Skin strain fields at the shoulder joint for mechanical counter pressure space suit development

High-resolution human skin strain field data is presented for the shoulder joint measured using three-dimensional digital image correlation (3D-DIC). Developing mechanical counter pressure (MCP) space suits requires detailed understanding of human skin deformation at joints in order to fit and create MCP without restricting human mobility or increasing human energy expenditure. Previously, skin strain for this application has been measured for one degree of freedom joints such as the elbow and knee. Now using four stereoscopic camera pairs for 3D-DIC (8 cameras), a strain field comparison is made between various motions of the shoulder joint. This paper specifically compares shoulder abduction and flexion in the context of realizing a MCP space suit designed for planetary exploration. Methods are explained to perform 3D-DIC using multiple stereoscopic camera pairs for complex joint motions. These results are important to develop MCP space suits that allow upper-body mobility. The discussion of the results provides insight and data for designing optimal textile patterning for skin-tight space suits at multiple-degree of freedom joints.