Chongqing University of Technology

About: Chongqing University of Technology is a education organization based out in Chongqing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 5199 authors who have published 4205 publications receiving 35954 citations. The organization is also known as: Chongqing Institute of Technology.

A systematic approach for multi-objective lightweight and stiffness optimization of a car body

Abstract: Optimization for the car body under the condition of guaranteeing vehicle overall mechanical performance remains a key automotive engineering design challenge currently. The present study first attempts to group the car body components into safety components (SCs) and non-safety components (NSCs) based on their correlation with crashworthiness safety and then focuses on the potential of NSCs, which compromise a group of thin-walled plate parts that basically have little impact on overall vehicle crashworthiness, for multi-objective lightweight and stiffness optimization. To be more specific, the finite element (FE) models of significant vehicle performance, including the static-dynamic stiffness of the car body and the frontal and side crashworthiness of the vehicle, were first separately established and validated against experimental outcomes. On this basis, SCs closely related to vehicle crashworthiness safety, including frontal safety components (FSCs) and side safety components (SSCs), were figured out through crashworthiness analyses. As a result, the initial NSCs (INSCs) were also determined by filtering out all the SCs from the car body. Subsequently, sensitivity analysis (SA) was employed to screen the INSCs for the final NSCs (FNSCs) for multi-objective lightweight and stiffness optimization, considering minimizing the total mass while maximizing both the static global torsional stiffness and the dynamic first-order torsional frequency of the car body as three optimization objectives. Radial basis function (RBF), multi-objective particle swam optimization (MOPSO) algorithm and modified grey relational analysis (MGRA) were then separately utilized for constructing meta-models, solving optimization process, and identifying the best trade-off design. In addition, different optimization strategies were compared. According to the optimized outcomes, the car body is dramatically lightweight optimized by 7.92 kg; meanwhile, the static-dynamic stiffness of the car body is slightly improved and the overall vehicle crashworthiness is basically guaranteed. Hence, the proposed systematic approach gains insight on reasonable and efficient multi-objective optimization for the car body.

Coupling coordination and obstacle factors between tourism and the ecological environment in Chongqing, China: a multi-model comparison

Abstract: This paper constructed the tourism and eco-environment index system, calculated the coupling and coordination relationship between them in Chongqing, from 2000 to 2017, by comparing 9 combination m...

Numerical Simulation of Violent Impinging Jet Flows with Improved SPH Method

Abstract: This paper presents an implementation of an improved smoothed particle hydrodynamics (SPH) method for simulating violent water impinging jet flow problems. The presented SPH method involves three major modifications on the traditional SPH method, (1) The kernel gradient correction (KGC) and density correction are used to improve the computational accuracy and obtain smoothed pressure field, (2) a coupled dynamic solid boundary treatment (SBT) is used to remove the numerical oscillation near the solid boundary and ensure no penetration condition, (3) a free surface condition, which is obtained from the summation of kernel function and volume, is used to describe the water jet accurately. Different cases about violent impinging jet flows are simulated. The influences of impact velocity and angles are investigated. It is demonstrated that the presented SPH method has very good performance with accurate impinging jet patterns and pressure field distribution. It is also found that the pressure time histories of observation points are greatly influenced by the rarefaction wave from surrounding air. Closer distance from free surface can lead to quicker decay of the pressure time history.