An Experimental Method for Obtaining Fatigue Small Cracks in Sheet Metal Parts Using Cellulose Acetate Film Replicas

Abstract

The invention discloses an experimental method using cellulose acetate film replication to acquire fatigue small crack condition of sheet metal and relates to the field of mechanical structure fatigue. The experimental method includes: during front-back replication, adopting a big hairbrush for quick brushing to enable a film to be pasted on the sheet metal at a time, and using a small hairbrush to dip acetone to remove bubbles from left to right, wherein the moving direction of the hairbrush is perpendicular to a load bearing direction of the sheet metal, and the moving direction of the hairbrush and the surface of the sheet metal form 20 degrees; during replication of the side face of the sheet metal, adopting the small hairbrush to dip acetone, enabling the hairbrush to contact with thesheet metal above the film to enable the acetone to flow down the film and to enable the film to be pasted on the side face of the sheet metal, and pressing the hairbrush to squeeze out the bubbles in the film; during extracting of the film from the front and the back, using a finger to poke the film exposed on the outer side repeatedly to enable the film to slowly expand; during extracting of the film from the side face, using the hairbrush to slightly brush to enable the film to warp up, and using a finger to poke the film exposed on the outer side repeatedly to enable the film to expand. By using the experimental method, replication success rate is increased, and experimental accuracy is improved.

Description

technical field [0001] The invention relates to the field of mechanical structure fatigue, in particular to an experimental method for obtaining small fatigue cracks of metal plate parts by replicating a cellulose acetate film. Background technique [0002] Replica technology is a method of preparing samples for electron microscopy and a means of obtaining the surface crack morphology of structural parts. Small cracks in sheet metal can be obtained by using cellulose acetate film replica method. The advantage of the cellulose acetate film replica method is that the replicated film in the experiment can be permanently preserved, which is convenient for observation and research with a microscope in the future; at the same time, the complete small crack morphology can also be obtained through the replica method. The method is simple to operate, and the air-drying time of the film is short, which is suitable for the replica test of fatigue small cracks. [0003] Fatigue cracks...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the defect problems such as film rupture, air bubbles blocking cracks and serious film shrinkage in the process of replicating the four sides of metal plate parts by using cellulose acetate film, and to provide a method to obtain Experimental method for small fatigue cracks in sheet metal parts, improving the success rate of the replica method and increasing the accuracy and reliability of test results

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