Device for generating specific local geometric initial defects on outer surface of thin shell structure

Abstract

The invention discloses a device for generating specific local geometric initial defects on the outer surface of a thin shell structure, and belongs to the technical field of structural engineering. The device comprises a fixed magnet, a telescopic rod, a fixed rod, a connecting rod, a sliding rod, an external load and a fixed pulley; a long hole is formed in the fixed rod; the fixed magnet is fixed at the top of the side wall of the fixed rod through the telescopic rod and is used for adsorbing the whole device on a testing machine; the connecting rod is fixed with the long hole of the fixed rod through a bolt; a sliding block on the sliding rod is matched with a sliding groove in the connecting rod, so that the sliding rod moves in the axial direction; and the external load is wound around the fixed pulley through a tether to be connected with a fixing plate, the weight of the external load is converted into axial thrust to the sliding rod through the fixed pulley and the tether, and along with movement of the sliding rod in the length direction of the sliding groove, a pressing head achieves fixed-point loading on the surface of the thin shell, so that a needed pit is formed. According to the device, the pit defects with variable positions, angles and depths can be quantitatively generated, and the device is used for quantitatively evaluating the influence of initial defect parameters on the structural bearing capacity.

Description

technical field [0001] The invention belongs to the technical field of structural engineering, and in particular relates to a device for generating specific local geometric initial defects on the outer surface of a thin shell structure. Background technique [0002] Thin shell structures are widely used in construction, aerospace, shipbuilding, automobile manufacturing and other fields due to their light weight, compact structure, and good load-bearing performance. The real thin shell structure inevitably produces local geometric initial defects on its outer surface due to manufacturing errors, external forces or corrosion. The geometric initial flaw is a key sensitive parameter affecting the strength and stability of the structure, which makes the bearing capacity of the actual structure often smaller than the ideal design load, thus affecting the safety of the structure. Both patent CN107716622 A and patent CN 212419173 U have designed repairing devices for local depressi...

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Problems solved by technology

However, this prediction method is only for simulation analysis, and it needs to be verified by experiments to ensure the reliability of this method.

Usually, when conducting defect-sensitive experiments, it is often necessary to repeat the experimental research after generating different degrees of depressions on the surface of the thin shell, which makes the experimental process very cumbersome

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