Lightweight Design Method Research Articles

A hybrid method of modified NSGA-II and TOPSIS for lightweight design of parameterized passenger car sub-frame

This paper presents a hybrid method integrating modified NSGA-II and TOPSIS, used for lightweight design of the front sub-frame of a passenger car. Firstly, the FE model of the sub-frame is constructed and is validated by modal test. Then, the strength performance of the sub-frame is analyzed under four typical load conditions consisting of braking, acceleration, steady state cornering and vertical bump. After that, a parameterized model of the sub-frame, in which 12 geometric parameters are defined as design variables, is developed based on the mesh morphing technology. Subsequently, modified NSGA-II is employed for multi-objective optimization of the sub-frame considering weight, maximum von-Mises stress and first order natural frequency as three conflicting objective functions. Accordingly, a set of Pareto-optimal solutions are obtained from the optimization process. Finally, the entropy weight theory and TOPSIS method are adopted to rank all these solutions from the best to the worst for determining the best compromise solution. In addition, the effectiveness of the proposed hybrid lightweight design method is demonstrated by the comparisons among baseline design and optimum solutions.

A lightweight and support-free design method for selective laser melting

Topology optimisation is an effective approach to design extreme lightweight components. However, most of the resulted optimum lightweight components usually have complex structures which cannot be produced successfully by traditional manufacturing processes. Selective laser melting is one of the additive manufacturing processes. It shows powerful capacity in the manufacturing of metal components with complex structures. Therefore, the combination of topology optimisation and selective laser melting shows a promising prospect for metal components. However, support structures were usually introduced during the selective laser melting manufacturing process, which resulted to some disadvantages, for example, the support structures are generally difficult to remove from the original components because it is difficult to clamping and machining. Therefore, a design method was proposed in this study, named lightweight and support-free design method, the detailed design process and advantages were presented. In the design process, topology optimisation was applied to realise lightweight design, and support-free design process was developed to meet the support-free requirement. Finally, as a case, a cross-beam component was designed using the proposed method, and the final model was produced successfully using selective laser melting process. The case study result verified that the proposed design method is effective to design lightweight and support-free industrial metal components for SLM process.

Structural optimization methods of nonlinear static analysis with contact and its application to design lightweight gear box of automatic transmission of vehicles

In this paper, we consider lightweight design methods for gear box of automatic transmission of vehicles with contact constraints. Lightweight design is a fundamental requirement for protecting the environment and improving fuel economy. In addition, durability is another important requirement for safe driving. However, in the design of automatic transmissions, these two requirements are usually in a trade-off relationship and engineers spend a long design study time. This paper deals with design approaches using structural optimization method to design lightweight structures and to minimize stress with contact constraints. Stress with contact constraints is solved using the finite element method. Three different structural optimization methods, topometry, topography and freeform optimization, are applied for the design of a lightweight gear box of an automatic transmission. The optimization results show that the optimization methods successfully found the lightweight gear box design and can be used at the early stage of the design process of automatic transmissions.

Towards low-carbon product architecture using structural optimization for lightweight

Carbon emission has become a recent global concern for green manufacturing. Production is one of the main sources of carbon emission. As the design of a product determines over 70 % of its life cycle costs, with extensive impacts on the environment, it is important to decrease the product carbon footprint in the product design stage. As the activity data is directly related to the mass of the product, the lightweight of product is a valid approach to low-carbon footprint. However, the existing lightweight design method primarily takes structure or material into consideration without the consideration of environmental factors. The product lightweight design under the low-carbon footprint constraint is proposed in this paper, which serves low-carbon footprint as an important benchmarking for product performance. This paper then presents a general lightweight design for product low-carbon footprint through structural optimization. The design of a cold heading machine is used to demonstrate the proposed methodology.

Construction of computer-aided industrial design system based on agility

Industrial design is one of most creative human activities and it is a process to solve problems of uncertainty. Agile methods of adaptive ideas and human-centred thinking provide references for the solving of industrial design problems. This paper borrowed agile theories from other relevant fields and evolved the principles of agile industrial design-based agility. The first principle is people-oriented design and building a self-organising team. The second is adaptive design and steadily give valuable designs. The third is adopting light-weight design methods or techniques. The final principle includes some practices. Based on the above, computer-aided industrial design system was constructed for building the platform for computer-aided design and design information management. This platform helped to explore design ideas to the utmost. The core modules of the system consisted of three parts - implicit knowledge track of creative thinking, clients involving in design, computer-aided colour design, and design practices templates.

Lightweight Investigation of Extended-Range Electric Vehicle Based on Collision Failure Using Numerical Simulation

The total weight of Extended-Range Electric Vehicle (E-REV) is too heavy, which affects rear-end collision safety. Using numerical simulation, a lightweight method is designed to reduce E-REV body and key parts weight based on rear-end collision failure analysis. To calculate and optimize the performance of vehicle safety, the simulation model of E-REV rear-end collision safety is built by using finite element analysis. Drive battery pack lightweight design method is analyzed and the bending mode and torsional mode of E-REV before and after lightweight are compared to evaluate E-REV rear-end collision safety performance. The simulation results of optimized E-REV safety structure are verified by both numerical simulation and experimental investigation of the entire vehicle crash test.

