Highly Differentiated Target Detection under Extremely Low-Light Conditions Based on Improved YOLOX Model

This paper expounds upon a novel target detection methodology distinguished by its elevated discriminatory efficacy,specifically tailored for environments characterized by markedly low luminance levels.Conventional methodologies struggle with the challenges posed by luminosity fluctuations,especially in settings characterized by diminished radiance,further exacerbated by the utilization of suboptimal imaging instrumentation.The envisioned approach mandates a departure from the conventional YOLOX model,which exhibits inadequacies in mitigating these challenges.To enhance the efficacy of this approach in low-light conditions,the dehazing algorithm undergoes refinement,effecting a discerning regulation of the transmission rate at the pixel level,reducing it to values below 0.5,thereby resulting in an augmentation of image contrast.Subsequently,the coiflet wavelet transform is employed to discern and isolate high-discriminatory attributes by dismantling low-frequency image attributes and extracting high-frequency attributes across divergent axes.The utilization of CycleGAN serves to elevate the features of low-light imagery across an array of stylistic variances.Advanced computational methodologies are then employed to amalgamate and conflate intricate attributes originating from images characterized by distinct stylistic orientations,thereby augmenting the model’s erudition potential.Empirical validation conducted on the PASCAL VOC and MS COCO 2017 datasets substantiates pronounced advancements.The refined low-light enhancement algorithm yields a discernible 5.9%augmentation in the target detection evaluation index when compared to the original imagery.Mean Average Precision(mAP)undergoes enhancements of 9.45%and 0.052%in low-light visual renditions relative to conventional YOLOX outcomes.The envisaged approach presents a myriad of advantages over prevailing benchmark methodologies in the realm of target detection within environments marked by an acute scarcity of luminosity.

Research status and progress of hot stamping

In this article,current application,materials,key equipments,finite element(FE) simulation and parts properties of hot stamping are introduced.The investigations of all processes and further excellent processes are described.The survey of existing works,especially key equipments has revealed several gaps.Some new ideas and programs are proposed on the basis of traditional process.This article aims at providing an insight into a whole process backgrounds and pointing out the great potential for further investigations and innovations of hot stamping.

Application of CAE technology for Geely car lightweight

In order to reduce energy consumption and protect the human survival environment,the lightweight has became the development trend of the world automobile industry.On the premise of ensuring the strength,safety and driving performance of the car,the major car enterprises try to reduce the curb weight of the car,fuel consumption and emissions.Not only a lot of new technologies and new products have been generated,but also joint vehicle development process and computer aided engineering(CAE) analysis technology have been developed.Since the entry into the "Automobile Lightweight Technology Innovation Strategic Alliance" in Dec.2007,Geely Group has been focusing on lightw eight construction of vehicle and key assemblies in every stage of the vehicle product development.Among vehicles appeared on the market and in research,it has presented continuously better performance.The paper describes application examples and successful experience of CAE simulation analysis and performance optimization during the lightweight design and development of a self-developed model of Geely,and looks forward to the prospects for the development of lightweight of Geely vehicle.

Comparative analysis by simulating and testing pole impact for hot stamping front crossbeam of automobile

Hot stamping 22MnB5 steel plate with ultra-high strength has been widely used for body structural members in consideration of automobile safety and lightweight.This paper presents a verification program of simulating and testing pole impact in order to verify if the front crossbeam reinforcement assembly can meet the design requirements,reduce the overall vehicle simulation and test cost and shorten the operation period.In the same condition,the simulation proved conforming to the design requirements;however,the bumper cracked at the impacting point in the course of pole impact test.The analysis of the crack by optical microscope,Vickers and scanning electron microscope indicates that mixture of ferrite,bainite and martensite was produced in the weld heat-affected zone of the 340/590DP tow hook holder and the 22MnB5 front crossbeam;therefore,their hardness and mechanical property were reduced obviously,so that they fractured when impacted.No welding process with continuous weld but spot welding or other bonding method may be employed for the reason that the capacity of the 22MnB5 steel plate in the weld heat-affected zone was reduced obviously.

