skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Damage progression in mechanically fastened composite structural joints

Abstract

Progressive damage and fracture of a bolted graphite/epoxy composite laminate is evaluated via computational simulation. The objective of this paper is to demonstrate a new methodology that scales up constituent material properties, stress and strain limits to the structure level to evaluate the overall damage and fracture propagation for mechanically fastened composite structures. An integrated computer code is used for the simulation of structural degradation under loading. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulation. Results show the damage progression sequence and structural fracture resistance during different degradation stages. The effect of fastener spacing is investigated with regard to the structural durability of a bolted joint.

Authors:
 [1]; ;  [2]
  1. Clarkson Univ., Potsdam, NY (United States). Dept. of Civil and Environmental Engineering
  2. NASA-Lewis Research Center, Cleveland, OH (United States). Structures Div.
Publication Date:
OSTI Identifier:
89796
Report Number(s):
CONF-9409291-
ISBN 1-56676-220-0; TRN: IM9536%%226
Resource Type:
Conference
Resource Relation:
Conference: 9. technical conference of the American Society for Composites, Newark, DE (United States), 20-22 Sep 1994; Other Information: PBD: 1994; Related Information: Is Part Of Proceedings of the American Society for Composites: Ninth technical conference; PB: 1319 p.
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; COMPOSITE MATERIALS; BOLTED JOINTS; FRACTURE PROPERTIES; CARBON FIBERS; EPOXIDES; COMPUTERIZED SIMULATION; CRACK PROPAGATION; MATHEMATICAL MODELS; FINITE ELEMENT METHOD; MECHANICAL PROPERTIES; PHYSICAL PROPERTIES; TENSILE PROPERTIES

Citation Formats

Minnetyan, L., Chamis, C.C., and Murthy, P.L.N. Damage progression in mechanically fastened composite structural joints. United States: N. p., 1994. Web.
Minnetyan, L., Chamis, C.C., & Murthy, P.L.N. Damage progression in mechanically fastened composite structural joints. United States.
Minnetyan, L., Chamis, C.C., and Murthy, P.L.N. 1994. "Damage progression in mechanically fastened composite structural joints". United States. doi:.
@article{osti_89796,
title = {Damage progression in mechanically fastened composite structural joints},
author = {Minnetyan, L. and Chamis, C.C. and Murthy, P.L.N.},
abstractNote = {Progressive damage and fracture of a bolted graphite/epoxy composite laminate is evaluated via computational simulation. The objective of this paper is to demonstrate a new methodology that scales up constituent material properties, stress and strain limits to the structure level to evaluate the overall damage and fracture propagation for mechanically fastened composite structures. An integrated computer code is used for the simulation of structural degradation under loading. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulation. Results show the damage progression sequence and structural fracture resistance during different degradation stages. The effect of fastener spacing is investigated with regard to the structural durability of a bolted joint.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month =
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • The present conference considers advanced fastener technology for composite and metallic joints, a fatigue life-enhancing and high interference bushing installation employing the 'ForceMate' technique, fatigue life improvement by cold working fastener holes in 7050 aluminum alloy, the fatigue strength of bolted and adhesively bonded structural steel joints, and the effect of load transfer on the fatigue of mechanically fastened metallic joints. Also discussed are the evaluation of a stochastic initial fatigue quality model for fastener holes, the experimental characterization of cracks at open holes and in rounded-end straight attachment lugs, the fatigue of riveted metallic joints, an enhanced stop-drill repairmore » procedure for cracked structures, the influence of fastener flexibility on load transfer and fatigue life prediction in multiple row joints, the strength and lifetime of bolted laminates, and the fatigue of bolted continuous-fiber/sheet-molding-compound composite-metal joints.« less
  • This book presents the papers given at a conference on the fatigue of metals and composite materials. Topics considered at the conference included advanced fastener technology for composite and metallic joints, cold working, the experimental characterization of cracks, fastener flexibility, and the enhanced stop-drill repair procedure for cracked structures.
  • Because of their high strength-to-weight and stiffness-to-weight ratios, carbon fiber reinforced plastic (CFRP) composite laminates are seeing increasing use, especially in the aerospace industry. In composite-to-metal structures the load transfer between various components is undertaken by the use of mechanically fastened or bonded joints. For example, on the F/A-18 aircraft, numerous composite-to-metal mechanically fastened joints are used to transfer loads from the thick composite wing skin to the metal wing ribs and spars. Previous work, undertaken at ARL, has investigated the fatigue of such joints under ambient conditions. It is widely known that the mechanical properties of CFRP laminates generallymore » degrade considerably under hot/wet environments. A similar degradation is expected for mechanically fastened laminates. The aim of this study was to investigate the effects of hot/wet environments on the fatigue behavior of specific mechanically fastened joints. Results showed a marked decrease in the fatigue life of the composite-to-metal mechanically fastened joints under hot/wet environments when compared to lives attained at ambient and under similar load conditions. The major joint failure mode was failure of the fasteners. Other failure modes were compression failure of the 0{degree} ply layers and delamination growth.« less
  • In this study, mechanical behavior and designing method for multiple-joints were examined. Three joint forms, which were single-hole joints, two-holes in parallel and two-holes in series, were chosen. As a result, the behavior of the multiple-joints was different with that of single-holed joints. Especially, joints that exhibited bearing failure in single-hole joints appeared net-tension failure in two-holes in series. So it is cleared that designing using the data of single-hole is very dangerous since bearing failure appears safety fracture propagation and high strength but net-tension failure appears risky fracture propagation and low strength. So it is necessary to examine themore » design method that considers the stress distribution of multiple-joints. The proposed strength prediction method using a numerical analysis was applied to multiple-joints. It is cleared that the real jointed structures can be designed by the proposed method since good agreement was obtained between experimental and predicted joint strength.« less
  • The extensive use of lightweight advanced composite materials in unmanned aerial vehicles (UAVs) drastically increases the sensitivity to both fatigue- and impact-induced damage of their critical structural components (e.g., wings and tail stabilizers) during service life. The spar-to-skin adhesive joints are considered one of the most fatigue sensitive subcomponents of a lightweight UAV composite wing with damage progressively evolving from the wing root. This paper presents a comprehensive probabilistic methodology for predicting the remaining service life of adhesively-bonded joints in laminated composite structural components of UAVs. Non-destructive evaluation techniques and Bayesian inference are used to (i) assess the current statemore » of damage of the system and, (ii) update the probability distribution of the damage extent at various locations. A probabilistic model for future loads and a mechanics-based damage model are then used to stochastically propagate damage through the joint. Combined local (e.g., exceedance of a critical damage size) and global (e.g.. flutter instability) failure criteria are finally used to compute the probability of component failure at future times. The applicability and the partial validation of the proposed methodology are then briefly discussed by analyzing the debonding propagation, along a pre-defined adhesive interface, in a simply supported laminated composite beam with solid rectangular cross section, subjected to a concentrated load applied at mid-span. A specially developed Eliler-Bernoulli beam finite element with interlaminar slip along the damageable interface is used in combination with a cohesive zone model to study the fatigue-induced degradation in the adhesive material. The preliminary numerical results presented are promising for the future validation of the methodology.« less