浅谈高中物理实验的复习

为了加强实验教学，应对学生的实验能力进行考核，明确怎样才能复习好一个物理实验．

Numerical verification of similar Cam-clay model based on generalized potential theory

From the mathematical principles, the generalized potential theory can be employed to create constitutive model of geomaterial directly. The similar Cam-clay model, which is created based on the generalized potential theory, has less assumptions,clearer mathematical basis, and better computational accuracy. Theoretically, it is more scientific than the traditional Cam-clay models. The particle flow code PFC3 D was used to make numerical tests to verify the rationality and practicality of the similar Cam-clay model. The verification process was as follows: 1) creating the soil sample for numerical test in PFC3 D, and then simulating the conventional triaxial compression test, isotropic compression test, and isotropic unloading test by PFC3D; 2)determining the parameters of the similar Cam-clay model from the results of above tests; 3) predicting the sample's behavior in triaxial tests under different stress paths by the similar Cam-clay model, and comparing the predicting results with predictions by the Cam-clay model and the modified Cam-clay model. The analysis results show that the similar Cam-clay model has relatively high prediction accuracy, as well as good practical value.

An in vitro and finite element study of load redistribution in the midfoot

A good knowledge of midfoot biomechanics is important in understanding the biomechanics of the entire foot,but it has never been investigated thoroughly in the literature.This study carried out in vitro experiments and finite element analysis to investigate the midfoot biomechanics.A foot-ankle finite element model simulating the mid-stance phase of the normal gait was developed and the model validated in in vitro experimental tests.Experiments used seven in vitro samples of fresh human cadavers.The simulation found that the first principal stress peaks of all midfoot bones occurred at the navicular bone and that the tensile force of the spring ligament was greater than that of any other ligament.The experiments showed that the longitudinal strain acting on the medial cuneiform bone was-26.2±10.8μ-strain,and the navicular strain was-240.0±169.1μ-strain along the longitudinal direction and 65.1±25.8μ-strain along the transverse direction.The anatomical position and the spring ligament both result in higher shear stress in the navicular bone.The load from the ankle joint to five branches of the forefoot is redistributed among the cuneiforms and cuboid bones.Further studies on the mechanism of loading redistribution will be helpful in understanding the biomechanics of the entire foot.

Simulation analysis theory and experimental verification of air-cushion isolation control of high concrete dams

To focus on the key scientific problem of process control of dynamic catastrophe of high dams,presented for the first time are the modelling theory of liquid-gas-solid tri-phase coupling of the air-cushion isolation control of high dams and its numerical simulation method,and theoretical description of the complicated dynamics problem of the tri-phase coupling-thermodynamics state-material-contact bi-nonlinearity,as well as the simulation analysis of the key effects of dynamic catastrophe of the air-cushion isolated high dam engineering.The analytic solution of plane-wave with rigid-dam body was created.The simulation comparison of dynamic catastrophe processes of 305 m Jinping arch dam with and without seismic control was carried out,and the results were basically in agreement with that obtained from the large shaking table tests,and verify each other.The entire air-chamber and optimized air-cushion with varying thickness were presented to develop a optimization method.The large shaking table tests of the isolated dam model,which is satisfied with the basic dynamic similarity relations,were performed for the first time.The test data seemed to be convincing and were in agreement with the dynamic simulation results of the tested model,thereby providing an experimental verification to the simulation theory and method.The combination experiments of theoretical model and physical model demonstrated that the hydrodynamic pressure of high arch dams can be reduced by more than 70% as well as the first and third principle stresses of the dam body reduced by more than 20%-30%,thereby the global anti-seismic capacity of the high dam being improved significantly.The results have shown that the air-cushion isolation is the prior developing direction of structural control technology of high concrete dams.