Cure and Health Monitoring

AbstractThe smart monitoring system has evolved due to advances in sensors, sensing methods, and communication technologies. The sensing function involves sensors, signal sources, and signal detectors. Measured data are analyzed by a signal processor using an appropriate analytical approach. The analyzed results are reported to operators or observers. In the old days, human beings performed these functions. Today, they are replaced by sensor devices, computers, and communication networks. For example, a fire alarm system consists of a temperature sensor, a microcomputer, and an alarm. Furthermore, the recent development in sensors and computers make these devices so small and light that they can be integrated into structures. An integrated monitoring system makes the materials and structures “smart”, and then it can be called a “smart” monitoring system.The smart monitoring system has mainly two practical, commercial targets. One is “manufacturing process monitoring” and another is “health monitoring.” The former is a technique for monitoring the state of materials in the manufacturing process. Monitoring of the molding process for thermosetting polymers, called “cure monitoring,” has been especially focused on polymer matrix composites (PMCs). In manufacturing process monitoring, the chemical and physical state of materials and the integrity of products are monitored. The collected data can also be used for optimal control of the forming process to improve efficiency. Monitoring the integrity of the product makes it unnecessary to inspect after manufacture. Then, the manufacturing cost can be reduced by introducing this technique. Health monitoring, on the other hand is a technique for monitoring the condition of materials and structures in operation. In the last decade, health monitoring has become a hot issue especially in aerospace and civil structures. These structures suffer from mechanical and thermal fatigue, long exposure time, and natural disasters such as earthquakes and typhoons. Thus, periodic inspections are required to maintain the safety of these structures adequately. However, the inspection cost of large structures is very high, and operation must be interrupted during the inspection. Therefore, real‐time health monitoring promises to reduce maintenance costs and to improve reliability. By combining these two monitoring techniques, it is possible to monitor the state of materials and structures from their beginnings to their ends. This means that the quality of products can be ensured continuously at low cost. Therefore, the idea is a very attractive solution for reducing the total cost of ownership, including the price, maintenance, and operating cost. Details on these tapes are given.