Acta Scientiarum http://periodicos.uem.br/ojs ISSN on-line: 1807-8664 Doi: 10.4025/actascitechnol.v44i1.60577 MECHANICAL ENGINEERING Acta Scientiarum. Technology, v. 44, e60577, 2022 Stress-strain analysis of the tow hook of a commercial truck by numerical simulations Alexandre Assis Rezende Santos * , Leomar Santos Marques, Marcus Vinicius Ferreira de Moura and Ricardo Rodrigues Magalhães Departamento de Automática, Universidade Federal de Lavras, Av. Doutor Sylvio Menicucci, 1001, 37200-000, Lavras, Minas Gerais, Brasil. *Author for correspondence. Email: alexrezendeufv@gmail.com ABSTRACT. Numerical simulations have been widely used in the industry, although with some limitations. One of these limitations is the fact that the thermal effects derived from component manufacturing processes are normally disregarded in the analysis. Thus, the main goal of this study is to evaluate strains near the weld beads of a geometric model for a truck tow hook using numerical simulations by finite element method, considering thermal loads applied before the field loading. To validate the simulation results, an experiment was performed using a tow hook found in a commercial truck. Strain gauge rosettes were placed on the body base plate, and a load of 181.050 N was applied to the hook. This loading was the result of a commercial truck being pulled on level terrain, simulating a normal operation condition of the tow hook. The Von Mises stress found in simulations was approximately 302.23 MPa at the same position where the strain gauges were glued, when the load was applied. The difference between the simulated and experimental values of the equivalent specific strains in the area of the weld beads was 19.2%, and the difference between the permanent displacement values, resulting from plastic strain, in the X-direction was 0.1%. These results justify conducting new studies involving numerical simulations and considering thermal effects on static and dynamic loads in the automotive industry. Keywords: Finite element method; plastic strain; strain gauge. Received on August 17, 2021. Accepted on October 21, 2021. Introduction Automotive components must be designed and manufactured properly and accurately to prevent possible failures under normal conditions of use. However, the guarantee that components will not fail in service is provided through strength and durability tests. These tests require time and money to obtain reliable results. To reduce product development costs and time, companies typically use resources derived from laboratory tests and numerical simulations. These simulations allow quickly changing the configurations of the numerical model and collecting data on the component. Nevertheless, in this type of analysis, the properties, manufacturing processes, and load conditions of the material should be studied. Numerical simulations provide faster results, but require calculating physical phenomena involved in the process, such as welding, at a high computational cost. To overcome this problem, simplified models are used, although without affecting the results. These simplified models are normally validated in experimental tests. In some cases, thermal analysis of a weld bead may determine the stress distribution in a part that is normally subjected to forces in the field. However, in most cases, the thermal input from the welding process of the part is disregarded, which may lead to inaccurate simulation results. Some simulation studies about welding processes have been conducted (Chen & Soares, 2021; Rong, Xu, Huang, & Zhang, 2018; Venkatarao, 2021; Farias, Teixeira, & Vilarinho, 2021; Evdokimov et al., 2021) to identify stresses and strains along the weld beads. In these cases, models are commonly simplified and optimized, and the thermal load and residual stress involved in the welding process are disregarded. Doerk, Fricke, and Weissenborn (2003) compared different methods and procedures for calculating surface stresses in welded joints. Some methods are used for stress linearization through plate thickness, what followed the guidelines from the International Institute of Welding (IIW) to analyze certain types of weld beads. Petracconi, Ferreira, and Palma (2010) conducted a study about the fatigue cracks initiation in the rear tow hook assembly of a passenger car. The authors compared experimental fatigue tests to numerical simulations