Advanced Materials Research Vols. 941-944

Abstract: Geometrically nonlinear model and numerical solutions of large deformation of imperfect functionally graded materials conical shell subjected to both mechanical load and transversely non-uniform temperature rise are given. The material properties of functionally graded shell are assumed to be graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. On the basis of geometrically nonlinear theory of shell, governing equations of the axi-symmetrical deformation are derived. Numerical solutions are obtained by using a shooting method.

Abstract: This paper presents a method for calculating the fatigue life of helicopter composite material blade with residual strength theory. Builded the residual strength model, analyzed the influence of loading sequence, tensile -- compressed between the conversion and failure probability, adopt corresponding treatment plan. Using the model of residual strength, selected 19 typical flight condition, using the "rain flow counting method" load matrix, finally get the helicopter load spectrum. The composite blade dangerous section are calculated (root maximum strain), combined with every moment and centrifugal force, the flight state determined blade the stress spectrum, then according to the blade model and material characteristic parameters were calculated, results show that the residual strength decreases with the increase of flight time, and the failure probability increased with the flight time increasing. By comparison, the calculation results and full size is consistent with the experimental results, which shows the calculation is reliable.

Abstract: The mechanism of injury and damage evolution of composite aircraft is complex, traditional methods fatigue test relies on a large number of structural durability test data, not only consume large, but limited applicability. In order to ensure the fatigue of composite structures validated statistically, this article describes the most common methods: Life scatter factor method, load enhancement factor method and ultimate strength method.

Abstract: Diatomite was used as the main material and sodium silicate as the alkali activating solution in this paper. Diatomite light-weigh material was made by chemical foaming method. Compressive strength, density and heat conductivity were used to measure its performances. Results showed that density, compressive strength showed a growth trend while coefficient of thermal conductivity showed the opposite trend with increasing rapid hardening cement and senior gypsum.

Abstract: Synthetic rubber serving as the surface material of the ping-pong racket has good elasticity and anti-friction. Material parameters such as the hyperelastic constitutive model of the synthetic rubber are some of the critical parameters related to the competition achievement of Ping-Pong. Especially, the certain surface material of the ping-pong racket may be beneficial to the certain way of the racketting technique. The material parameters’ change may change the elasticity, plasticity, and anti-friction of the surface which would affect the playing level of the athletes. In order to access the relation between the hyperelastic ability and the racketting strength, it is necessary to predict the mechanical response of the ping-pong racket to the different hyperelastic surface materials. A two-dimensional finite element model is developed to predict the mechanical response between the hyperelastic ability and the racketting strength due to the material parameters’ change of the synthetic rubber. The Mooney-Rivlin model is considered as the hyperelastic material model using ANSYS soft in order to simulate the ping-pong racket’s surface material precisely. The different surface material parameters must affect the surface stress or strain of the racket which may change the athletes’ achievement. The special batting technique may acquire the special hyperelastic materials parameters. The rule will be obtained between the hyperelastic material parameters and the stress distribution of the racket surface materials. The ability accurately predicting the mechanical response of the ping-pong racket surface will greatly help the ping-pong racket designers in determining the suitable racket to the particular technology’s athletes.

Abstract: Grind-hardening experiments of 40Cr steel were carried out on the external grinder, and the hardness and hardened-depth of the samples were measured and analyzed. Experimental results showed that the external grind-hardening was feasible and could take the place of high-frequency induction hardening. Moreover, dynamic temperature field was simulated and analyzed based on the finite element analysis, and the simulation results were in a good accordance with these of experiment values.

Abstract: Silicon wafer is chosen in this work for the study of hydrophobic coating with industrial coating bar, due to the wafer has the superior flatness. Various amounts of TS-720 hydrophobic nano-particles were mixed into ITRI hydrophobic agent (H.A.), and this liquid mixture was applied onto material surface by use of a coating bar. In this study, we added the TS-720 nanoparticle from 0 – 2.5 wt% with ITRI H.A. The contact angle is higher than 135^o, when we have 2.5 wt% TS-720 nanoparticle adding in ITRI H.A.

Abstract: In this paper, we present experimental measurements of slip length of deionized (DI) water flow on a silicon surface and a graphite surface by using atomic force microscope. The results show that the measured hydrodynamic drag force is higher on silicon surface than that on graphite surface, and a measured slip length about 10 nm is obtained on the later surface.

Abstract: To improve the wear resistance and anti-corrosion properties of the aluminum, the electroless plating Ni-W-Mo-P alloy on the aluminum is necessary. The influences of heat treatment and additives (stabilizers) on the porosity, deposition rate, corrosion current, corrosion potential, microhardness and wear resistance of electroless plating Ni-W-Mo-P alloy coating, were investigated using electrochemical methods, etc. The results show that the deposition rate and anti-corrosion properties of electroless plating Ni-W-Mo-P are improved when the stabilizers, including KI (1mg/L) and “KIO₃ (1mg/L) + Pb (Ac)₂ (1mg/L)”, are added into bath, respectively. In addition, the maximum hardness (902 HV) and good wear resistance of Ni-W-Mo-P coatings are obtained when heated at 400°C (1h). However, its corrosion resistance is worse. Its microhardness is also obviously improved after heated at 200°Cfor 6 h, and the microhardness reaches to 950 HV.

Abstract: In recent years, polymer had been used in various situations and its use was increasing year by year. However, weathering was a complex process in which UV light, moisture and temperature variations all contributed to the deterioration of polymer properties. This paper reviewed the aging study progress of polymeric materials in recent years and the research problems. The evaluation methods of aging and antiaging of polymer materials were described, concerning with experiments, determinations and pathways of aging and antiaging. A relatively elaborate synthetical evaluation system of aging and antiaging was established.