## 1 Introduction  
With the continuous growth of car ownership, automobile exhausts emit a large number of pollutants. Additionally, the fuel consumption problem is becoming increasingly serious. In order to reduce the environmental and energy problems caused by the development of the automobile industry, making an automobile lightweight has become one of the effective measures [1; 2; 3]. A suspension control arm has to bear and transfer various loads caused by road roughness and engine vibrations. Thus, its thickness is always set to be thicker to ensure vehicle safety, which leads to the weight of the suspension system also being greatly increased. Therefore, it is of great significance to carry out a lightweight design of the control arm on the premise of ensuring its stiffness, strength, and fatigue life [4; 5; 6]. Scholars have paid much attention to automobile lightweight solutions, including optimization design, the application of lightweight material, and advanced manufacturing processes. [PERSON] et al. [7] optimized the topology of an aluminum control arm and proposed the optimal material layout method based on load and boundary conditions, which achieved a mass reduction of 41% under the condition of satisfying the strength. [PERSON] et al. [8] replaced the aluminum used for the control arm with carbon fiber-reinforced polymer and carried out topology optimization. At the same time, under the conditions of multiple constraints including stiffness and durability, the weight was reduced by 30%. [PERSON] [9] changed the material of automobile B-pillar from metal to carbon fiber-reinforced polymer, which not only reduced the mass by 50.76%, but also greatly improved the crashworthiness. [PERSON] et al. [10] developed automobile hinge components with PA66 GF60 glass fiber-reinforced polyamide composite instead of ordinary steel. Topology optimization was carried out under a specific load to obtain the optimal size and minimum mass. [PERSON] et al. [11] designed a new single stamping control arm and achieved a mass reduction of 33.3% compared to the original one through topology optimization and size optimization. For engineering optimization problems, there are usually two or more objectives that need to be achieved. Generally, these objectives are in conflict with each other. Traditional single objective optimization often focuses on one key optimization performance while ignoring the correlation with the other performance. Multi-objective optimization methods are proposed to select the Pareto solutions in many engineering fields. [PERSON] et al. [12] designed a new bumper system composed of negative Poisson's ratio (NPR) beam and NPR absorber, and used a multi-objective optimization algorithm to search for the optimal structural parameters. The results show that the performance of pedestrian protection and vehicle crashworthiness was improved. [PERSON] et al. [13] used the multi-objective optimization method to optimize the passive suspension system of a whole vehicle model running on a random road, which achieved a reduction of 21.14% for the weighted mean square root of vertical angular velocity of the driver seat. Based on the Kriging surrogate model, [PERSON] et al. [14] used a multi-objective genetic algorithm to optimize the thickness of acoustic package material. Under the condition of ensuring that the acoustic performance of automobile acoustic package remained unchanged, the mass was reduced by 20.76%. [PERSON] et al. [15] optimized the thin-walled tube with the aim of maximizing specific energy absorption (SEA) and minimizing peak crushing force (PCF). Response surface methodology (RSM) was established to find the optimal configuration of the tube for improving the energy absorption characteristics of the thin-walled tube. Reliability is the probability that a product will not fail. The failure probability of the product is closely related with the uncertainty of design parameters [16; 17].