Impact transducer for non-destructive testing by the local method of free vibrations of products made of polymer composite materials

Abstract

This utility model is a non-destructive testing device and can be used in conjunction with flaw detectors for testing polymer and composite materials to detect internal manufacturing and operational defects. The impact transducer operates by inducing free, damped elastic vibrations in the test object through periodic impacts of a striker against the test surface. These vibrations are then captured by a built-in microphone and subsequently analyzed. The transducer offers a wide range of adjustments. The distance from the striker surface to the test surface can be quickly and easily adjusted using a special screw located inside the housing. Replaceable strikers of various shapes and materials can be used (depending on the parameters of the structures being tested).The use of various interchangeable profiled pads for inspection of radius zones has been implemented. Since the striker impact zone on the inspection surface is not obscured by the transducer housing, defect boundaries are more accurately determined. The transducer's overall design allows inspection in any spatial position: downward, vertical, overhead, etc.

Description

[0001] This utility model relates to non-destructive testing using a local free vibration method. The impact transducer utility model can be used in conjunction with flaw detectors for testing polymer composite materials to detect internal manufacturing and operational defects. The impact transducer's operating principle is based on the excitation of free, damped elastic vibrations in the test object by periodically striking the striker against the test surface. These vibrations are then recorded by a built-in microphone and subsequently analyzed.

[0002] The PDU-3 impact transducer with a microphone is known for the AD-60S flaw detector (Lange Yu.V. Acoustic low-frequency methods and means of non-destructive testing of multilayer structures. Moscow: Mashinostroenie, 1991, p. 155). This device was chosen as the closest analogue (prototype). Disadvantages of the prototype include strictly specified parameters of the oscillating system, limiting the transducer's scope of application, obstructed visibility of the striker's impact point on the testing surface, and the inability to inspect radius zones.

[0003] The technical result observed during the implementation of the utility model is the expansion of the scope of application of the converter for monitoring various structures.

[0004] The technical result is achieved through the design of an impact transducer for flaw detectors that utilize the local free-oscillation method for non-destructive testing of polymer composite materials. The transducer consists of the following main elements: a housing with a moving part containing an electromagnetic actuator with a rod and return spring. The lower part of the rod is threaded to accommodate strikers made of various materials and shapes.

[0005] The converter has an adjustment screw for quickly adjusting the distance from the striker to the surface on which the impacts are made, a microphone installed in the lower part of the housing, an LED in the upper part of the housing for automatic signaling of a defect and a connector for connecting to a flaw detector, as well as replaceable pads, which can be either flat or with a concave or convex profile for testing curvilinear structures.

[0006] The utility model is explained by a general view drawing and a photograph of the converter (Fig. 1a, 1b), images of convex and concave overlays (Fig. 2a, 2b).

[0007] The transducer consists of a housing 1 with a movable part 2, an electromagnetic actuator 3 with a rod 4, a striker 6 and a return spring 5, located in the movable part 2 of the housing. Inside the housing there is an adjusting screw 7, with which the distance from the striker 6 to the testing surface is changed. The rod 4 has a thread, which allows for screwing on strikers made of various materials and of various shapes. A cover plate 11 is screwed to the bottom of the housing with two countersunk screws. The cover plate can be either flat or with a different profile: convex (Fig. 2, a), concave (Fig. 2b) with the required radius. This allows for testing various complex curvilinear structures. In the upper part of the transducer there is a connector 10 for connecting to a flaw detector via a cable and an LED 9 for automatic signaling of defects. Elastic vibrations are received by a microphone 8, located inside the housing.

[0008] The converter operates as follows. An external generator (or a generator built into the flaw detector) sends rectangular pulses of a specific frequency and duration to an electromagnetic actuator 3. Typically, the operating frequency ranges from 1 to 10 Hz. The electromagnetic actuator drives a rod 4, which periodically strikes a striker 6 against the surface of the test object. This generates elastic waves, which are recorded by a microphone 8. The signal from the microphone is analyzed either by the flaw detector or by any other receiving device (oscilloscope, spectrum analyzer, etc.). Scanning the surface of the test object is performed manually, maintaining the required step and speed.

[0009] Thus, the implementation of this utility model expands the scope of application of the impact transducer. The oscillatory system can be customized to test structures made of various materials and shapes.

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