Spot Weld Layout Optimization With Manufacturing Constraints for Vehicle Structural Performance

Author(s):  
Xueyuan Wu ◽  
Yong Xia ◽  
Qing Zhou ◽  
Wayne Cai ◽  
Robert B. Tilove

Spot weld layout on thin walled vehicle structures is an influencing factor to the structural performance such as NVH, durability and crashworthiness. The weld layout is also subject to manufacturing constraints such as minimum weld pitch, thickness and curvature of flanges, and accessibility of weld gun. Using an S-shaped thin walled tube as an example, this paper presents a study of spot weld layout optimization considering both structural performance and manufacturing constraints for reducing design iterations between the performance design and the manufacturing design. First, several complex manufacturing constraints, including minimum spot weld pitch, maximum curvature of flange, etc., are mathematically characterized. Then, with and without typical manufacturing constraints, the weld layout is optimized respectively for crash performance and torsion performance of the structure. The effects of adding manufacturing constraints on the spot weld layout optimization are evaluated. The analysis results reveal that the crash performance responses are generally less sensitive to the spot weld layout while the torsion stiffness is closely related to the spot weld layout. To analyze why the crash performance is less dependent on the weld layout, a detailed study is further conducted to reveal the relation between the weld layout and the crash performance of S-shaped thin walled tube. It shows that the parameters for assessing the structural crash performance have distinct sensitivity to the spot weld layout design. For instance, the peak impact force is generally sensitive to the spot welds placed in the curved segment and the total energy absorption capacity is mainly determined by the curvature design of the tube instead of the spot weld layout design.

Author(s):  
Qing Zhou ◽  
Xueyuan Wu ◽  
Yong Xia ◽  
Wayne Cai

Spot weld layout is critical to structural performance of vehicle and its design is also subject to manufacturing constraints. In this study, using thin-walled tube crash as an example, we establish the relation between structural performance and weld layout design with manufacturing constraints from resistance spot welding. First, a straight tube crash performance is evaluated as a function of flange width, weld distance to flange corner, and weld pitch, without consideration of manufacturing constraints. All these parameters exhibit certain influence on the deformation mode and the energy absorption capacity. Then, an S-shaped tube is studied in the design optimization of weld layout by adding manufacturing constraints. The proposed approach can determine optimized results by simultaneously considering crash performance and manufacturing constraints. It is also concluded that weld layout has more significant influence on crash performance in straight tubes than in S-shaped tubes.


2014 ◽  
Vol 599 ◽  
pp. 141-144 ◽  
Author(s):  
M. Afrasiab ◽  
G. Faraji ◽  
V. Tavakkoli ◽  
M.M. Mashhadi ◽  
A.R. Bushroa

2019 ◽  
Vol 11 (1) ◽  
pp. 41-68 ◽  
Author(s):  
Chukwuemeke William Isaac

The dynamic oblique crushing of circular thin-walled tubes with the presence of non-propagating crack was investigated numerically. The material considered was strain rate sensitive with crack located at the distal end of the tube. Major crashworthiness parameters were obtained and the analysis of the structural response for idealized and finite element crushed thin-walled tubes was also carried out. The study shows that crack initiation on energy absorbing tubes increase their crushing force efficiency under oblique impact, decrease their crushing force efficiency under axial impact and reduce their crashworthiness performance such as the energy absorption capacity and specific energy absorption under axial and oblique impact. Results of the crashworthiness parameters, deformation modes, damage morphology, stress–strain relations, absorption energy characteristics and crushing force-displacement history were obtained. Furthermore, the numerical study reveals both the desirable and undesirable consequence of crack on the overall crashworthiness performance of energy absorbing circular thin-walled tubes.


Author(s):  
D. Tankara ◽  
R. Moradi ◽  
Y. Y. Tay ◽  
H. M. Lankarani

Over the past few decades, much research work has been conducted on the development of advance crashworthy structures to increase the energy absorption of mechanical systems. Thin-walled tubes are primarily used as structural reinforcements and as energy absorbing components. The high-energy absorption characteristics of cellular foams have attracted great attention to further enhance this superior capability. In particular, nanotechnology has been utilized in the development of advanced cellular materials for the automotive and aerospace industry. The primary objective of this study is to conduct a parametric study using experimental and finite element methods to examine and quantify the performances of thin-walled tube when filled with carbon nano particulates. To accomplish this study, compression tests are carried out to obtain the load-deflection curves of the nano-foams when subjected to different weight percentages of carbon nano fibers. Next, the specific energy absorbed and the collapse mechanism of nano foam filled thin-walled tubes are analyzed and compared with the empty ones. Finally, an illustrative study on the use of nano foams for vehicular applications is presented by using a vehicle bumper numerical model. The carbon nano foam is installed into the cavity of the bumper model and a full-frontal crash simulation is performed. Overall, this study has shown that the energy absorption capacity of thin-walled structures can be significantly enhanced with the use of carbon nano foams.


