<p>Metal forming is a complex, multistage process that induces cumulative damage within materials. Preventing failure during forming operations is essential for process optimization, product quality, and cost control. This study presents a numerical modeling approach for simulating damage evolution in 7075-T6 aluminum alloy using an improved Lemaitre damage model. The model incorporates a damage variable into the Helmholtz free energy, with the plastic component driving degradation, leading to a physically consistent and smooth damage evolution law. A user-defined material subroutine (UMAT) was developed and implemented in Abaqus to integrate the proposed constitutive model. Through uniaxial tensile and cyclic loading--unloading tests, the damage parameters were calibrated using an elastic modulus degradation method. Numerical simulations of tensile specimens and a typical bending forming process were conducted to validate the model’s accuracy in predicting force--displacement responses and fracture locations. The improved Lemaitre model outperformed the classical version, demonstrating superior accuracy in capturing mechanical responses and failure behaviors under both uniaxial tension and complex bending stress conditions.</p>