PIEZOELECTRIC ARRAY FLEXIBLE SENSOR USING FEATURE GUIDED WAVES FOR DETECTING WELD SEAM DEFECT, AND DETECTION METHOD

摘要

The present invention discloses a piezoelectric array flexible sensor using feature guided waves for detecting a weld seam defect, and a detection method. The sensor comprises multiple piezoelectric units arranged in an array on a flexible substrate. Each piezoelectric unit is covered with a damping block, and surrounded by a sound-absorbing material. A housing of the sensor is sealed using a flexible protective film. Positive leads of the respective piezoelectric are connected in series to a logic switch and a delayer, and connected in parallel to a positive bus. The piezoelectric units are divided into three categories. The three categories of piezoelectric units respectively excite three different modes of guided waves, have different sensitivity to different types of defects, and are complementary to each other. The sensor selects, by using the logic switches, different piezoelectric array detection modes so as to meet weld seam detection requirements of surfaces of different curvatures and different structures. The delayers adjust an excitation time difference to combine and focus sound beams. The sensor has a simple structure and high adaptability and detection efficiency, is especially applicable to rapid in-service detection of long weld seams of large equipment, and is highly automated.