Alloy Digest ◽  
1994 ◽  
Vol 43 (8) ◽  

Abstract NICROBRAZ 50 is a low-melting, free-flowing filter metal for honeycomb structures and thin-walled tube assemblies. It has low solubility. This datasheet provides information on composition, physical properties, and hardness. It also includes information on corrosion resistance as well as joining. Filing Code: Ni-460. Producer or source: Wall Colmonoy Corporation.


Author(s):  
Farid Triawan ◽  
Geraldy Cahya Denatra ◽  
Djati Wibowo Djamari

The study of a thin-walled column structure has gained much attention due to its potential in many engineering applications, such as the crash box of a car. A thin-walled square column usually exhibits high initial peak force, which may become very dangerous to the driver or passenger. To address this issue, introducing some shape patterns, e.g., origami folding pattern, to the column may become a solution. The present work investigates the compressive properties and behavior of a square box column structure which adopts the Miura origami folding pattern. Several test pieces of single-cell Miura origami column with varying folding angle and layer height are fabricated by a 3D printer. The filament is made of Polylactic Acid (PLA), which is a brittle material. Then, compression tests are carried out to understand its compressive mechanical properties and behavior. The results show that introducing a Miura origami pattern to form a thin-walled square column can dramatically lower down the initial peak stress by 96.82% and, at the same time, increase its ductility, which eventually improves the energy absorption capacity by 61.68% despite the brittle fracture behavior.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1221
Author(s):  
Lu Bai ◽  
Jun Liu ◽  
Ziang Wang ◽  
Shuanggui Zou

In the field of cold bending, it is necessary to use ball mandrels, especially to bend thin-walled tubes with a small radius. However, the bending process with a ball mandrel is complex and expensive, and it is easy to jam the core ball inside the tube. To solve these issues, we designed two kinds of hollow non-ball mandrel schemes with low stiffness that were suitable for the small radius bending of thin-walled tubes. We evaluated the forming quality of cold bending numerically and the influence of the hollow section length and thickness on the forming indices. Our results showed that the thickness of the hollow section has a greater influence on forming quality than the length. As the hollow section’s thickness increased, the wrinkling rate first declined by approximately 40% and then increased by above 50%. When the thickness was 11 mm in scheme 1 and 13 mm in scheme 2, the wrinkling rate reached minimum values of 1.32% and 1.50%, respectively. As the hollow section’s thickness increased, the flattening rate decreased by more than 60% and the thinning rate increased by about 40%. A multi-objective optimization of forming indices was carried out by ideal point method and grey wolf optimizer. By comparing the forming results before and after optimization, the feasibility of using the proposed hollow mandrel was proved, and the hollow mandrel scheme of standard cylinder is therefore recommended.


2021 ◽  
Vol 11 (5) ◽  
pp. 2142
Author(s):  
Trung-Kien Le ◽  
Tuan-Anh Bui

Motorbike shock absorbers made with a closed die employ a tube-forming process that is more sensitive than that of a solid billet, because the tube is usually too thin-walled to conserve material. During tube forming, defects such as folding and cracking occur due to unstable tube forming and abnormal material flow. It is therefore essential to understand the relationship between the appearance of defects and the number of forming steps to optimize technological parameters. Based on both finite element method (FEM) simulations and microstructural observations, we demonstrate the important role of the number and methodology of the forming steps on the material flow, defects, and metal fiber anisotropy of motorbike shock absorbers formed from a thin-walled tube. We find limits of the thickness and height ratios of the tube that must be held in order to avoid defects. Our study provides an important guide to workpiece and processing design that can improve the forming quality of products using tube forming.


2014 ◽  
Vol 1019 ◽  
pp. 96-102
Author(s):  
Ali Taherkhani ◽  
Ali Alavi Nia

In this study, the energy absorption capacity and crush strength of cylindrical thin-walled structures is investigated using nonlinear Finite Elements code LS-DYNA. For the thin-walled structure, Aluminum A6063 is used and its behaviour is modeled using power-law equation. In order to better investigate the performance of tubes, the simulation was also carried out on structures with other types of cross-sections such as triangle, square, rectangle, and hexagonal, and their results, namely, energy absorption, crush strength, peak load, and the displacement at the end of tubes was compared to each other. It was seen that the circular cross-section has the highest energy absorption capacity and crush strength, while they are the lowest for the triangular cross-section. It was concluded that increasing the number of sides increases the energy absorption capacity and the crush strength. On the other hand, by comparing the results between the square and rectangular cross-sections, it can be found out that eliminating the symmetry of the cross-section decreases the energy absorption capacity and the crush strength. The crush behaviour of the structure was also studied by changing the mass and the velocity of the striker, simultaneously while its total kinetic energy is kept constant. It was seen that the energy absorption of the structure is more sensitive to the striker velocity than its mass.


Author(s):  
Weiye Zhang ◽  
Yanchen Li ◽  
Beibei Wang ◽  
Jingmeng Sun ◽  
Lin Lin ◽  
...  

A cellulose carbonaceous aerogel/MnO2 ultrathick electrode with a unique low curvature, porous carbon thin-walled tube array structure was obtained from natural wood using a simple top-down approach.


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