Multi-Scale Design and Optimization of Composite Material Structure for Heavy-Duty Truck Protection Device

In this paper,to present a lightweight-developed front underrun protection device(FUPD)for heavy-duty trucks,plain weave carbon fiber reinforced plastic(CFRP)is used instead of the original high-strength steel.First,the mechanical and structural properties of plain carbon fiber composite anti-collision beams are comparatively analyzed from a multi-scale perspective.For studying the design capability of carbon fiber composite materials,we investigate the effects of TC-33 carbon fiber diameter(D),fiber yarn width(W)and height(H),and fiber yarn density(N)on the front underrun protective beam of carbon fiber compositematerials.Based on the investigation,a material-structure matching strategy suitable for the front underrun protective beam of heavy-duty trucks is proposed.Next,the composite material structure is optimized by applying size optimization and stack sequence optimization methods to obtain the higher performance carbon fiber composite front underrun protection beam of commercial vehicles.The results show that the fiber yarn height(H)has the greatest influence on the protective beam,and theH1matching scheme for the front underrun protective beamwith a carbon fiber composite structure exhibits superior performance.The proposed method achieves a weight reduction of 55.21% while still meeting regulatory requirements,which demonstrates its remarkable weight reduction effect.

A Shifting Strategy for Electric Commercial Vehicles Considering Mass and Gradient Estimation

The extended Kalman filter (EKF) algorithm and acceleration sensor measurements were used to identify vehiclemass and road gradient in the work. Four different states of fixed mass, variable mass, fixed slope and variableslope were set to simulate real-time working conditions, respectively. A comprehensive electric commercial vehicleshifting strategy was formulated according to the identification results. The co-simulation results showed that,compared with the recursive least square (RLS) algorithm, the proposed algorithm could identify the real-timevehicle mass and road gradient quickly and accurately. The comprehensive shifting strategy formulated had thefollowing advantages, e.g., avoiding frequent shifting of vehicles up the hill, making full use ofmotor braking downthe hill, and improving the overall performance of vehicles.

Fluid-Structure Coupled Analysis of the Transient Thermal Stress in an Exhaust Manifold

The development of thermal stress in the exhaust manifold of a gasoline engine is considered.The problem is addresses in the frame of a combined approach wherefluid and structure are coupled using the GT-POWER and STAR-CCM+software.First,the external characteristic curve of the engine is compared with a one-dimen-sional simulation model,then the parameters of the model are modified until the curve matches the available experimental values.GT-POWER is then used to transfer the inlet boundary data under transient conditions to STAR-CCM+in real-time.The temperature profiles of the inner and outer walls of the exhaust manifold are obtained in this way,together with the thermal stress and thermal deformation of the exhaust manifold itself.Using this information,the original model is improved through the addition of connections.Moreover,the local branch pipes are optimized,leading to significant improvements in terms of thermal stress and thermal deforma-tion of the exhaust manifold(a 7%reduction in the maximum thermal stress).

PERIOMARTHRITIS TREATED WITH PAIN POINT PRESSURE IN COMBINATION WITH LOCAL EXERCISES

Periomarthritis is a traumatic ordegenerative lesion of the shoulder joint andadjacent tissues, characterized by shoulderpain which is worse during the night, andlimitation of abduction, intorsion andextorsion of the shoulder joint. The age ofonset is usually around 50 years, though

Effect of Adding Extruded Mg-Mischmetal Intermediate Alloy on Microstructure and Properties of Die-Casting Magnesium Alloy AZ91D

The preparation techniques of Mg-mischmetal intermediate alloy and the effects of the mischmetal addition ranging from 0.45% to 1.04% on the microstructure and properties of AZ91D alloy prepared by die casting were investigated. The Mg-MM intermediate alloy was prepared by permanent mold casting and then was extruded into the bars. The microstructure and analytical studies were carried out using optical microscopy and differential scanning calorimetry (DSC). Testing results shows the Mg-MM intermediate alloy could melt easily down at die casting temperature of 680 ℃ that was lower than the melting point of lanthanum (918 ℃) and that of cerium (798 ℃). This was propitious to protection the alloy from the oxidation at high temperatures. Then magnesium alloy test bars were produced under conventional cold chamber die casting condition with addition of different weight of the Mg-MM intermediate alloy. Observation and analysis indicated that the microstructures of the alloy were refined and RE containing Al phase was formed with increasing RE addition. The data obtained by tensile tests showed that alloying with mischmetal improved the tensile property of the AZ91D magnesium die casting alloy at ambient temperature.

The status,challenges,and trends:an interpretation of technology roadmap of intelligent and connected vehicles in China(2020)

Purpose–The rapid development of Intelligent and Connected Vehicles(ICVs)has boomed a new round of global technological and industrial revolution in recent decades.The Technology Roadmap of Intelligent and Connected Vehicles(2020)comprehensively analyzes the technical architecture,research status and future trends of ICVs.The methodology that supports the roadmap should get studied.Design/methodology/approach–This paper interprets the roadmap from the aspects of strategic significance,technical content and characteristics of the roadmap,and evaluates the impact of the roadmap on researchers,industries and international strategies.Findings–The technical architecture of ICVs as the“three rows and two columns”structure is studied,the methodology that supported the roadmap is explained with a case study and the influence of key technologies with proposed development routes is analyzed.Originality/value–This paper could help researchers understand both thoughts and methodologies behind the technology roadmap of ICVs.

Observation on Therapeutic Effect in Acupuncture Treatment of Soft Tissue Injuries by Differentiation of Deficient and Excessive Patterns

目的:比较虚实辨证针刺法与常规循经刺法治疗软组织损伤的疗效差异。方法:将380例软组织损伤患者随机分为辨证组(200例,虚实辨证刺法)与循经组(180例,循经取穴刺法),观察比较两组疗效。结果:辨证组的痊愈率为86%,循经组为31.11%,差异有非常显著性意义(P<0.01);从痊愈好转病例的总平均治疗时间比较,辨证组为8.8 d,循经组为15.6 d,差异有非常显著性意义(P<0.01),辨证组明显优于循经组。结论:治疗软组织损伤,虚实辨证针刺法优于常规循经刺法。

Obstacle Avoidance in Multi-Agent Formation Process Based on Deep Reinforcement Learning

To solve the problems of difficult control law design,poor portability,and poor stability of traditional multi-agent formation obstacle avoidance algorithms,a multi-agent formation obstacle avoidance method based on deep reinforcement learning(DRL)is proposed.This method combines the perception ability of convolutional neural networks(CNNs)with the decision-making ability of reinforcement learning in a general form and realizes direct output control from the visual perception input of the environment to the action through an end-to-end learning method.The multi-agent system(MAS)model of the follow-leader formation method was designed with the wheelbarrow as the control object.An improved deep Q netwrok(DQN)algorithm(we improved its discount factor and learning efficiency and designed a reward value function that considers the distance relationship between the agent and the obstacle and the coordination factor between the multi-agents)was designed to achieve obstacle avoidance and collision avoidance in the process of multi-agent formation into the desired formation.The simulation results show that the proposed method achieves the expected goal of multi-agent formation obstacle avoidance and has stronger portability compared with the traditional algorithm.