Review of Damage Tolerance for Composite Sandwich Airframe Structures

Abstract

The use of composite sandwich construction is rapidly increasing in current and future airframe designs especially for general aviation aircraft and rotorcraft. Typically, sandwich constructions for these applications use thin-gage composite facesheets (0.020" to 0.045") which are cocured to honeycomb and foam cores. Due to the nature of these structures, damage tolerance is more complex than conventional laminated structures. Besides typical damage concerns such as through penetration and delamination, additional modes including core crushing and facesheet debonding must also be addressed. This complicates the certification process by introducing undefined Allowable Damage Limits (ADL) and Critical Damage Thresholds (CDT) as related to the ultimate and limit load carrying capability of the structure. This document provides a background review of previous damage tolerance investigations including an overview of traditional metallic damage tolerance methodologies. illustrative summaries are presented which show the scope of previous investigation parameters such as impact energy, facesheet thickness, and core thickness of typical sandwich constructions. Also included is a compilation of damage tolerance certification procedures and regulations taken from FAR Part 23-29 for composite damage tolerance as well as recommendations from associated Advisory Circulars. Past and current airframe industry sandwich constructions which show the scope of current and future sandwich designs were also surveyed. In conclusion, a proposed future research approach and its methodology are presented which should aid in establishing certification guidelines and confidence involving the damage tolerance of sandwich constructions as they apply to general aviation aircraft and rotorcraft.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 1999
Accession Number
ADA367976

Entities

People

  • A. Vizzini
  • Benjamin P Smith
  • J. Tomblin
  • Sarah Hooper
  • T. Lacy

Organizations

  • Wichita State University

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Aircraft Equipment
  • Aircrafts
  • Airframes
  • Composite Materials
  • Experimental Design
  • Failure Mode And Effect Analysis
  • Fuselages
  • Laminates
  • Manufacturing
  • Material Degradation Processes
  • Materials Laboratories
  • Materials Processing
  • Materials Science
  • Materials Testing
  • Mechanical Working
  • Mechanics
  • Stress Strain Relations

Readers

  • Aviation Safety Risk Assessment.
  • Reinforced Composite Materials
  • Systems Analysis and Design