Auto Body Parts Research Articles

A Population Cooperation based Particle Swarm Optimization algorithm for large-scale multi-objective optimization

There are many multi-objective optimization problems (MOPs) in real life that contain a large number of decision variables, such as auto body parts design, financial investment, engineering design, adversarial textual attack and so on. These problems are known as large-scale multi-objective optimization problems (LSMOPs). Due to the curse of dimensionality, existing multi-objective evolutionary algorithm encounter difficulties in balancing convergence and diversity on LSMOPs. In this paper, a Population Cooperation based Particle Swarm Optimization algorithm (PCPSO) is proposed for tackling LSMOPs. To be specific, PCPSO is a two-stage optimizer with two key components: (1) In the first stage, an inter-population collaboration component named Auxiliary Population Cooperation (APC) is used to improve the convergence speed. (2) In the second stage, an intra-subpopulation collaboration component called SubPopulation Cooperation (SPC) is applied to balance convergence and diversity. Experimental results on benchmark problems with up to 5000 decision variables and 2, 3, 5, 10 objectives demonstrate that the proposed PCPSO achieves better performance than several state-of-the-art large-scale multi-objective evolutionary algorithms (LSMOEAs) on most test problems.

The Optimization of Welding Spots’ Arrangement in A-Pillar Patchwork Blank Hot Stamping

With increasingly severe environmental problems, energy saving and environmental protection have become two important issues to be solved in the automobile industry. Patchwork blank hot-stamping technology can be used to obtain light-weight and high-strength parts and is thus increasingly used in the manufacture of autobody parts. Because the main blank and the patched blank need to be connected through spot welding before forming, the welding spots’ arrangement has a great influence on the formability of the part. In this study, a thermal–mechanical coupling finite element analysis model of A-pillar patchwork blanks was established. With the thickness of the patched blank, the distance between the welding spot and the external contour of the patched blank, and the number of welding spots as optimization variables, together with the maximum thinning rate and the maximum welding spot force as objectives, the influence of welding spot arrangement on forming quality was analyzed, and the welding spots’ arrangement was optimized using a central composite design (CCD), the response surface method (RSM), and the genetic algorithm (GA). The results showed that when the initial welding spot was located close to the contour of the patched blank, the bending moment was greater when the weld spot passed through the die corner, leading to the rupture of the welding spot or its surrounding base material due to the greater thinning rate. When the patched blank was thicker than the main blank, the main blank cracked during the forming process due to a greater increase in the thinning rate. The optimal solution of the weld spot arrangement on the A-pillar patchwork blanks was a 1.2 mm thick main blank, 0.8 mm thick patched blank, a distance of 29 mm between the weld spot and the contour line of the patched blank, and 16 weld spots. Hot-stamping experiments were conducted using the optimized weld spots’ arrangement, and high-quality parts were obtained.

Establishment of Mathematical Model of Different Burr Removal Methods for Automobile Valve Body Parts

In the process of auto body parts processing, machining surface at the junction will produce burrs or flares. The existence of burr will have a bad effect on the machining accuracy, assembly accuracy and appearance quality of parts. In industrial production, the cost of removing these burrs is enormous. In automotive parts, the cost of deburring body parts can account for machining costs15% - 20%. Industry practice has shown that the actual cost of deburring systems increases as the complexity and accuracy of parts increase. Precision parts such as automobile valve body require high precision, and burr is usually removed by grinding. In grinding process, different types of burr will adopt different grinding process to purify, frequent adjustment process will affect the production efficiency, so the combination with the characteristics of grinding, the grinding grain edge radius, equivalent negative rake Angle and other factors into consideration, burr types can be divided into three categories, respectively on the three types of burr mathematical modeling, The removal mechanism of different kinds of burr is explained theoretically, which lays a theoretical foundation for improving efficiency in production practice.

