Nondestructive Evaluation of FRP Design Criteria With Primary Consideration to Fatigue Loading

Design of FRP tanks and pressure vessels is based on criteria developed in the late 1960s using materials and procedures that represented the state of the art at the time. Maximum strain has been the controlling factor selected for the design of these vessels at an allowable level of 0.001. With the development of newer materials and systems with recorded performances of better than 0.001 this is now an inefficient limit in the design. Tests performed in the programs described in this paper indicate that newer materials perform well at higher strains. Results of strength tests performed here indicated that strains of 0.002 to 0.003 or better are possible in the safe design of tanks and pressure vessels. In addition, more accurate determination of design limits is possible if methods like acoustic emission are incorporated in the design process.