A test method for visual documentation of micro-cracks during tensile coupon testing includes the steps of: assembling a test unit; inserting a carbon-reinforced composite specimen having a prepared edge into the tensile coupon testing machine; illuminating the prepared edge of the specimen with a camera...http://www.google.com/patents/US7080561?utm_source=gb-gplus-sharePatent US7080561 - Visual documentation of micro-cracks during tensile coupon testing