Design, Simulation and Experimental Evaluation of Hot-Stamped 22MnB5 Steel Autobody Part

The combination of complex geometry and martensitic microstructure, characterized by ultrahigh strength and hardness, can be obtained in a single hot stamping process. However, this technology requires a multifaceted approach, allowing for an effective and efficient design process that will ensure the elements with the desired properties and shape are produced because of the high tool cost. This paper presents a comprehensive case study of the design process, simulation and experimental evaluation of the hot forming of an automotive door beam. The U-shaped beam designed with CAD was analyzed using the finite element method in the Autoform v.10 software. The modeling process included: a shape definition of the flat blank; a FEM analysis and design of the die, punches, and clamps; and a forming and quenching simulation. The results covered visualization of the forming and quenching stages for different variables including a forming limit diagram; a distribution of the drawpiece thinning; and a diagram showing the hardness of the drawpiece and its microstructure. Based on the results, a full-size tool for hot stamping was first modeled in the CAD and next manufactured. The tool was used to produce an initial sample series that was used to investigate the conditions for continuous use of the tool. One of the produced hot-stamped products was investigated for its hardness and microstructure, which exhibited a beneficial and fully martensitic microstructure with high hardness of above 400 HV1.

Influence of pre-straining and heating on strain-rate sensitivity of AA5182-O

The manufacturing process of auto-body parts usually includes forming (i.e., pre-straining) and baking (i.e., heating), which could alter mechanical properties of the substrate materials. The present study clarifies the influence of pre-straining and heating on the strain-rate dependent mechanical performance of aluminum alloy 5182-O (AA5182-O). Quasi-static and intermediate strain-rate tensile tests were conducted with either AA5182-O material as received or processed by different combinations of pre-straining and heating. The quasi-static test results show that the yield strength is enhanced by pre-straining and weakened by heating, while the ultimate strength is less affected. The test results at different strain-rates show a transition of negative to positive strain-rate sensitivity (SRS) at a critical rate below 100 s−1, and it is revealed that pre-straining enhances the negative effect and heating mainly enhances the positive effect. A modified Khan-Liu model that incorporates the non-monotonic SRS is employed to characterize the influence of pre-straining and heating, and electron backscatter diffraction (EBSD) analysis is performed to address the mechanism behind the SRS variation.

A Mathematical Model of Infrared Heating of Auto Body Parts during Restoration by a Polymer Material

The results of theoretical studies on the power balance of infrared radiation during heating of type II auto body parts is provided. A mathematical model of heating of auto body parts coated by a polymer during infrared processing has been simulated, and comparative calculation and experimental data on temperature and time of infrared heating of bearing shields of electric motors are presented. The consistency of the mathematical model has been demonstrated. The error in determining the temperature and heating time did not exceed 5%.

Modeling of Phase Transformation Kinetics in Resistance Spot Welding and Investigation of Effect of Post Weld Heat Treatment on Weld Microstructure

In recent years, the usage of dual phase (DP) steels, transformation induced plasticity (TRIP) steels and boron steels in some auto body parts has become a necessity because of their strength and lightweight. Resistance spot welding (RSW) being a process were steel is heated and cooled in a very short period of time, the resulting weld nugget is generally fully martensitic, especially in the case of DP, TRIP and boron steels but that also holds for plain carbon steels as AISI 1010 grade which is extensively used in auto body inner parts. Martensite in is turn must be avoided as much as possible when welding steel because it is the principal source of brittleness. Thus, this work aims in finding a mean to reduce martensite fraction and increase phase diversity in weld nugget. The prediction of phase transformation during RSW has been done. Simulations have been performed for 2 mm AISI 1010 sheets and results show that the application of post weld heat treatment leads to the reduction of martensite fraction, and formation of ferrite and bainite in the nugget. Welding experiments have been done in parallel and experimental weld nugget geometry is in good agreement with simulation results.