Research on plastic fender development and key technologies

Automotive lightweight and safety performance come into play as key technologies to promote competiveness, and average applied amount of automotive plastics has become a significant sign for automotive industrial development level of a country.Various performances of a vehicle with plastic automotive fenders are analyzed in the paper.The research is emphasized on sinking-resistance and pedestrian protection performance of the plastic fenders by studying plastics characteristics and simulation analysis.It offers references for engineering design in which both automotive lightweight and safety performance are achieved and well balanced.

A study on light-aging resistance of instrument panel materials and bumper materials on the automobile

The light-aging test method commonly used in the automotive industry is utilized to carry out light- aging research on automotive instrument panel （IP） materials and bumper materials. On one hand, the impacts of common light-aging test methods on aging degree of automotive component materials are reviewed; on the other hand, the light-aging resistances of different component materials are compared. The results show that, for light-aging behavior of IP materials, the aging degree of the third test method is not severer than that of the second method, but it is severer than that of the first method. The light-aging resistance of IP material A is al- most the same as that of IP material B. With reference to light-aging behavior of bumper materials, the aging de- gree of three common test methods indicates that the aging degree of the sixth test method is not severer than that of the fourth method, but it is severer than that of the fifth method. The light-aging resistance of bumper material D is superior to that of bumper material C.

Research on application of plastic materials in cars

This paper gives analysis of application status and prospect of plastic materials from the aspects of applied material amount comparison,development of new materials & new technologies,lightweight,design conception of new components,recyclability,simplification and diversity of materials,standardization of material specification and presents corresponding conclusions and suggestions.

Carbody Structural Lightweighting Based on Implicit Parameterized Model

Most of recent research on carbody lightweighting has focused on substitute material and new processing technologies rather than structures. However, new materials and processing techniques inevitably lead to higher costs. Also, material substitution and processing lightweighting have to be realized through body structural profiles and locations. In the huge conventional workload of lightweight optimization, model modifications involve heavy manual work, and it always leads to a large number of iteration calculations. As a new technique in carbody lightweighting, the implicit parameterization is used to optimize the carbody structure to improve the materials utilization rate in this paper. The implicit parameterized structural modeling enables the use of automatic modification and rapid multidisciplinary design optimization （MDO） in carbody structure, which is impossible in the traditional structure finite element method （FEM） without parameterization. The structural SFE parameterized model is built in accordance with the car structural FE model in concept development stage, and it is validated by some structural performance data. The validated SFE structural parameterized model can be used to generate rapidly and automatically FE model and evaluate different design variables group in the integrated MDO loop. The lightweighting result of body-in-white （BIW） after the optimization rounds reveals that the implicit parameterized model makes automatic MDO feasible and can significantly improve the computational efficiency of carbody structural lightweighting. This paper proposes the integrated method of implicit parameterized model and MDO, which has the obvious practical advantage and industrial significance in the carbody structural lightweighting design.

Deformation mechanism and forming properties of 6061Al alloys during compression in semi-solid state

The 6061 semi-solid aluminium alloy feedstocks prepared by near-liquidus casting were compressed in semi-solid state by means of Gleeble-3500 thermal-mechanical simulator.The relationship between the true stress and the true strain at different temperatures and strain rates was studied with the deformation degree of 70%.The microstructures during the deformation process were characterized.The deformation mechanism and thixo-forming properties of the semi-solid alloys were analyzed.The results show that the homogeneous and non-dendrite microstructures of semi-solid 6061Al alloy manufactured by near-liquidus casting technology could be transformed into semi-solid state with the microstructure suitable for thixo-forming which are composed of near-spherical grains and liquid phase with eutectic composition through reheating process.The deformation temperature and strain rate affect the peak stress significantly rather than steady flow stress.The resistance to deformation in semi-solid state decreases with the increase of the deformation temperature and decrease of the strain rate.At steady thixotropic deformation stage, the thixotropic property is uniform, and the main deformation mechanism is the rotating or sliding between the solid particles and the plastic deformation of the solid particles.

Numerical simulation of hot stamping of side impact beam

Ls-DYNA software is adopted to conduct research of numerical simulation on hot stamping of side impact beam to calculate the temperature field distribution,stress field distribution,forming limit diagram(FLD) figure,etc.in the course of hot stamping so as to predict and analyze the formability of parts.ProCAST software is employed to conduct research of numerical simulation on solid quenching course concerning hot stamping to calculate temperature field distribution of tools and component of multiple stamping cycles.The results obtained from numerical simulation can provide significant reference value to hot stamping part design,formability predication and tools cooling system design.

