PSI - Issue 79

Giulia Morettini et al. / Procedia Structural Integrity 79 (2026) 440–448

444

In addition, it is necessary to know some fundamental parameters of the electronic component, which can be easily obtained from manufacturers’ datasheets: the mounting configuration, number of pins, weight, body and lead dimensions, and the mechanical characteristics of the lead materials. The proposed analysis is divided into two main phases, which separately examine the stresses induced by the curvature of the PCB and those arising from the dynamic behavior of the component. The results of these two analyses are then combined through the superposition of effects, in order to estimate the total accumulated fatigue damage. 3.1. Calculation of the Damage Due to PCB Curvature To evaluate the damage associated with the curvature of the board, it is first necessary to characterize the dynamic response of the PCB. This can be achieved through the use of commercial Finite Element Method (FEM) codes, which, starting from the physical and mechanical parameters of the board and the input acceleration PSD, allow for the determination of the displacement PSDs in each spatial direction, Fachri P. Nasution (2012). This stage represents the first step of the proposed workflow. The displacement PSDs can then be expressed in a simplified form through their Root Mean Square (RMS) values, equivalent to the standard deviation of the signal, providing a conservative estimate of the maximum expected displacement of the system along the three spatial axes. The result of this computation is a three-dimensional map, illustrated in Fig. 4a, describing, point by point, the maximum deformation of the PCB under the applied load. It is important to emphasize that this approach is inherently conservative. However, this is consistent with the aim of the proposed tool, which prioritizes computational efficiency and ease of use over absolute precision, being conceived as a qualitative design support tool. Based on the resulting deformation field, local displacements responsible for stresses in the component leads are analyzed. Specifically, at each point of the deformed surface, the direction of maximum slope is identified, and a plane is constructed along this orientation. The intersection of the surface with this plane provides a two-dimensional local representation of the deformation, as shown in Fig. 4b. Following the approach originally proposed by Steinberg (2000), the characteristic length of the component (the longer side of its body) is considered, and for the segment centered at the analysis point, the vertical and horizontal distances of its endpoints from the local deformation curve are computed. This procedure allows for the determination, at each point of the board, of the displacement differentials Δ x and Δ plan acting on the component terminals, representing the maximum deformation transmitted to the leads under the applied load, as illustrated in Fig. 4c.

Fig. 4. Workflow representation of the PCB curvature analysis: (a) RMS displacement map, (b) local 2D deformation section, and (c) estimation of relative displacements acting on component leads.