A New Two-Stage Approach for a Bi-Objective Facility Layout Problem Considering Input/ Output Points Under Fuzzy Environment

Facility layout problem is one of the most important problems in a huge range of industries and services organizations. Simultaneous study of some qualitative and quantitative parameters like closeness relationship between facilities, physical constraints such as input/output points and how to arrange facilities can play a key role to determine the facility layout. Considering these parameters can lead to reduce production costs, increase production capacity, and remove additional displacements. A two-stage approach is proposed to achieve these goals. In the first stage, a goal programming model is proposed to determine weights of the attributes based on the experts' opinions with different preference representation structures. Afterwards, the closeness ratings of the facilities are calculated using weights of attributes. In the second stage, an efficient layout is designed by determining facilities placement sequence, location of the next facility adjacent to the previous one, location of input/output points, and rectilinear feasible shortest path between facilities. Two meta-heuristic algorithms including particle swarm optimization and genetic algorithm are designed due to computational complexity. The objective function is to minimize the sum of products distance between facilities and closeness rating and also to minimize the dead space. A case study of an Auto Body Parts company is demonstrated to verify the efficiency of the proposed two-stage approach. Furthermore, in order to assess the performance of the proposed approach, a comparison is drawn between the proposed approach and five existing approaches in the literature to solve different problems by using the two meta-heuristic algorithms.

Minimizing assembly variation in selective assembly for auto-body parts based on IGAOT

PurposeDimensional quality of sheet metal assemblies is an important factor for the final product. However, the part tolerance is not easily controlled because of the spring back deformation during the stamping process. Selective assembly is a means to decrease assembly tolerance of the assembly from low-precision components. Therefore, the purpose of this paper is to propose a fully efficient method of selective assembly optimization based on an improved genetic algorithm for optimization toolbox (IGAOT) in MATLAB.Design/methodology/approachThe method of influence coefficient is first applied to calculate the assembly variation of sheet metal components since the traditional rigid assembly variation model cannot be used due to welding deformation. Afterwards, the IGAOT is proposed to generate optimal selective groups, which consists of advantages of genetic algorithm for optimization toolbox (GAOT) and simulated annealing.FindingsThe cases of two simple planes and the tail lamp bracket assembly are used to illustrate the flowchart of optimizing combinations of selective groups. These cases prove that the proposed IGAOT has better precision than that of GAOT with the same parameters for selective assembly.Originality/valueThe research objective of this paper is to evaluate the changes from rigid bodies to sheet metal parts which are very complex for selective assembly. The method of IGAOT was proposed to the selected groups which has better precision than that of current optimization algorithms.

Fabrication and testing of Fibre-reinforced Glass-epoxy composite with Seashell as a filler Material

In this study mechanical properties of a Polymer Matrix Composite i.e. mixing E-glass fibre (synthetic fibre) with seashell as filler material and using Lapox L-12 as the epoxy resin with K-6 hardener are tested. The constituents used in this composite are cheaper when compared to other composites and it showcases properties like higher strength, higher stiffness, chemically resistant, good insulation to electricity and light weight too. Three components are fabricated with ratio of sea shell powder varying from 5% to 15% in a total amount of 70:30 (Volume Fraction) fibre to resin ratio. Properties of different ratios of the composite material are determined using various tests like Tensile strength, Three-point bending & Natural frequency is found by FFT analyser. As this composite is light weight and durable, it is can be used in helmets, karts, and auto body parts.

Multi-objective optimization based on improved non-dominated sorting genetic algorithm II for tolerance allocation of auto-body parts

The auto-body is usually composed of compliant sheet metals. The assembly variation is inevitable in the process of auto-body assembly. A reasonable tolerance allocation method for compliant sheet ...

Theoretical and experimental investigation of deep drawing of tailor-welded IF steel blanks with non-uniform blank holder forces

Tailor-welded blank is one of the promising technologies in the application of lightweight materials for auto body parts manufacturing. The material discontinuity across the weld line results in an inhomogeneous deformation and weld line displacement. In this study, a two-dimensional analytical model is proposed to predict the tension distribution along the cross section. An energy method is used to calculate the restraining force due to bending, sliding, and unbending phenomena on the die and punch radii. To control the weld line movement, a blank holder force control strategy is proposed to achieve force equilibrium at the bottom of the part across the weld line. Finite element simulations are performed to study the effect of die and punch radii, friction coefficient, thickness ratio, and blank holder forces on the weld line displacement in strip drawing process. Under a uniform blank holder force, the weld line moves toward the thicker/stronger side implying a higher blank holder force is required for the thinner/weaker side. The results show that the weld line displacement can be controlled by an appropriate blank holder force adjustment. In order to control the weld line movement in square cup deep drawing, blank holder force on the thinner side is increased and its influences on the deformation process are investigated. Comparisons of material draw-in, weld line movement, and forming force show a good agreement between the theoretical, numerical, and experimental results.

