essential to evaluate the behaviour of this material. The finite element method (FEM) is a powerful computational technique for the solution of differential and integral equations that arise in various fields of engineering and applied science such as composite materials. Here, an FEM tool is designed to analyse non-linearity in the behaviour of composites caused by the effect of transverse shear and twist in laminated composite plates. The tool is established by using FEM for composites in ABAQUS combined with programming in Python to run the tests for all possible fibre orientations in laminated composite plates. It is shown that the tool has the ability to design laminated composite plates by considering the effect of transverse shear and the tool’s output provides results for all different fibre orientations. It is demonstrated that there is good agreement between numerical results obtained from this tool and experimental results. The advantages of the tool give designers the opportunity to use this tool for wide range of products.

Abstract: Biaxial oriented PVC (PVC-O) pipes have great advanced properties: high intensity, high impact resistance, material saving etc. The new product can be used in many situations. There are more than three effect methods for manufacturing PVC-O pipes in foreign countries. Relevant researches have been preceded in some domestic institutes, but there are no effect processing methods and productive technologies have been reported. Based on plastics bulge forming and hop-pocket method, the quasi-dynamic continual expansion method (QDCE) is proposed in the paper. The key point of QDCE takes advantage of high elasticity、high compression ratio and high tear resistance of elastomeric materials, meanwhile designs production equipment and processing technology for manufacturing PVC-O pipes. We explore the mechanism of QDCE and design a whole package of expanding equipment.

Abstract: By using the computational fluid dynamics code, FLUENT, Numerically simulation is investigated for Youngshou power plant. Under the constant ambient temperature, the effects of different wind speed and wind direction on the thermal flow field are qualitatively considered. It was found that when considering about the existing and normally operating power plants, the thermal flow field is more sensitive to wind direction and wind speed. Based on the above results, three improved measures such as: increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively improving the thermal flow field, and enhanced the heat dispersal of ACC.

Abstract: The behavior of nitrogen into the dissimilar joining metal between AISI 304 and AISI 316L Austenitic stainless steel during gas tungsten are welding process was investigated. Studied by using an arc nitrogen atmosphere – controlling in chamber. The relations between nitrogen content of the dissimilar weld metal and the welding parameters, such as the welding current, welding speed, welding arc length and penetration area of weld metals were also evaluated. The results show that the nitrogen content of the weld metals decreased with an increasing welding current, and increasing penetration areas of weld metal, but scarcely depends on the welding arc length. The nitrogen content of the weld metals increased with the welding speed, but decreased penetration areas of weld metals. The role of nitrogen content on the dissimilar weld metals stainless steel is further confirmed by the experimental microstructure, mechanical and corrosion behaviour of the weld metal.

Abstract: A kind of processing strategy of total life cycle of mechanical products was designed. A logistics model of total life cycle of mechanical products was established based on eight typical states of life cycle of mechanical products. The logistics analysis of total life cycle of a sort of aero-engine was carried out by using the model. The dynamic equivalent quantity of the aero-engines in different states of life cycle was obtained when times changed from the products were first put into production to the time when stable production capacity was reached. The model can also be used to predict logistics of other products rapidly. The results give references for production departments or enterprises which use life cycle methods to configure their production resources effectively and optimize production processes, and also provide a basis for further analysis of total life cycle analysis such as economic and environmental assessment.

Abstract: An approach to optimize the cutting parameters based on Particle Swarm Algorithm(PSO) and Finite Element Method(FEA) was proposed. A cutting parameters optimization model was established whose design variables are the cutting parameters and objective function is to minimize the maximum deformation. PSO was used to optimize the cutting parameters and FEA was utilized to predict the machining deformation of the thin-walled workpiece. Finally, the entire technique was demonstrated in a case study. The simulation and experimental results show that the approach can be further employed into the practical machining situation.