Material Testing & Selection
Stress Engineering Services (SES) provides laboratory testing services to measure material property data including chemistry, static tensile, creep, fatigue and other types of data that are needed to design and validate medical products. These data can be used to predict product performance before components are manufactured, thus helping to identify design problems early in the product development process, when design changes are more easily made. SES’s material testing services are closely integrated with our predictive engineering group so the right test data are available and in a form that can be easily used for design calculations.
Two fundamental elements of most mechanical design projects are solid mechanics and materials behavior. At a very basic level, solid mechanics involves understanding how the structure supports loads (e.g. stress = load/area). Materials behavior involves understanding the basic response of a material to these loads (e.g. material permanently deforms when stress exceeds yield strength). An understanding of both mechanics and materials is therefore necessary for successful mechanical design.
Because of our heavy involvement in polymeric part design, SES has developed a significant capability in both laboratory resources and engineering/materials science. The need for the supporting laboratory resource was a consequence of the fundamental lack of polymeric material property data in the open literature that could be used to support our design activity. The laboratory capability that SES has developed includes traditional testing such as material chemistry testing, static tensile testing, characterization of rheological properties, fatigue testing, creep and relaxation testing, testing of elastomers, etc. SES has also developed custom techniques for less-traditional testing such as high strain rate testing, multi-axial tensile testing, environmental stress crack testing, accelerated life testing, coefficient of friction testing, gas and water vapor permeability, etc. The development of new test methods is almost always driven by an engineering need, which is usually derived from a need to understand the attribute of a material as it affects the mechanical design of a product. This interdependence between mechanical design and materials behavior has bred a uniquely applied (and practical) type of material testing capability.