Electrochemical behavior and underpotential deposition of Sm on reactive electrodes(Al,Ni,Cu and Zn)in a LiCl-KCl melt

Sm extraction from a LiCl-KCl melt was carried out by forming alloys on various electrodes,including Al,Ni,Cu,and liquid Zn,and the electrochemical behaviors of the resultant metal products were investigated using different electrochemical techniques.While Sm metal deposition via the conventional two-step reaction process was not noted on the inert electrode,underpotential deposition was observed on the reactive electrodes because of the latter's depolarization effect.The depolarization effects of the reactive electrodes on Sm showed the order Zn>Al>Ni>Cu.Sm-M(M=Al,Ni,Cu,Zn)alloys were deposited by galvanostatic and potentiostatic electrolysis.The products were fully characterized by X-ray diffractometry(XRD)and scanning electron microscopy(SEM)-energy dispersive spectrometry(EDS),and the stability of the obtained M-rich compounds was determined.Finally,the relationship between the electrode potential and type of Sm-M intermetallic compounds formed was assessed on the basis of the observed electrochemical properties and electrodeposits.

Optimized body structure and packaging for car ODB impact performance

Front bumper,crash box and side rail are key body structural parts in front crash.Deformation space is affected by compartment packaging.The improvement suggestions are proposed to solve the problems existed in the current vehicle structure and compartment packaging based on the areas that influence performance of automobile offset deformable barrier impact, such as the side rail,mounting,storage battery packaging,etc.It is proved that 40%offset crash simulation result of one certain car is well-correlated with the physical test.Optimization cases meet the crash performance requirements.The objective of the analysis is to guide structural design and improves a car’s crash safety performance.

The test device for heat friction coefficient of high strength steel

Using high strength steel and ultra-high strength steel in hot stamping and automobile parts is one of the most important ways of the automobile lightweight,which is the development trend of automobiles currently.In this paper, the development of test device for heat friction coefficient by high strength steel can provide important technical parameters for hot stamping process,making the right selection of equipment types,mold design,technology optimization,and research and development of lubrication medium of press forming.At the same time,the experiments indicate that the instrument has not only accurate test result but also good repeatability.

Multidimensional CAE methods for car body structure optimization

The computer aided engineering(CAE) analysis technique has become one of the most important means in modern automobile development due to its remarkably computing capability.With the development of CAE bussiness software and intensive research on automotive development process,the CAE technique,which was only used as an auxiliary validation tool in the later product development in the past,is gradually used in each stage of product development now.Furthermore,accurate and fast analysis data can be supplied effectively.Especially in current CAE application, based on some optimization technologies such as sensitivity,feature and topology,the parametric design gradually enables a CAE engineer to be free from the condition which a convention analysis usually lags behind a design,and makes it be parallel to or even anterior to the design.Under the circumstance,the CAE resources can be maximized in each project development department,thereby promoting the project progress and quality,and creating a new philosophy of 'analysis-driven design'.

Study of front bumper process on the basis of hot stamping

The fitting method is used for obtaining the constitutive relation of ultra-high strength steel in this paper.At the same time,the forming limit of material is researched under different deformation conditions.Through experiments,the paper obtains stress-strain curve under different deformation temperatures and strain rates.On the basis of experimental data,the constitutive relation model is established which can reflect the deformation capacity of ultra-high strength steel during process of hot stamping.Combining with finite element simulation results of hot stamping by the commercial software AUTOFORM,transfer path of load and matching law of strength,the paper determines the design criteria and forming process requirements of parts manufactured by hot stamping.Through setting different process parameters,such as punch velocity and friction coefficient,and blank shape,the paper finds that process parameters and blank shape have an essential effect on the quality of parts.

Performance improvement of car body structure in 100% frontal impact

During the 100%front impact,all the parts of front car will participate in the course;the crash stiffness of bodywork will also reach the peak.During the crash,rational structure of bodywork can resist the distortion,absorb more energy and get better mode of distortion and low deceleration rate,so as to meet the performance of crash safety.The paper mainly makes optimization analysis based on the problems of front side rails,subframe,firewall,and optimization cases are confirmed which can decrease the intrusion and deceleration rate of the whole car.The structure of bodywork after optimization can meet the performance of crash safety.

