Biomechanical approach for the assessment of contacts with deformable objects

Abstract

Forensic and biomechanical assessment in case of blunt force trauma can be a challenging task especially when deformable striking objects are used. Evaluations solely based on empirical knowledge can lead to misjudgments. Semi-quantitative and quantitative investigations give the forensic assessment a scientific basis comprising experimental and calculation methods. Based on a real case where a car wheel was used as a striking object, our work presents a simple test setup for contact force estimation in head contacts with deformable contact partners. Our approach combines experimental measurements using a single accelerometer and calculations applying the conservation of linear momentum and Newton's second law. Both experimental and calculation results are discussed in terms of validity, reproducibility, and plausibility. With regard to our case, we can conclude that the injury pattern without skull fractures does not confound multiple strikes with a wheel. Skull fractures and potential fatal injuries had not to be expected assuming a head-carcass contact in case of a non-supported head. The approach presented can be applied to any case where deformable or uncommon blunt objects are used.

Experimental characterisation of porcine subcutaneous adipose tissue under blunt impact up to irreversible deformation

“…Studies on different impact scenarios show that the superficial soft tissue layers can absorb between 35% up to nearly 70% of the impact energy [1][2][3][4]. However, the influence of the covering soft tissues on skeletal trauma, which can be essential for the reconstruction of blunt force attacks or the assessment of an assault as potentially life-threatening or not, is still not fully understood [5][6][7][8][9][10][11]. A promising tool for the evaluation of this influence is the finite element (FE) method, which has already been applied for the investigation of different impact scenarios in the field of forensic science [5,[12][13][14][15][16].…”