This study explores the relationship between impact severity and resulting pulmonary contusion (PC) for four impact conditions using a rat model of the injury. The force–deflection response from a Finite Element (FE) model of the lung was simultaneously matched to experimental data from distinct impacts via a genetic algorithm optimization. Sprague-Dawley rats underwent right-side thoracotomy prior to impact. Insults were applied directly to the lung via an instrumented piston. Five cohorts were tested:​ a sham group and four groups experiencing lung insults of varying degrees of severity. The values for impact velocity (V) and penetration depth (D) of the cohorts were Group 1, (V = 6.0m·s­⁻¹, D = 5.0mm), Group 2, (V = 1.5m·s­⁻¹, D = 5.0mm), Group 3, (V = 6m·s­⁻¹, D = 2.0mm), and Group 4, (V = 1.5m·s­⁻¹, D = 2.0mm). CT scans were acquired at 24 h, 48 h, and 1week post-insult. Contusion volume was determined through segmentation. FE-based injury metrics for PC were determined at 24 h and 1week post-impact, based on the observed volume of contusion and first principal strain. At 24 h post-impact, the volume of high radiopacity lung (HRL) was greatest for the severe impact group (mean HRL = 9.21 ± 4.89) and was significantly greater than all other cohorts but Group 3.