Simulation about hot stamping of ultra-high strength steel on the basis of lightweight technology

With the development of automobile lightweight,it is very necessary to apply the ultra-high strength steel parts manufactured by hot stamping,which offers the possibility to reduce the weight of automobiles and maintain the safety requirement.In order to complete hot stamping,it is important to design the structure of parts reasonably,which is related with reasonable matching of strength.The objective of this paper is to guide the design of parts manufactured by hot stamping and find the forming technical requirements of vehicle performance.Through experiments,the paper obtains the stress and strain curves at different deformation temperatures and strain rates.Based on experimental data, the constitutive relationship model is established which can reflect the deformation capacity of ultra-high strength steel during the process of hot stamping.Combined with finite element simulation results of hot stamping by commercial software AUTOFORM,transfer path of load and matching law of strength,the paper determines the design criteria and forming technical requirements of parts manufactured by hot stamping.At the same time,the impact performance of front cross member internal plate is taken into consideration.

Lightweight design of automotive front crossbeam assembly

This paper reviews the development course of the front crossbeam assembly for a self-owned brand vehicle model based on lightweight and passive safety performance.Combining with an A00 model variant,the paper details the design of extruded aluminum-alloy front crossbeam assembly from the perspectives of optimal design,performance verification, lightweight effect and cost control.The following results in the technical and engineering applications have been achieved.The weight of the developed aluminum-alloy crossbeam can be reduced by 51%.The simulated analysis of the collision rigid wall,the 40%offset hammering as well as the static crush test of energy-absorbing box show that alter reasonable materials matching and size optimization of the crossbeam and the energy-absorbing boxes,the level of crash safety can be improved.The price of aluminum-alloy front crossbeam can be lowered by using the extruding die instead of the stamping die to reduce the die cost-sharing.

Study of engaged performance regulation in controlled transfer clutch of 4WD car based on genetic sliding mode control

This paper investigates an approach to improve the engagement quality of controlled transfer clutch mode in 4 wheel drive(WD) car from three considerations of reducing friction,smoothening responsiveness and alleviating jerk.The method utilizes an improved sliding mode control with genetic algorithm instead of simplified mode to determine appropriate values of parameters in control close- loop.The simulation results show that the method is effective for improving the engagement quality of coupling satisfying different design needs for 4WD car,as well as robustness even if input torque is changed at a certain range.

Numerical study of effect of post injection coupled with EGR on combustion and emission performances of CRDI engine fueled with biodiesel-ethanol blends

Energy shortage and environmental pollution are becoming more serious,biodiesel is regarded as the most promising alternative fuel for diesel engines due to its environmentally friendly and renewable characteristics.In this study,the biodiesel-ethanol blends were used in a diesel engine,and the purpose of the study was to simultaneously control the NOx and soot emissions of the diesel engine by adjusting the injection strategy and EGR rate.A turbocharged,six-cylinder,common rail direct injection(CRDI)engine model was established using GT-Power.The effects of the main-post injection strategy and post injection coupled with exhaust gas recirculation(EGR)on combustion and emission characteristics were investigated at a maximum torque speed and a medium load.The results show that when the main-post injection strategy is employed,the combustion duration of the main injection is shortened with an increase in the main-post injection interval(MPI).When the MPI increased to more than 18℃A,the heat release of post injection could be observed clearly from the curve of the heat release rate,NOx emissions decreased by 5.70%and 7.12%,respectively,and soot emissions decreased by 25.56%and 30.20%,respectively.Moreover,with the increasing post injection quantity,the combustion duration of the main injection shortened,and the peak heat release rate(PHRR)of the post injection increased.When the fuel quantity for the post injection increased from 2 to 6 mg,NOx emissions decreased from 2.33%to 9.80%,and soot emissions decreased from 16.10%to 34.97%.The effect of post injection quantity on emissions was more significant than that of the MPI.In addition,with increasing EGR rate,the ignition delay is prolonged,the peak cylinder pressure,PHRR,peak combustion temperature and NOx emissions decrease,whereas soot emissions increase gradually.Main-post injection can improve the NO-soot trade-off,the optimal EGR rate is 22.86%under a post injection quantity of 4 mg and a MPI of 22℃A.