Suppression of selective surface oxidation in DP steels by effective shielding of copper — Kinetic simulation and experimental validation

Abstract The high strength steels have become essential for the auto body parts owing to the combination of high strength as well as better crash resistance. The galvanizing and galvannealing of these high strength steels are required for longer performance life of the steels. The constituent alloying elements in the high strength steel e.g. manganese, silicon and chromium have a tendency to oxidize at the steel surface during the continuous annealing of the steel. The oxides greatly inhibit the wettability of steel with molten zinc during galvanizing. In the present study the application of prior copper coating on Dual Phase (DP) steel was shown to act as a diffusion barrier for the alloying elements during annealing. The kinetic simulation for diffusion of manganese and oxygen through the copper layer having an initial thickness of 200 nm showed that the oxidation front can be arrested at the sub-surface region near the steel–copper interface. The simulation results were verified with experimental annealing simulation and subsequent depth profiling by Glow Discharge Optical Emission Spectroscopy (GDOES) and Transmission Electron Microscopy (TEM)/Energy Dispersive Spectroscopy (EDS) line scanning. The copper coating was able to suppress the surface segregation and selective oxidation of manganese as oppose to the conventional DP steels. The galvanizing of the copper coated DP steels exhibited defect free zinc coating as compared to the regular DP steels having high number of bare spots. The simulation technique can be further extended to determine the thickness and type of pre-coating layers for high strength steels.

A Multi-agent Approach to Computational Optimization of Metal Forming Processes

In the paper we present a new original approach to a complex multi-phase process optimization problem that relies on dividing the optimization task into partial tasks related to the implementation of individual phases. To implement this concept, we propose a multi-agent approach. Its practical realization is shown on the example of manufacturing process for auto body parts made of the Advanced High Strength Steels (AHSS). Although it is a rather simple process consisting of only two phases, we assumed, however, that the results obtained will allow to extend further research to more complex problems. We present the operating principles of a multi-agent model, the flow of the messages between agents, and the architecture of the system. To ensure the proper speed of the whole system a simple and flexible multi-agent framework called Eve was used to develop a prototype of the system. Research performed, as well as preliminary tests have shown that a multi-agent approach can be successfully applied to reduce complexity of the whole optimization processes. Due to splitting a single, complex optimization process into several, partially independent optimization processes, delegating them to autonomous agents, and application of a knowledge-based reasoning system, significant advantage could be observed over to the solutions described so far in the literature.

Impact of inter-sheet gaps on laser overlap welding performance for galvanised steel

For overlap joints with different galvanised sheet combinations, the inter-sheet gap size and range control under different conditions were experimentally studied, and the factors affecting the inter-sheet gap range were examined. The application of a δ control method to laser welding of car door parts was explored. The results indicate that the formation and strength of weld joints initially improve and then worsen as the inter-sheet gap increases. The inter-sheet gap for different types of sheet combinations has a specific range, the value of which is related to the sheet thickness, weld pool width, welding speed, and laser beam parameters. Further, the consistency of the size of δ along the entire welding bead can be maintained by using a subsection welding method. Application of the conditions identified here, in combination with optimal technological parameters, can facilitate the high-quality welding of auto-body parts.

