Damage repairing method for single-closed-cavity foam sandwich structure

Abstract

The invention provides a damage repairing method for a single-closed-cavity foam sandwich structure. The method comprises the steps of determining a fault area of a paddle; wherein the fault area comprises a debonding area; uniformly setting glue injection holes in the fault area; injecting a preset amount of repairing glue into the glue injection hole based on the total glue injection amount; wherein the total glue injection amount is determined based on the weight of the paddle; pressurizing and standing the fault area of the blade based on a skin repair tool; compared with a traditional composite material blade repairing scheme, the repairing method has the advantages that the problem that the blade is overweight due to glue injection is effectively avoided, and the problem that the glue joint strength is reduced due to skin collapse and wrinkles in a foam core butt joint area caused by traditional foam patching is solved.

Description

technical field [0001] The application belongs to the technical field of composite material blade repair, and in particular relates to a method for repairing damage of a single closed-cavity foam sandwich structure. Background technique [0002] The main and tail rotor blades of composite materials belong to the single closed cavity foam structure, and the foam filled inside the blades is polyurethane foam, which is compressed and molded under certain temperature and pressure. The role of the foam is to maintain shape, reduce weight and provide internal pressure. During the use of composite material blades, the skin and internal foam are prone to damage. The intuitive appearance is that the knocking sound is abnormal, and the knocking sound is abnormal / disbonded. Analyze the possible areas of disbondment: First, skin and foam detachment Sticky, the second is that the foam itself has instability / cracks. The instability / failure of the foam after compression molding is mainly...

AI Technical Summary

Problems solved by technology

The instability / failure of the foam after compression molding is mainly caused by the following two situations: one is that the pressure is normal, but the compressive strength of the foam is insufficient; the other is that the pressure is too large, exceeding the compressive bearing capacity of the foam

[0003] For the debonded area, the commonly used repair method is to repair the skin and foam by local excavation, but the newly filled foam is prone to edge collapse, and the skin to be repaired is prone to serious defects such as steps. During the secondary curing process, it is very easy to cause debonding of the clad iron, and new faults

[0004] Of course, glue injection repairs will also be considered, but traditional glue injection repairs generally use glue injection guns, the pressure of glue injection is uncontrollable, and it is easy to cause secondary debonding damage; Problems such as overweight blades

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