We conducted a field test on Huitougou (HTG) Tunnel, which is a typical shallow-buried and unsymmetrically loaded tunnel. The on-site monitoring data indicated that the surrounding rock pressure and lining stress on both sides of the tunnel were indeed asymmetrical and that the pressure ratios (original unsymmetrical coefficient) of each corresponding monitoring point were different. According to the tunnel design principle, we proposed the unsymmetrical coefficient (UC) to characterize the asymmetrical degree of the tunnel, and verified and compared the UC of the field test and numerical simulation results. The effects of different factors on the UC such as the slope angle of the ground, the thickness of the overburden cover, the physical and mechanical properties of the surrounding rock, and the construction method were studied and analyzed. The research results reveal that the bias coefficient calculated by the numerical simulation was close to the monitoring results. The results of the factor analysis indicate that the slope angle, overburden thickness, and elastic modulus significantly affected the bias degree, while other factors had little effect. The concise and clear UC accurately described the unsymmetrical degree of any unsymmetrical-loaded tunnel and provided more accurate judgment regarding the safety of the tunnel design phase and construction phase.

On application of BDI STS-WIFI testing system and Dasylab software, the testing process for strain of the casing tube with the packer rubber being seated is carried out. From the process the different friction force and normal pressure of specified seating pressure are achieved, by which the empirical formula is matched. Setting the experimental result as the boundary condition, the calculation result of the practical location of the five-stage packer on basis of oil and gas wells rod string mechanics is obtained, the maximum deviation of which is 0.1m compared with the magnetic location data. The research process on the experiment method proves its accuracy in laboratory while promoting the precision of the block location of the multistage packer in practical well casing tube.

The dynamic characteristics of a steel/CFRP (carbon fiber reinforced plastic) drive shaft were studied. finite element analysis (FEA) and an experiment were carried out to investigate the natural frequencies and mode shapes. The results of the experiment verified the effectiveness of the finite element model. At the same time, the FEA was used to predict the dynamic characteristics of the shaft for different stacking sequences, fiber orientation angles, and layer thicknesses. The results show that the natural frequency increases with decreasing fiber orientation angles. And the positive and negative stacking sequences are helpful to improve natural frequency. The layer thicknesses and stacking sequences will have a pronounced effect in a specific size of the shaft.

Because reinforced-fiber has characteristic of single step forming in three-dimensional braided composites, analysis of mechanical performance is very different from laminates. This paper proceeds from the micro-structure of 3-D braided composites, some review and research are presented detailedly, and the several model’s merit and demerit are analyzed, which can conduct dynamicists to choose reasonable numerical model. The mechanical performance can be predicted accurately, and the next research can be guided using above analysis.

Based on ANSYS, a finite elements method study is conducted on couple fields of fixed tube-sheet heat exchanger. On the basis on the calculating results, the paper tries to analyze and evaluate the reliability and parameter sensitivity of the couple field of fixed tube-sheet heat exchanger, so as to present references for the reliable design on the intensity of mechanical equipments.