Autobody Components Research Articles

Hall effects and Cattaneo–Christov heat flux on MHD flow of hybrid nanofluid over a varying thickness stretching surface

The study of nanofluids and hybrid nanofluids is gaining conceivable importance due to their characteristics of being so useful in various daily life applications. This study deals with the motion of an electro conductive, incompressible magneto-hydrodynamic (MHD) hybrid nanofluid across a stretched surface of variable thickness. The objective of this study is motivated by a number of manufacturing and machine-building applications. However, no attempt has been made to establish MHD flow of hybrid nanofluid along a stretching sheet (a sheet with variable thickness) while keeping an eye on the impact of Hall current. In real-life situations, variable-thickness sheets are crucial in the creation of flexible containers and, additionally, in the layout and production of aerospace wings and auto body components. This study extends our fundamental knowledge of fluid dynamics and heat transmission in intricate systems. Recognizing how magnetic effects, nanofluid traits and heat conduction interplay can help researchers make valuable developments and breakthroughs in the areas of fluid mechanics and heat transfer. Hall effects are vital for applications including conductive fluids or plasma as they provide a more precise understanding of the movement of charged nanoparticles in the presence of a magnetic field. For hybrid nanofluid, we mixed the nanoparticles of titanium dioxide and copper (TiO2–Cu) into the water. Due to the low noxiousness and chemical strength of titanium dioxide-based nanoparticles, they have great uses in research. We also consider the effects of Cattaneo–Christov heat flux to analyze the heat transfer of nanoparticles and Hall current effects, which make the flow three-dimensional. For both fundamental research and real-world applications, it is of the utmost importance to take into account the Hall effects and Cattaneo–Christov heat flux in the MHD flow analysis of hybrid nanofluid over stretched surface. It makes it possible to describe the phenomenon more precisely and can enhance the effectiveness and efficiency of numerous technical procedures. By using appropriate transformations, the equations that govern the flow are transformed into a system of non-dimensional ordinary differential equations. The non-dimensional system of equations has been solved numerically by using the ND Solve command in Mathematica Software, which is based on a multistep predictor-corrector method. For velocity and temperature profiles, the interplay of numerous developing parameters on flow is depicted graphically. The Hall parameter enhances the axial velocity but reduces the transverse velocity, while the magnetic field has the opposite effects. The temperature increases with the volume fraction of nanoparticles but decreases with the thermal relaxation parameter.

차체 도어의 간격/단차 품질 최적화를 위한 부품 조립 위치 수정 알고리즘 개발

자동차 도어와 차체 사이의 간격과 단차가 너무 크거나 작거나 고르지 않으면 심미성과 기능을 저하시킨다. 그런데 이 간격과 단차를 결정하는 요인은 부품의 품질뿐 아니라 공정 중 발생하는 부품변형, 공정 자체의 편차, 설비의 편차 등 다양하여, 간격과 단차의 품질을 항상 일정하게 관리하는 것이 지극히 어렵다. 따라서 현장에서는 도어의 조립 상태를 모니터링하고 그 결과에 따라 도어가 차체에 조립되는 위치와 자세를 조정하는 방법을 사용한다. 본 연구에서는 이러한 도어 장착 위치의 조정을 논리적이고 체계적으로 하여 도어와 차체 사이의 간격과 단차를 최적으로 유지하는 방법을 제시한다. 본 연구의 방법론을 적용하면 경험에 의존하는 기존 방법에서 탈피하여 보다 체계적으로 간격/단차 품질을 개선함으로써 시간과 비용을 절약하고 품질을 최적화할 수 있을 것으로 기대한다.

The Deformation Properties of High Strength Steel Sheets for Auto-body Components

The automotive industry requires defining restrictive criteria for prediction of technology characteristics as well as safety characteristics at car's collision with another object when auto-body components are produced from sheet metal blanks. The article presents the methodology for specification the material properties effects to overloading of human organism. Overloading depends on the geometry of the components, on the strain-hardening intensity and limit value of auto-body component's shortening that affect the component deformation path. Proposed criteria are analyzed for the following sheet metal blanks: microalloyed steel H220PD, TRIP steel RAK 40/70, duplex stainless steel, austenitic steel DIN 1.4301 and deep-drawing steel DX 54. The forming limit curves were measured by tensile test performed on the notched specimens with different notch radius.

Design and optimisation of assembly technique for auto-body components

The dimensional quality of auto-body relates to the whole external appearance, wind noise, the effect of closing the door and even driving smoothness of vehicles. The assembly dimensional quality can be improved by optimising assembly operations between parts and reasonable allocating tolerances of components. A multi-attribute directed liaison graph is proposed to describe precedence relationships and key control characteristics (KCCs) to eliminate unfeasible assembly sequences. A hybrid particle swarm optimisation and genetic algorithm is presented to optimise assembly operations for selecting the best assembly sequence. Based on the above, tolerances of the optimal KCCs are designed by using NSGA-II algorithm according to assembly tolerances and manufacturing costs. To improve optimisation effectiveness, the initial population uses the orthogonal experimental design and sensitivity coefficients of KCCs to generate chromosomes. Finally, the work applied the method by illustrating the process of assembly sequence optimisation and tolerance allocation, and the results show that this case verified the proposed method.

