Fang, Xiangfan
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Publication Access status: Metadata only , A new resistance insert spot welding method for injection-molded FRP–steel component(2024); For weight reduction, multi-material designs comprising metal and fiber-reinforced plastic (FRP) components in vehicle body structures have been increasingly used. However, the commonly used resistance spot welding (RSW) technology for car body assembly cannot be employed to join sheet metal and FRPs, limiting the use of FRPs. To solve this problem, a novel resistance insert spot welding (RISW) technique was developed in this work for RSW of steel parts and FRP structure parts made by injection molding. Small inserts were developed by using finite element method and experiments that may be welded to different micro-alloyed and dual-phase sheet steels using the projection welding method. The usual flange width of original equipment manufacturers could be kept unchanged. Using the developed insert and welding parameters, the maximum temperature in the FRPs surrounding the inserts was limited to 255 °C, minimizing the damage to polyamide 6 (PA6) material (with 40 wt% glass fiber). A weldability range between 2.5 and 7 kA could be achieved. The joining strength of RISW between a micro-alloyed HC340 steel in 0.75 mm and 1.5 mm thickness and a 2.5 mm/3.0 mm PA6-GF40 material is 20 to 80% higher than self-piercing riveting (SPR). For high-speed loading, RISW strength increases by 39 to 56% further. Finally, RISW was successfully applied to an FRP–steel roof-frame sub-assembly that consists of 19 simultaneously integrated inserts, achieving 10% weight reduction.Source Type:Article2 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , A rate-dependent damage mechanics model for predicting plasticity and ductile fracture behavior of sheet metals at high strain ratesPublisher Copyright: © 2024 The Author(s)Source Type:Article2 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Elastokinematic design and optimization of the multi-link torsion axle – a novel rear axle concept for BEVs(2024); This work describes the elastokinematic design and optimization for a new, package space saving rear suspension especially intended for small battery electric vehicles. Mainly for reasons of cost and weight efficiency, the twist-beam axle is widely used, especially in the A and B segments. One of the main disadvantages of twist-beam axles is that they limit the rear package space because of the torsion profile. The basic idea of this work was to reverse the installation direction of the twist-beam axle to create an additional package space for the battery. To obtain an optimized elastokinematic design, a new algorithm was introduced that allows modeling of the elastokinematic behavior of the new mechanism. A Pareto optimization of the body connecting bushing was performed, revealing that a specific spatial orientation enables effective compensation for camber compliance deficits. Finally, the Pareto-optimized elastokinematic design was compared to compliance measurement results of a prototype vehicle equipped with the new suspension concept.Source Type:Article5 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Evaluation of Vehicle Lateral and Longitudinal Dynamic Behavior of the New Package-Saving Multi-Link Torsion Axle (MLTA) for BEVs(2024); To increase the package space for the battery pack in the rear of battery electric vehicles (BEVs), and thus extend their driving range, a novel rear axle concept called the multi-link torsion axle (MLTA) has been developed. In this work, the kinematic design was extended with an elastokinematic concept, and the MLTA was designed in CAD and realized as a prototype. It was then integrated into a B-class series-production vehicle by ADDing masses in different locations of the vehicle to replicate the mass distribution of a BEV. Both objective and subjective vehicle dynamic evaluations were conducted, which included kinematic and compliance tests, constant-radius cornering, straight-line braking, and a frequency response test, as well as subjective evaluations by both expert and normal drivers. These test results were analyzed and compared to a production vehicle. It can be concluded that the vehicle dynamic performance of the MLTA-equipped vehicle is, overall, 0.67 grades lower than that of the comparable production vehicle on a 10-grade scale. According to OEM experts, this deficit can be eliminated by tuning the different components of the MLTA and meeting the tolerance requirements of series production vehicles.Source Type:Article1 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Local Reinforcement of a Fuel Cell End Plate for Package Improvements Using Steel–Aluminium Hybrid-Casting TechnologyIn this research work, a method for integrating a local reinforcement structure in a medium-pressure plate (MPP) for fuel cell electric vehicle (FCEV) applications was developed using steel–aluminium hybrid-casting technology. Using this technology, it is possible to create a bonded enclosure of a steel reinforcement patch with the cast aluminium pressure plate to increase its stiffness and achieve 15% package space savings. A load-compliant, manufacturable patch was chosen and optimised for maximum stiffness gains using non-linear static finite-element (FE) calculations. Special form and process requirements due to hybrid-casting technology were examined and secured with casting simulations. The reinforcement patch was manufactured and coated with a unique aluminium–silicon coating enabling a ductile material connection between the steel and aluminium, and casting trials were conducted to create prototypes. Additionally, the insulating plastic layer on top of the metallic pressure plate carrier was substituted from costly short-fibre-reinforced high-performance plastic to cheaper and stiffer glass-mat reinforced thermoplastic material. Finally, the new hybrid MPP was tested mechanically, and the FE-Model was verified. In summary, through the package gain, 2.1 kW more power output and 11% less weight could be achieved while remaining stiffness neutral.Source Type:Article5 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Resistance insert spot welding: a new joining method for thermoplastic FRP–steel component(2023); Recently, multi-material designs consisting of metal and FRP components are being increasingly used in vehicle body structures to reduce weight and thus energy consumption and emission. Because the most commonly used resistance spot welding (RSW) technology for body assembly cannot be applied to join sheet metals and FRPs, the usage of FRPs is strongly limited. Therefore, a new resistance insert spot welding (RISW) method was developed. During the manufacturing process of FRPs, here compression molding of PA6 GF40 materials, specially designed steel inserts are directly integrated into the FRP part. Later, via the steel inserts, the FRP part can be spot welded to other steel parts in the structure. In this work, the design and development process of RISW is presented. Starting with the design concept of inserts, welding tests were conducted, and the parameters for the welding simulation were calibrated. After that, the detailed insert design was performed using welding simulation and tests with several restrictions, such as insert dimensions, the temperature in FRPs, the weldability range, and joining strength. In the end, an appropriate insert geometry was found, which met all requirements. The mechanical properties of RISW joining are better than or equal to those of SPRs. The new RISW technology was also demonstrated on a real vehicle component. A seat cross member was designed using FRP with 42% weight reduction and produced by compression molding with 30 simultaneously integrated inserts. The cross member was finally successfully welded to a steel closing plate using RISW.Source Type:Article1
