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A spacer grid assembly is one of the main structural components of the nuclear fuel assembly for a Pressurized light Water Reactor (PWR). The spacer grid assembly supports and aligns the fuel rods, guides the fuel assemblies past each other during a handling and, if needed, sustains lateral seismic loads. The ability of a spacer grid assembly to resist these lateral loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired from tests. In this study, a finite element analysis on the dynamic crush strength of spacer grid assembly specimens is carried out. Comparisons show that the analysis results are in good agreement with the test results to within about a 30 % difference range. Therefore, we could predict the crush strength of a spacer grid assembly in advance, before performing a dynamic crush test. And also a parametric study on the crush strength of a spacer grid assembly is carried out by adjusting the weld penetration depth for a sub-sized spacer grid, which also shows a good agreement between the test and analysis results.

A numerical optimization system for sheet metal forming process has been developed based on a combination of response-surface-based optimization strategy with finite element simulation. The most important feature of the optimization system is introduction of a new fracture criterion to predict fracture limit under non-proportional deformation. In addition, a sheet-edge fracture criterion is also introduced to predict fracture limit under stretch-flanging deformation. The numerical optimization system is developed using the fracture criteria as accurate fracture constraints to avoid sheet breakage. The developed optimization system is applied to the optimum blank design for a square-cup deep drawing process of perforated blank. The optimum blank design, which minimizes the amount of material and avoids the sheet fracture, is obtained successfully. The effect of definition of fracture constraints on optimization calculation is also discussed.

Owing to the superior mechanical performance, corrugated steel webs are extensively applied and their shear performance is critical, because of the thin wall. After the steel is corroded and the web is weakened, the problem of shear resistance may become more prominent. The shear performance of corrugated steel webs with local uniform loss was studied to simulate a common corrosion state. Twenty-eight FE models with different defect characteristics, containing defect height and web thickness, are established to simulate corroded corrugated webs. Shear capacity, shear strength, out-of-plane stiffness and bending stiffness are studied. Based on previous studies, the prediction formula is proposed to predict the residual shear strength. Additional FE models are built to validate the reliability. Results indicate that web thickness is the key factor to decide the deformation shape and shear capacity, compared with defect height. Bending stiffness decreases as defect increases. With 62.5% of the initial thickness, the influence of the variation of defect height on the bending stiffness is within 10%. Variation in thickness also affects the sensitivity of shear capacity to corrosion parameters and failure modes. When the thickness exceeds 1.25 mm, about 62.5% of the initial thickness, shear capacity is more sensitive to corrosion height than when the thickness is less than 1.25 mm. The proposed formula is validated and has a good agreement with the FE results, which could help to design the durability of corrugated steel webs and evaluate the performance of existing corrugated steel webs.

In this study, finite element (FE) analysis of underground structure is carried out, which is subjected to the internal blast loading and the structure is surrounded with soil media. Three different methods to analyze the effect of blast loading on structure, i.e. ConWep, smooth particle hydrodynamics (SPH), and couple Eulerian-Lagrangian (CEL) are used for the simulation of blast loading using ABAQUS/Explicit^®. Concrete damage plasticity (CDP), Mohr–Coulomb, Johnson–Cook (JC) plasticity model, Jones–Wilkins–Lee (JWL) equation of state and ideal gas are utilized for defining behavior of concrete, soil, steel, explosive and air, respectively. FE analysis is performed to compare the behavior of structure under different blast modelling methods. The effect of different explosive weights is considered to see the impact of the blast load on the structure. For parametric analysis, three explosive weights, 3kg, 5kg, and 10kg of TNT (trinitro toluene), and three concrete grades, M30, M35, and M40 are considered to see the stability of the structure. The effect of varied explosive weights and varied concrete grades is compared in terms of stress, pressure, and displacement at critical locations of the structure. The outcome of this shows that the change in explosive weight and concrete grade considerably affects the stability of the structure. As the explosive weight increases, damage to the structure increases, and with the increase in the concrete grade, the blast load resistance capacity of the structure increases. It is observed that buried part of the structure is more resistant to blast load compared to the structure visible above ground.

Unbonded fiber-reinforced elastomeric isolator (U-FREI) is an improved device for seismic mitigation of low-rise buildings. The horizontal force — displacement behavior of U-FREI is nonlinear due to rollover deformation and the horizontal stiffness is a function of both vertical load and horizontal displacement. In this paper, stability of a prototype U-FREI is studied based on the dynamic response utilizing finite element (FE) analysis. Furthermore, the horizontal response of the isolator is also evaluated under the design vertical load and increasing horizontal displacement up to $2.00t_r$$(t_r$ is the total thickness of rubber layers) to observe the rollout instability.

This paper investigates the differences in structural response of lightweight internal structures using finite element (FE) simulation to provide quantitative comparison of the advantages of each type of structure. Various configurations, corresponding to different amounts of weight savings, were studied under distributed pressure loading and bending moment loading conditions. It was found that for configurations with less weight savings, the kagome possesses better performance than the honeycomb structure. However, as the amount of weight savings increases, the trend was observed to be reversed, with the honeycomb structure providing much better performance than the kagome structure. In general, it was shown that the honeycomb structure possesses better performance than the kagome structure under cantilever loading conditions.

A mathematical model of wire rope considering space geometric structure and characteristic of the laying process is proposed with self-rotating ratio. Depending on the position in the stranded rope the wires can be in the form of single, double and triple helices, the vector of which can be obtained. And a program for calculating boundary conditions of a three-dimensional finite element modeling is developed to create data which can be accessed by ANSYS for nonlinear analysis. Additionally, the deformation of once laying and secondary laying acting on the wires of a strand or wire rope is analyzed. The results show better agreement with the previous analytical solutions.

A numerical optimization system for sheet metal forming process has been developed based on a combination of response-surface-based optimization strategy with finite element simulation. The most important feature of the optimization system is introduction of a new fracture criterion to predict fracture limit under non-proportional deformation. In addition, a sheet-edge fracture criterion is also introduced to predict fracture limit under stretch-flanging deformation. The numerical optimization system is developed using the fracture criteria as accurate fracture constraints to avoid sheet breakage. The developed optimization system is applied to the optimum blank design for a square-cup deep drawing process of perforated blank. The optimum blank design, which minimizes the amount of material and avoids the sheet fracture, is obtained successfully. The effect of definition of fracture constraints on optimization calculation is also discussed.