3D quasi-transient thermo-mechanical analysis for vehicle brake disc

Biao Hu,Xingyan Zhang,Yang Liu,Junjie Yan,Xiaobing Liu,Xin Wang,Richard Sun 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.2

An alternative numerical method is developed to predict the thermo-mechanical behavior of brake disc during braking. Steady-state aerodynamic simulation for entire vehicle with variant speeds are conducted to analyze the convective heat transfer characteristic of the disc surface. Then the transient heat transfer boundary of the disc is obtained by interpolating the steady-state simulation results. Based on that, the transient thermo-mechanical coupled simulation for brake disc is performed via finite element method. With those work, the characteristics of transient temperature field and stress field of the brake disc are analyzed. Meanwhile, the characteristic of contact pressure distribution on friction interface is also obtained. The results show that during the braking process, for any node in the friction areas of the brake disc surface, its temperature rise curve fluctuates like a sawtooth. The temperature field has a significant effect on the stress field of the brake disc, both in distribution and variation. To verify the numerical method and validate the simulation results, a full-scale vehicle brake-thermalperformance test is carried out. By comparison, the simulation results show good agreement with the experimental results. The proposed numerical method enables an efficient and economical way to predict and evaluate the thermo-mechanical behavior of the brake disc in early phase of vehicle development.

Study on Thermodynamic Behavior, Microstructure and Mechanical Properties of Thin-Walled Parts by Selective Laser Melting

Biao Hu,Gaoshen Cai,Jinlian Deng,Kai Peng,Bingxu Wang 대한금속·재료학회 2024 METALS AND MATERIALS International Vol.30 No.1

To investigate the thermodynamic behavior of thin-walled parts fabricated by selective laser melting, an indirect sequentiallycoupled thermal–mechanical numerical modeling was developed. The three-dimensional Gaussian attenuation bodyheat source model and thermophysical parameters varying with temperature were considered. To validate the numericalmodel, the thin-walled part was manufactured by selective laser melting, and the experiment results were compared with thesimulation results. It is found that the variation trend of residual stress in simulation and experiment is in good agreement. Moreover, The microstructure and mechanical properties of the thin-walled parts were analyzed. The simulation resultsshow that the thermal conductivity and the heat accumulation have a critical influence on the evolution of the molten pooland cooling rate. The thermal stress along the laser scanning direction is larger than the other two directions, and the highstressarea is mainly distributed in the middle position of the part and the joint of the part and the substrate. Besides that, theX-component of stress of the top layer gradually decreases as the deposition layer increases. The experiment results showthat the microstructure of thin-walled parts is mainly composed of acicular martensite under the action of complex thermalcycle. The fracture mode of thin-walled parts show a typical quasi-brittle fracture.

Numerical investigation of heat transfer characteristics for Subsea Xmas tree assembly

Biao Hu,Hongwu Zhu,Kuang Ding,Fangling Xu,Youjiang Zhang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.11

This study focuses on the heat transfer characteristic of a horizontal subsea Xmas tree assembly at a high spatial resolution. Computationalfluid dynamics (steady Reynolds-averaged Navier-Stokes) in combination with Low Reynolds number modelling (LRNM) isadopted for heat transfer analysis, which has been validated against a full scale underwater gate valve heat transfer experiment with goodagreements. The characteristics of cold sea water flowing through the subsea tree, and of convection heat transfer between the subsea treeand ambient cold water are obtained. The typical “hot spots,” which have high Convection heat transfer coefficient (CHTC) and creategreat large amounts of heat loss, are numerically determined. Under the designed water depth, the effects of installation orientation, seawater velocity, and inner oil temperature on convection heat transfer are investigated as well. Such work is significant for thermal designof the subsea tree to increase structural reliability and flow assurance level.

CONVERGENCE PROPERTIES OF A CORRELATIVE POLAK-RIBIERE CONJUGATE GRADIENT METHOD

Hu, Guofang,Qu, Biao 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1

In this paper, an algorithm with a new Armijo-type line search is proposed that ensure global convergence of a correlative Polak-Ribiere conjugate method for the unconstrained minimization of non-convex differentiable function.

The Impact of Greenhouse Vegetable Farming Duration and Soil Types on Phytoavailability of Heavy Metals and Their Health Risk in Eastern China

Biao Huang,Lanqin Yang,Wenyou Hu 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

REGENERATIVE BRAKING CONTROL STRATEGY OF ELECTRIC VEHICLES BASED ON BRAKING STABILITY REQUIREMENTS

Jiang Biao,Zhang Xiangwen,Wang Yangxiong,Hu Wenchao 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.2

Electric vehicles are effective way to solve energy and environmental problems, but the promotion and application of electric vehicles are suppressed by their limited endurance range seriously. The regenerative braking technology is an important method to increase the endurance range of the electric vehicle. During the braking process, the kinetic energy of the electric vehicle can be converted into electric energy and stored in the energy source device with the regenerative braking system, so the endurance range of the electric vehicle can be increased accordingly. In order to increase the efficiency of energy recovery, a regenerative braking strategy with the optimization distribution algorithm is proposed in this paper, and the braking forces of the front and rear axles are distributed optimally with variable ratios based on the braking strength. With the optimal braking force distribution ratio and related constraint conditions, the regenerative braking control strategy was designed to meet the braking stability and the maximum braking energy recovery. And then a simulation model of the braking control strategy was built with MATLAB/Simulink software, and the simulation tests on UDDS and NEDC cycle conditions were done to verify the effectiveness of the designed regenerative braking control strategy. Compared with the control strategy of ADVISOR software, the braking energy recovery efficiency was improved more than 51.9 % while maintaining the braking stability.

