Papers by Author: Guang Ping Zou

Abstract: In 3-point bending fatigue experiments of sandwich plate with visoelastic core and steel faceplates, it is found that response loading of specimen is very sensitive to cycling frequency. From fatigue test, different loading response of sandwich beam obtained in various cycling frequencies. Based on viscoelastic theory, responses of deformation of sandwich plate in cyclic square load wave are calculated. And an explanation of influences of cycling frequency is elaborated.

Abstract: Some fundamental issues, such as stress wave dispersion effect, loss of contact, pulse shaping effect are still needed to thoroughly understand in Hopkinson pressure bar loaded fracture experimental techniques. In order to avoid the influence of stress wave dispersion on the analysis of dynamic experimental results, a computational procedure has been developed based on the combined analytical solution of Pochhammer-Chree with Fourier spectroscopy analysis. The validity of this proposed computational procedure was confirmed via the comparison with the experimental stress pulses obtained from pulse-shaped tests. The experimental results can be easily interpreted and the testing accuracy can be improved using this computational procedure.

Abstract: Through complex variables function, wave propagation of perforated thin-walled plates is deduced. And it is found out that the dynamical stress concentrates where the concentration parameter vertical to incident orientation is about 1.5, and with the increase of incident wave frequency, holes have less influence on the dynamical stress concentration during wave propagation. With the help of acoustic emission technique, holes do not have much effect on nondestructive test of acoustic emission.

Abstract: When the front end of the supercavitating vehicles subjects to very large axial non-stationary random excitation at high speed motion under water, it is necessary to analyze dynamic responses of supercavitating vehicles under non-stationary random excitation. The dynamical equation of supercavitating vehicles is transformed into the form of state equations. The Simpson integration method is going to calculate the integral term of the general solution of state equation to improve the precise integration method. The explicit expression of dynamic responses of supercavitating vehicles is deduced, the means and variances of structural responses are calculated with operation laws of the first moment and second moment. Under different sailing speeds and different cone-cavitator angles dynamic responses of supercavitating vehicles are given by the examples, and the effectiveness of the method was demonstrated.

Abstract: A modified Hill yield criterion considering tension-shear stress coupling was given and material parameters of nickel-based single crystal in this criterion was determined by the Least Square Method. Crack tip plastic zones of nickel-based single crystal plate were analyzed by using this modified yield criterion and the plastic zones corresponding to mixed mode I, II crack, were derived. The crack tip plastic zones of nickel-based single crystal were compared to that of isotropic material. The influences of tension-shear stress coupling, compound ratio of mixed mode I, II crack and temperature on crack tip plastic zones were discussed. The results obtained in this paper indicate that the increasing rate of crack tip plastic zones with compound ratio in the plane stress condition is greater than that in the plane strain condition for nickel-based single crystal and the temperature has greater influence on the size of crack tip plastic zones.

Abstract: Sandwich plate system (SPS) with polyurethane elastomer is more and more used on ship buildings as grillage. A Comparative Study on critical buckling loads between steel grillage and SPS stiffening plate are carried out in this paper. Plate elements and beam elements are used in numerical simulation and a rectangular model is taken as a calculating example. By using of FEA software ANSYS, ultimate buckling loads are calculated with different influential factors between steel grillage and SPS stiffening plate, including the number of stiffening ribs, inertia moment of stiffening ribs, and the thickness of plates. the analysis results of comparison shows that SPS stiffening plates have better performance than steel grillage under in plane compressive loadings.

Abstract: Based on Reissner’s sandwich plate theory, the critical globlal buckling equation of sandwich plate with ribs is deduced by energy method under simple support boundary conditions. And the critical buckling solution is obtained and discussed here. Afterwards a rectangular sandwich plate with steel faceplate and polyurthane core is taken as an example. The influence on critical global buckling stress with different inertia moments in rectangular sandwich plates are discussed. simularly the effect of the lengh ratio of two sides and the thickness of rectangular sandwich plate are also studied.

Abstract: The aim of this work is to investigate the fatigue behaviors of the steel honeycomb sandwich beams at 400°C through three point bending experiments. A stiffness reduction approach was adopted which was further based on the interpolation by the empirical functions of experimental results. For load control fatigue experiments, the evolution relations between number of cycles and displacement were obtained through real-time deformation monitoring of the specimens. A method based on exponential function fit was adopted in the further analysis, whose coefficients depended on the material properties, loading levels and high temperature conditions. This approach allowed us to predict the high temperature fatigue life of specimens while avoiding a large number of experiments. The results showed that experimental and prediction results were in a good agreement.

Abstract: In this paper, the sandwich structure which is consist by the aluminum foam core and CBF(continuous basalt fiber) composite plate is tested by the static and dynamic mechanical property under confining pressure, and the confining pressure experiment is done through add cylindrical tube to the sandwich structure circular specimens. The static mechanical property is tested by WDW3100 electronic universal testing machine, and its dynamic mechanical property is tested by the SHPB(Spilt Hopkinson Press Bar) device, Besides, the strain rate effect of this sandwich structure under confining pressure is tested too, From the experiment results we can see the static and dynamic mechanical properties of confining and no confining results is very different, and this study will provide references for further numerical simulation and damage studying of this kind of sandwich structure.

Abstract: The CBF (continuous basalt fiber) composite as new and high mechanical property material have been widely applied in actual engineering. The composite material may inevitably occur all kinds of defects during fabrication and using, so in this paper, the AE (acoustic emission) and ESSPI (electronic shearography speckle pattern interferometry) technique are adopt to study the defects or damage of the CBF composite plate. The AE technique is adopted to detect the damage phenomenon of the CBF composit plate specimen tension experiment, and the ESSPI technique is adopt to study the defects of the CBF composite plate which its defects are made by artificial. From the experiment results it can be see that these techniques can detect the position and damage of the CBF composite plate, and these study can provide useful reference for the application of the CBF composite.