To obtain the material true constitutive relation of tensile specimens after necking, we proposed an experimental-numerical combined method (ENM) based on the simple tension test results and finite element analysis (FEA). An iterative scheme was used to minimize the errors between the simulated and experimental load-displacement curves by modifying the imported stress-strain data step by step, and the true stress was determined when the error was less than a given infinitesimal value. In addition, we developed a special program to implement this algorithm automatically and save operating time. As a verification, the true stress-strain curves obtained by the traditional analytical method (TAM) and ENM were compared and employed to analyze the large deformation behavior of both cylindrical and rectangular specimens. The results showed that ENM was applicable for both specimens and could achieve an adequate description of the mechanical response of the materials after necking formation more effectively.

Aiming at the complexity and uncertainty of rock and soil body, the paper proposed a tunnel surrounding rock parameters identification method combining numerical simulation, particle swarm optimization and artificial neural network. The method acquired data set between rock soil parameters and monitoring displacement and trained artificial neural network. The analytical theory and method are introduced in detail, analyzes the tunnel of Dalian Metro by the proposed method, and gets satisfied results. Which states that the parameters identification method based on PSO-ANN is feasible and has good foreground.

Aiming at the complexity and uncertainty of rock and soil body, the paper the paper introducing a new global intelligent optimization arithmetic – Difference Evolution (DE) and combined with stress return mapping nonlinear elastic-plastic Finite Element Method(FEM), realizing rapid elastic plastic parameters identification of surrounding rock. The analytical theory and method are introduced in detail, analyzes the tunnel of Dalian Metro by the proposed method, and gets satisfied results.

A lightweight vehicle front seat with a sandwich structure, which consists of skin layers made of glass fibre-reinforced thermoplastic prepregs and a core consisting of a warp knitted spacer fabric filled with polyurethane foam, was developed. The strength test simulations of the seat structure were performed using a Finite Element Analysis approach. The results validate the new sandwich design of the vehicle seat with its adequate strength under a static load. With the innovative lightweight design, the mass of the seat was reduced up to 57 % in comparison to the reference seat from conventional mass production. In addition, a manufacturing process was advised for a large-scale production of the lightweight design within one workstation.

Bridge engineering concrete’s Freeze-thaw damage is the main durability diseases which take place in the service process of north China. Aiming at the Songhuajiang Highway Bridge being located in the cold-warm alternant area, According to this environmental characteristics, a batch of concrete samples were made in the construction site by using Material and ratio of the Bridge’s practical construction, they were shipped back to the laboratory and then were used in freeze-thaw test and carbonization test under the influence of freeze-thaw. Obtained the dynamic elastic modulus and compressive strength variation regulation according to the freeze-thaw circles of the concrete specimens. Analyzed the relation between laboratory experiment and field atmospheric exposure test, the paper constructs the durability degradation appraising model and predicts the maintenance-free life of Songhuajiang Highway Bridge. It has important meaning for the maintenance and repair measures in the process of this bridge.