【国外标准】 Standard Practice for Tensile Properties of Tapered and Stepped Joints of Polymer Matrix Composite Laminates

5.1 This test practice is designed to produce tensile property data for material specifications, research and development, quality assurance, and structural design and analysis. Factors that influence the tensile response and should therefore be reported include the following: materials (laminates and adhesive), methods of material preparation including surface preparation prior to bonding, lay-ups, specimen stacking sequence, joint taper ratio or step length, ply overlap length, material relative thicknesses and stiffness of the parent and repair laminates, adhesive bond stiffness, specimen preparation, specimen conditioning, environment of testing, specimen alignment and gripping, speed of testing, time at temperature, void content, and volume percent reinforcement. Properties in the test direction, which may be obtained from this test practice, include the following:5.1.1 Ultimate tensile strength (based on the nominal parent material thickness), (Fptu).5.1.2 Ultimate tensile strength (based on the nominal repair material thickness), (Frtu).5.1.3 Ultimate running force per repair ply, (Nj).1.1 This test practice defines the procedure for determination of the tensile strength of a tapered or stepped joint of polymer matrix composite materials. It is applicable to secondary bonded or co-bonded laminates with either unidirectional plies or woven fabric reinforcements. The materials to be bonded may be different material systems. In the bondline, a separate adhesive material may or may not be used (example: adhesives may be used with a prepreg system or may not be used with a wet lay-up repair system). The range of acceptable test laminates and thicknesses is described in 8.2.1.1.2 This practice supplements Test Method D3039/D3039M for tensile loading. Several important test specimen parameters (for example, joint length, ply overlaps, step depth, and taper ratio) are not mandated by this practice, however, these parameters are required to be specified and reported to support repeatable results.1.3 Unidirectional (0° ply orientation) tape composites, textile composites, as well as multidirectional composite laminates, can be tested.1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.1.4.1 Within the text the inch-pound units are shown in brackets.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.