GREEN FUNCTION ON TWO-PHASE SATURATED MEDIUM BY CONCENTRATED FORCE IN TWO-DIMENSIONAL DISPLACEMENT FIELD

The Green function on two-phase saturated medium by concentrated force has a broad and important use In seismology, seismic engineering, soil mechanics, geophysics, dynamic foundation theory and so on. According to the Green function on two-phase saturated medium by concentrated force in three-dimentional displacement field obtained by Ding Bo-yang et al., it gives out the Green function in two-dimensional displacement field by infinite integral method along x(3)-direction derived by De Hoop and Manolis. The method adopted in the thesis is simpler. The result will be simplified to the boundary element method of dynamic problem.

AN ANALYSIS OF THE LARGE DEFLECTION OF AN ELASTIC-PLASTIC CANTILEVER SUBJECTED TO AN INCLINED CONCENTRATED FORCE

Based on the Plastica theory (see ref. [12]), the large deflection of an elastic-perfectly plastic cantilever subjected to an inclined concentrated force at its tip, before the unloading in the plastic region occurs, is analyzed in this paper. The emphasis of the analysis is put on the effects of the angle of inclination of the concentrated force upon the deformed shape, the load-deflection relationship and the length of the plastic region. Both analytical and computed results are given.

Large deflection of circular membrane under concentrated force

The analytical solution to a Foppl-Hencky membrane with a rigidly clamped boundary condition under concentrated force is provided. Stability of a nonlinear circular membrane is investigated.

SINGULARITY UNDER A CONCENTRATED FORCE IN ELASTICITY

We first discuss singularity problem of a sort of partial differential equation involving d funetion. Using this result we then have the answer to various singularity problems in elasticity due to the presentation of a concentrated force. Lastly corresponding conclusions in vibration problem are drawn.

PLANE ELASTIC PROBLEM ON RIGID LINES ALONG CIRCULAR INCLUSION

The plane elastic problem of circular-arc rigid line inclusions is considered. The model is subjected to remote general loads and concentrated force which is applied at an arbitrary point inside either the matrix or the circular inclusion. Based on complex variable method, the general solutions of the problem were derived. The closed form expressions of the sectionally holomorphic complex potentials and the stress fields were derived for the case of the interface with a single rigid line. The exact expressions of the singular stress fields at the rigid line tips were calculated which show that they possess a pronounced oscillatory character similar to that for the corresponding crack problem under plane loads. The influence of the rigid line geometry, loading conditions and material mismatch on the stress singularity coefficients is evaluated and discussed for the case of remote uniform load.

AN EXPLICIT TENSOR EXPRESSION FOR THE FUNDAMENTAL SOLUTIONS OF A BIMATERIAL SPACE PROBLEM

In this paper, by using the method of tensor operation, the fundamental solutions, given in the references listed, for a concentrated force in a three-dimensional biphase-infinite solid were expressed in the tensor form, which enables them to be directly applied to the boundary integral equation and the boundary element method for solving elastic mechanics problems of the bimaterial space. The fundamental solutions for Mindlin's problem, Lorentz's problem and homogeneous space problem are involved in the present results.

Experimental investigation on impact performances of GLARE laminates

An experimental investigation was carried out on the damage resistance to a concen- trated quasi-static indentation force and low-velocity impact of four kinds of glass-reinforced aluminum laminates （GLARE for short）. Compared with the experimental results of the CFRP （Carbon Fiber Reinforced Plastics） laminates, the performance of GLARE was determined. By means of concentrated quasi-static indentation force test, typical force displacement response, the maximum contact force and dent depth were received, Through drop-weight low-velocity impact tests, impact force histories, indentation depths （through a new method） and dissipated energy were obtained. The test results show that the force-displacement response of GLARE 4 laminates under the concentrated quasi-static indentation force has an obvious fiat roof and the failure is instantaneous, which are different from CFRP laminates. The indention will be visible once the impact happens. C-scan results find that there is no delamination besides the impact area after both the concentrated quasi-static indentation and low-velocity impact. The dissipated energy approximately equals the impact energy.

Influence of carrier concentration on the resistive switching characteristics of a ZnO-based memristor

Sandwich-style memristor devices were synthesized by electrochemical deposition with a ZnO film serving as the active layer between Al-doped ZnO （AZO） and Au electrodes. The carrier concentration of the ZnO films is controlled by adding HNO3 during the growth process. A resulting increase in carrier concentration from 10^17 to 10^19 cm^-3 was observed, along with a corresponding drop in the on--off ratio from 6,437% to 100%. The resistive switching characteristics completely disappeared when the carrier concentration was above 1029 cm-3, making it unsuitable for a memory device. The decreasing switching ratio is attributed to a reduction in the driving force for oxygen vacancy drift. Systematic analysis of the migration of oxygen vacancies is presented, including the concentration gradient and electrical potential gradient. Such oxygen vacancy migration dynamics provide insight into the mechanisms of the oxygen vacancy drift and provide valuable information for industrial production of memristor devices.