Experimental multiscale analysis of liver damage and failure process under compression.

BACKGROUND

To prevent abdominal organs' traumas in crash situations, the definition of efficient safety devices should be based on a detailed knowledge of human tolerance, i.e., injury mechanisms and related injury criteria. This knowledge should be based on experimental observation of these mechanisms through damage and failure analysis.

METHODS

In this study, 10 human cadaveric livers are uniaxially compressed using three different loading velocities (0.0013, 0.2, and 1 m/s). Injuries induced are analyzed at two observation levels through a macroscopic study of internal and external cracks and a histologic study of damage initiation.

RESULTS

Liver global behavior is similar for the three loading velocities, but loading rate seems to influence the stiffness and the severity of failure process. Macroscopic injury analysis showed four patterns of laceration because of organ spreading during its compression exhibiting liver structure incidence. Histologic analysis shows two different damage occurrences: microcracking and cavitation. The crack propagation is observed to occur preferentially within the lobules. Influence of the vascular system is also highlighted. Both macroscopic and histologic injuries obtained are relevant with those clinically observed under trauma situations.

CONCLUSION

Based on experimental investigation of human liver under compression, this work provides a multiscale evaluation of injury process coupling mechanical and histologic analysis. Injury mechanisms postulated involve vascular structures and capsule. All this information is essential for the design of dedicated behavior laws and finite element models.