Shaping technologies for manufacturing noise insulation casings of turbojet engines

Abstract

The article discusses questions of shaping honeycomb panels for turbojet engine noise insulation casings. Various types of structures and materials used for manufacturing honeycomb panels are presented. Samples were tested to determine mechanical characteristics. The technology of manufacturing honeycomb panels was determined by the value of relative elongation. The main rejection criteria in forming panels on bending and stretching presses were reviewed. The process of shaping honeycomb panels using computer numerical control (CNC) equipment was analyzed. Force parameters of the shaping process required for the assessment of the stress-strain state and obtaining the control program were determined. The values of the spring action were calculated for single-layer and double-layer panels using the A.A. Ilyushin unloading theorem. It was found that the springing of single-layer and two-layer panels differs due to the magnitude of the generalized rigidity. The value of springing is determined by the known height of the honeycomb panel. Designs of honeycomb panels with different positions of the middle layer along the height of the panel are given. Graphs showing the dependence of the punch radius adjusted for the value of springing on the radius of the part for various types of structures from titanium alloys and stainless steels are presented.

Keywords

• honeycomb panel
• double-layer structure
• shaping
• honeycomb filler
• stress-strain state
• rejection criteria
• springing
• cnc equipment