This study deals with the stiffness design of geometrically nonlinear structures using topology optimization. Bi-directional Evolutionary Structures Optimization (BESO) is employed to implement the design process. The geometrically nonlinear behavior of the structures are modeled using a total Lagrangian finite element formulation and the equilibrium is found using a Newton-Raphson iterative scheme. The topology optimization of linear and nonlinear modeling are implemented. The sensitivity of the objective function is found with the adjoint method and the optimization problem is solved using BESO’s update method. Objective function of complementary work is evaluated. A special technique called the continuation method is applied to solve the instability of nonlinear structure optimization. ANSYS APDL is also used to do FEA of optimal topology to verify the effectiveness of geometrically nonlinear modelling. The results show that differences in stiffness of structures optimized using linear and nonlinear modelling is generally small but it can be large in some cases, especially structure highly involving buckling behaviour.

It is very common to stabilize the preset value (Wanted value) of analog signals such as temperature, pressure, weight, flow, speed in automatic control. However, these control objects often have some problems such as overshooting, taking a long time to bring the system to a steady value, and large errors. One of the most used systems to overcome these problems is the PID, which is a preset stabilizing system with a quick function that returns the system to the set value in a short time without overshooting. error is close to zero. However, determining the scale parameters Ki, integral Kp, and differential Kd for the system to work optimally is a problem that needs to be studied. This paper presents how to accurately determine differential, integral, and scale coefficients according to 3D virtual reality model. Used a lot in simulation modeling for training and practical applications.

Measuring environmental protection activities is a matter of great concern over the years. In this study, the indicators for evaluating environmental protection activities in industrial parks was built according to the PDSIR model and based on Vietnam's legal framework, including 18 main subjects and 35 indicators. The environmental performance index of industrial park (EPIIP) was established based on the multi-criteria evaluation method and the analytic hierarchy process method. The results of the study indicated that the VSIP I industrial park reached 68.95 points (relatively good level). Moreover, the results also showed that VSIP I was one of the industrial parks practicing good performance to protect environmental problems.