Lightweight Design of Rear Axle Housing Based on FEM

A lightweight design method is presented which depends on Finite Element Method (FEM).The goal of auto parts` lightweight design is realized based on results of mechanical calculation meanwhile combining experimental results from FEM. As an application of this method, a light truck`s rear axle housing is re-designed and related standards are satisfied. This method is of important science value and guidance meaning in many engineering fields besides in auto industry on the basis of improvement as well as rational application.

A Light-Weight Design Method for Vehicle with Welded Structure Based on Surrogate Model

In this paper, a multi-disciplinary optimization frame considering weld fatigue constraints is constructed based on kriging surrogate model in order to improve the fatigue reliability of vehicle structures. Under this frame, kriging surrogate model is used to construct weight, strength, stiffness, frequency, fatigue life responses for optimization, which improves effectively the computing efficiency. For weld fatigue analysis, master S-N curve method in AMSE criterion is used for reliable fatigue life. The curb girders of a high-speed train are taken as an example, a light-weight optimization model considering static strengthen and weld fatigue constrains is constructed and solved by use of submodelling technology under the proposed optimization frame. After optimization, the weight of the curb girders is reduced about 33% from 1.73 ton to 1.16 ton. These results show the proposed optimization method is effective, and provide the preference for the light-weight design of high-speed trains.

Lightweight design of an in-wheel motor using the hybrid optimization method

An increase in the unsprung mass is a critical issue for an electric vehicle driven by an in-wheel motor. The mass increase will cause the ride quality and comfort to deteriorate. To decrease the unsprung mass, a hybrid lightweight design method including size optimization and topology optimization is employed for the in-wheel motor. The two optimizations are carried out in sequence. First, the finite element method, the response surface method and the particle swarm optimization algorithm are employed in the size optimization design of the in-wheel motor. After this step, the mass of the in-wheel motor is reduced to 2.7448 kg, while its rated torque and losses are almost unchanged. Second, according to the above optimization results, topology optimization using the method of variable density is employed for the supporting frame of the stator of the in-wheel motor, which is the non-magnetic area. The material which is grade 45 steel is analysed. The optimization results show that, after optimization and treatment, the mass of the supporting frame is reduced to 1.069 kg, i.e. 63.11% lighter than before. Then, structural strength verification is carried out. Considering the above two optimization steps synthetically, the total mass of the in-wheel motor with a grade 45 steel supporting frame is reduced by 3.5547 kg, which means that it is 13.623% lighter than the original structure. Calculation of the transient torque and losses show that, after optimization, the total loss is reduced by 1.87%, and the torque by only 1.8%. Therefore, the hybrid optimization method studied in this paper works well for the lightweight design of an in-wheel motor.

Lightweight Design Methods in Integrated Practices

Lightweight Design Methods in Integrated Practices

A New Design Method of Body-in-White Lightweight Considering NVH Performance

With the development of the auotomobile industry, the body-in-white has to meet the dual requirements of lightweight and NVH performance. This study put forward a new lightweight design method considering NVH performance. An example of lightweighting a non-load-bearing body-in-white was given to illustrate the design flow of this method and certificate the effectiveness and applicability. In order to accurately find out the neutral contribution panels which almost have no influence on the interior acoustic field, a new parameter, the weighted acoustic contribution, was introduced to analyze and evaluate the panel synthetical acoustic contribution to multiple peak frequency at multiple field points. Consequently the whole body-in-white’s weight was reduced by 14.673kg and the interior acoustic field remained basically unchanged.

Topology Tailoring Method of TWB Autobody Parts Based on HyperWorks

In the paper, a lightweight design method for tailor-welded blanks (TWBs), termed as Topology Tailoring Method (TTM), is proposed, which is based on topology optimization philosophy and in which the variable density method is employed so as to reach the goal of the smallest structure strain energy. By using this method, a TWB autodoor subjected to a specific working condition is topologically optimized in HyperWorks, thus obtaining the more lightweight autodoor. At last, a side impact simulation of the autodoor is demonstrated, thus showing the effectiveness of the method.

Lightweight design of vehicle components based on strengthening effects of low‐amplitude loads below fatigue limit

ABSTRACTA new lightweight design method for vehicle components is proposed based on the strengthening effects of low‐amplitude loads below the fatigue limit. The new method is technically based on the strength feature of strengthening and damaging of vehicle components under loading spectrum, while combining dynamic strength equations with the residual strength of vehicle components. It ensures the maximum exploitation of the material's strength potential and fully realises the lightweight design of vehicle components at a low cost. As an application of the new lightweight design method, a light truck's front axle was redesigned. The lightweight potential of the front axle was first estimated by fatigue and static strength experiments of four‐point bending. Then the lightweight design was realised by finite element analysis and experimental results. The weight of this front axle was reduced by 5.5 kg.

Design of Suspension Components Considering Special Event Loading

Abstract In order to guarantee resource-saving and environment-friendly mobility for the future, the automotive industry adopts more and more new technologies. In this paper, a holistic design process for suspension components is introduced in which modern light-weight design methods and optimization tools are included. An example illustrates how fatigue analysis and testing have to be carried out to further ensure quality and reliability of the components.