Application of axiomatic design theory to automotive body assembly in the sustainable manufacturing context

This paper presents an application of an axiomatic design theory-based analytical approach to autobody components assembly in the sustainable manufacturing context. The adjoining edges of autobody and closure steel sheet panels are machined via a computer-controlled laser cutting process. Following the hierarchies of the bill of materials designed in the CATIA V5 environment, the autobody components are assembled manually using the novel τ-stoss technology. The preliminary data obtained from the comparative analysis of the reported LS-DYNA crash simulation of 2 and 3 mm thick τ-stoss technology-based steel front rails shows that a high number of τ-stoss technology-based secondary beams present a preventive material failure at the integration joints. A series of experimental test drives of the τ-stoss technology assembled automobile validated the robustness of the design system and reliability of the τ-stoss technology.

Regulating the surface microtopography of galvanized sheet for auto-body components

The use of new materials in the global auto industry is considered. The prospects for new production technologies based on IF steel with regulated surface microtopography are discussed.

Effect of welding conditions on corrosion behaviour of spot welded coated steel sheets

Steel in the galvannealed condition is preferred over simple galvanised steel for autobody components due to its superior corrosion resistance and relatively easy weldability. However, during resistance seam welding, the area at the weld nugget completely loses its zinc coating due to melting. On the other hand, the zinc coating in the heat affected zone (HAZ) is not totally removed although it is affected by the heat input consequent from the welding process. Although this is potentially a problem, the weld nugget has generally less probability of exposure to the open atmosphere as it is usually enveloped within the HAZ. In the present investigation, a reduction in zinc coating thickness in the HAZ from 9 to 1·5 μm has been observed with increasing resistance weld heat input from 775 to 1310 kJ. This reduction is responsible for increasing the corrosion rate from ∼1 to ∼5 mpy. Therefore, in order to reduce corrosion at the HAZ, the weld heat input has to be restricted.

Mechanism of Zn Vapour Suppressed by Al In Laser Lap Welding of High Strength Zinc Coated Sheet Steel

The basic feasibility of laser fusion welding for prefabrication and assembly of zinc-coated sheet steel auto body components has been demonstrated in a significant number of prior studies. For trouble-free high volume manufacturing, however, one leading key technical concern remains incompletely resolved. In lap or similar weld joint geometries, venting of trapped Zn vapour can seriously disturb the molten weld pool and give rise to gross fusion defects. In this paper, the technical status of the issue has been reviewed, and various experiments were planned to explore Al foil as an interlayer and dual beam laser for suppressing Zn vapour. The results have shown that the welding processing is very sTable when the lap 1+1 mm sheet steel is welded by using Nd-Yag laser at 3KW power and 4m/min travel speed (defined as single beam) with 75μm Al foil as interlayer. However, if first using 2KW power and 4m/min travel speed, secondly using 3KW power and4m/min travel speed (defined as dual beam), only 25 μm Al foil can stabilize welding fusion pool. It is found that Al foil just store the Zn vapour in the single beam method and cannot mix with Zn to form Al-Zn binary alloy, because the laser heating is too fast that Zn has been vaporized before Al was melted. But Al can mix with Zn to form Al-Zn binary alloy in the dual beam method, therefore, the boiling temperature is raised to about 1600°C. So that, in laser lap welding of Zn coated (galvanized) sheet steel, the Al-Zn alloy will be more effective than Al metal for stabilizing welding process.

Experimental and numerical studies on the forming behavior of tailor welded steel sheets in biaxial stretch forming

Stretch forming is an important process in making complex stampings for autobody components. In the present work formability of three different types of tailor welded blanks (TWBs) in biaxial stretch forming modes has been studied by conducting limiting dome height (LDH) tests. The TWBs are laser-welded samples of low carbon and ultra low carbon steel sheets with difference in thickness, grade and surface conditions. In TWBs with difference in thickness, the LDH decreases as the thickness ratio increases and the thickness of the thinner side is also crucial. A high thickness ratio causes two major strain peaks on thinner side and fracture takes place due to strain localization at the peak close to the pole. The weld ductility and the extent of difference in properties are the two crucial parameters for formability in TWBs with difference in properties. In both these TWBs, the fracture takes place perpendicular to the weld line and propagates towards the stronger side. Significant weld line movement occurs towards the thicker/stronger side in biaxial stretch forming. The maximum weld line movement occurs at the pole and it increases with increase in thickness ratio and becomes constant beyond a certain thickness ratio. The peak load required to deform the TWB specimens is less compared to the corresponding parent sheets. In case of TWBs with difference in thickness, as the thickness ratio increases, the peak load reduces due to decreasing punch-blank contact area.

A physical based modeling approach for the dynamic behavior of ultrafine grained structures

This paper discusses some experimental results on the influence of grain refinement on the final mechanical properties of IF and microalloyed steels designed for auto-body components. It shows also some modeling approaches to understanding the dynamic behavior of fine-rained materials. The Zerilli–Armstrong (Z–A) and Khan–Huang–Liang (KHL) models for studied steels were implemented into FEM code in order to simulate the dynamic compression tests with different strain rates.