Sheet Moulding Compounds of Large Auto Body Parts Made from Polymeric Composite

The paper presents the parameter influence on the process of pressing aids in reinforced thermosetting polymer mold blanks Sheet Moulding Compound type (SMC) used to obtain large pieces of automotive bodywork. In the first part of the paper presents complex recipe constitutive factors of R-SMC prepreg, analyzing and choosing the optimal tehnnology of each component type, depends on the application blank piece and specific technical and economic parameters. Further the paper presents the influence of compression parameters (time, pressure, temperature) on the pressing process and optimize the parameters for each blank so that the reproducibility of the mass production process of obtaining large parts of Figures Size automotive to be insured. Finally it presents a model highlighting induced reorientation of fibers in the manufacture of SMC's as if prepregs of R-SMC, there is a dependency between the SMC belt speed production and planar orientation of the fibers in the direction of forward her.

Fixture layout optimisation based on a non-domination sorting social radiation algorithm for auto-body parts

Auto-body compliant parts are easily deformed during clamping and welding, and fixture layout is very important to the final product quality. However, it is very difficult to design fixture layout because it needs to synchronously satisfy the requirements of assembly tolerance and gravity deformation, which are calculated by finite element analysis. This paper proposes a new method to optimise fixture scheme by a non-domination sorting social radiation algorithm (NSSRA). Firstly, unfeasible nodes are eliminated by four rules according to manufacturing experiences. Afterwards, a few groups are divided based on positions of all feasible nodes. N groups are optimised using NSSRA. Finally, the best fixture layout is generated by selecting the feasible points among the optimal groups in last step. A case study of inner hood is used to illustrate the proposed method, and the results suggest that NSSRA has better efficiency and higher accuracy than NSGA-II.

An analytical approach to predict web-warping and longitudinal strain in flexible roll formed sections of variable width

To reduce weight and improve passenger safety there is an increased need in the automotive industry to use Ultra High Strength Steel (UHSS) for structural and crash components. However, the application of UHSS is restricted by their limited formability and the difficulty of forming them in conventional stamping. An alternative method of manufacturing structural auto body parts from UHSS is the flexible roll forming process, which allows the manufacture of metal sheet with high strength and limited ductility into complex and weight-optimized components. One major problem in the flexible roll forming of UHSS is the web-warping defect, which is the deviation in height of the web area over the length of the profile. It has been shown that web-warping is strongly dependant to the permanent longitudinal strain formed in the flange of the part. Flexible roll forming is a continuous process with many roll stands, which makes numerical analysis extremely time intensive and computationally expensive. An analytical model of web-warping is therefore critical to improve design efficiency during the early process design stage before FEA is applied. This paper establishes for the first time an analytical model for the prediction of web-warping for the flexible roll forming of a section with variable width. The model is based on evaluating longitudinal edge strain in the flange of the part. This information is then used in combination with a simple geometrical model to investigate the relationship between web-warping and longitudinal strain with respect to process parameters.

A new assembly variation analysis model based on the method of power balance for auto-body parts

Purpose – The purpose of this paper is to propose a new assembly variation analysis model to analyze assembly variation for sheet metal parts. The main focus is to analyze assembly processes based on the method of power balance. Design/methodology/approach – Starting with issues in assembly variation analysis, the review shows the critical aspects of tolerance analysis. The method of influence coefficient (MIC) cannot accurately analyze the relationship between part variations and assembly variations, as the welding point is not a point but a small area. Therefore, new sensitivity matrices are generated based on the method of power balance. Findings – Here two cases illustrate the processes of assembly variation analysis, and the results indicate that new method has higher accuracy than the MIC. Research limitations/implications – This study is limited to assembly variation analysis for sheet metal parts, which can be used in auto-body and airplane body. Originality/value – This paper provides a new assembly variation analysis based on the method of power balance.

Study on Torsion-Eliminating Performance of Laterally Interconnected Air Suspension

Laterally interconnected air suspension combines the right and left air springs with pneumatic pipes, which can protect the auto-body parts from fatigue damage and increase the service life of vehicles. The mathematical model of full vehicle with laterally interconnected air suspension was established based on the analysis of its working principle, and a test bench was built. The simulation and experimental results show that, laterally interconnected air suspension can reduce the peak of dynamic body torsion load effectively, especially for steady state conditions, in which the body torsion load caused by the spring force can be nearly eliminated.