دانلود رایگان مقاله رادوم آنتن هواپیما UHF بر اساس تصویربرداری انتشار اولتراسونیک پالس اکو

Abstract

Most aircraft antennas are protected by radomes made of composite materials. However, antenna radome structures are easily damaged by external forces and internal manufacturing defects. To detect damage in the composite antenna radomes while in service, a full-field pulse-echo ultrasonic propagation imaging (PE UPI) system is proposed as an in situ non-destructive inspection technique, which is mobile inside a hangar. The radome is generally a double-curvature structure, and thus, a curvature compensation algorithm is also developed to increase damage visibility. The proposed hardware and software have been tested by detecting a resin rich region formed between the E-glass/epoxy plies. To visualize the damage, PE ultrasonic wave propagation imaging has been performed, and ultrasonic energy mapping has also been applied. A curvature compensating algorithm has been newly developed and compared for its performance in damage visibility improvement. To verify the size of the real defects of a UHF antenna radome, destructive testing has been performed by cutting the defect area, polishing the cross section and investigating the section using a 50× microscope. The results have shown the feasibility of the proposed PE UPI system and the inspection strategy as an in situ non-destructive evaluation technique for radome structures.

4. Conclusion

In this research, we proposed a full-field PE UPI system to inspect composite antenna radome structures using an INDE method, which is a rapidly growing field, such as the smart hangar or robotics-based NDE example shown in Fig. 1. The PE UPI system uses the through-the-thickness ultrasonic mode. We found that the curvature-induced global amplitude distribution caused by the changes in beam incident angle and wave travelling distance during the scan can shadow the damage and thus make it difficult to evaluate its exact size. Therefore, we proposed a curvaturecompensating algorithm, which was implemented in the pulseecho UPI system. As a proof-of-concept, the curvaturecompensated UWPI non-destructively visualized the manufacturing defect of the resin-rich region, and the measurements in the microscopic destructive test showed good agreement. Consequently, this paper proposed an INDE technique for curved radome structures based on the PE UPI system and showed satisfactory feasibility for field implementation.