Elastic local buckling behaviour of corroded cold-formed steel columns

Nie Biao,Xu Shanhua,Hu WeiCheng,Chen HuaPeng,Li AnBang,Zhang ZongXing 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.48 No.1

Under the long-term effect of corrosive environment, many cold-formed steel (CFS) structures have serious corrosion problems. Corrosion leads to the change of surface morphology and the loss of section thickness, which results in the change of instability mode and failure mechanism of CFS structure. This paper mainly investigates the elastic local buckling behavior of corroded CFS columns. The surface morphology scanning test was carried out for eight CFS columns accelerated corrosion by the outdoor periodic spray test. The thin shell finite element (FE) eigen-buckling analysis was also carried out to reveal the influence of corrosion surface characteristics, corrosion depth, corrosion location and corrosion area on the elastic local buckling behaviour of the plates with four simply supported edges. The accuracy of the proposed formulas for calculating the elastic local buckling stress of the corroded plates and columns was assessed through extensive parameter studies. The results indicated that for the plates considering corrosion surface characteristics, the maximum deformation area of local buckling was located at the plates with the minimum average section area. For the plates with localized corrosion, the main buckling shape of the plates changed from one half-wave to two half-wave with the increase in corrosion area length. The elastic local buckling stress decreased gradually with the increase in corrosion area width and length. In addition, the elastic local buckling stress decreased slowly when corrosion area thickness was relatively large, and then tends to accelerate with the reduction in corrosion area thickness. The distance from the corrosion area to the transverse and longitudinal centerline of the plate had little effect on the elastic local buckling stress. Finally, the calculation formula of the elastic local buckling stress of the corroded plates and CFS columns was proposed.

Convergence Properties of a Correlative Polak-Ribiacuteere Conjugate Gradient Method

Guofang Hu,Biao Qu 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.22 No.1-2

In this paper, an algorithm with a new Armijo-type line search is proposed that ensure global convergence of a correlative Polak-Ribi´ere conjugate method for the unconstrained minimization of non-convex differentiable function.

Three-dimensional unsteady cavitating flows around an axisymmetric body with a blunt headform

Changli Hu,Guoyu Wang,Guanghao Chen,Biao Huang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.3

We investigated the three-dimensional characteristics in the unsteady cavitating flow over an axisymmetric body with a blunt headform. A high-speed video camera was used to visualize the cavitating flow structures. A modified PANS (Partially-averaged Navier-Stokes) turbulence model coupled with Kubota cavitation model was used to simulate the time-evolution process of the unsteady cavitatingflows. The finite-time Lyapunov exponent (FTLE) and Lagrangian coherent structures (LCS) methods are applied to investigate thethree-dimensional flow patterns. The results show that the numerical method is capable of simulating the unsteady cavitating flow forcapturing the attached cavity with maximum-length, the cavity break-off and U-type shedding, in accordance with the qualitative featuresobserved in the experiment. Three-dimensional characteristics are extremely impressive in the unsteady cavitating flows. The re-entrantflows originate from different circumferential positions at the closure region of the attached cavity, and move upstream at differentspeeds. Moreover, substantial circumferential motions in the unsteady cavitating flow are found based on Lagrangian trajectories, and itis reasonably deduced that the U-type shedding cavity is primarily induced by the effect of re-entrant flow motions consisting of movingupstream and circumferential flows as well.

Improved SVR Method for Predicting the Cutting Force of a TBM Cutter Using Linear Cutting Machine Test Data

Mengmeng Hu,Biao Li,Bo Zhang,Ruirui Wang,Lei Chen 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.11

This research introduces a support vector regression (SVR) method to predict the cutting forces acting on the constant cross section (CCS) disc cutter, including the normal force (FN) and rolling force (FR), based on linear cutting machine (LCM) test data. To improve the prediction effect, an improved SVR-Outlier Detection (SVR-OD) method and an Additional Input Variable (AIV) method are proposed. After removing the outliers, 148 typical LCM test samples form the training set. Here, 70 samples from the Hangzhou No.2 Water Supply Channel constitute the test set. The prediction results show that the Root-mean-squared Relative Error (RMRE) values of the normal force and rolling force are 19.5% and 24.8%, respectively, and the corresponding determination coefficients are 0.845 and 0.807, respectively. For the prediction of the peak cutting force with an important reference to tunnel boring machine (TBM) design, the proportions of samples with an Absolute Relative Error (ARE) value of less than 20% for FN and FR are 9/10 and 7/7, respectively. The above prediction results are better than those of the common SVR method; thus, the developed method can effectively simulate the cutting force required by a rock mass with good integrity. The cutting force prediction using LCM test data is feasible and practical. In addition, the comparison of the prediction results between the improved SVR and common SVR methods shows that the improved SVR-OD and AIV methods play an active role in improving the prediction accuracy of the SVR method.