Failure Modes of Composite Sandwich Beams

Facing compressive failure, facing wrinkling and core shear failure are the most commonly encountered failure modes in sandwich beams with facings made of composite materials. The occurrence and sequence of these failure modes depends on the geometrical dimensions, the form of loading and type of support of the beam. In this paper the above three failure modes in sandwich beams with facings made of carbon/epoxy composites and cores made of aluminum honeycomb and two types of foam have been investigated. Two types of beams, the simply supported and the cantilever have been considered. Loading included concentrated and uniform. It was found that in beams with foam core facing wrinkling and core shear failure occur, whereas in beams with honeycomb core facing compressive failure and core shear crimping take place. Results were obtained for the dependence of failure mode on the geometry of the beam and the type of loading. The critical beam spans for failure mode transition from core shear to wrinkling failure were established. It was found that initiation of a particular failure mode depends on the properties of the facing and core materials, the geometrical configuration and loading of composite sandwich beams.

Download Full-text

Failure of Composite Sandwich Beams

Advanced Composites Letters ◽

10.1177/096369350201100301 ◽

2002 ◽

Vol 11 (3) ◽

pp. 096369350201100 ◽

Cited By ~ 6

Author(s):

I. M. Daniel ◽

E. E. Gdoutos ◽

K.-A. Wang

Keyword(s):

Failure Modes ◽

Foam Core ◽

Sandwich Beams ◽

Composite Sandwich ◽

Four Point Bending ◽

Constituent Material ◽

Closed Cell ◽

Failure Envelopes ◽

Geometrical Dimensions ◽

Cell Foam

A thorough investigation of failure behaviour of composite sandwich beams under three- and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterised and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared with analytical predictions. The initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical dimensions.

Download Full-text

Core Failure Modes in Composite Sandwich Beams

10.1115/imece2001/ad-23776 ◽

2001 ◽

Author(s):

Isaac M. Daniel ◽

Emmanuel E. Gdoutos ◽

Jandro L. Abot ◽

Kuang-An Wang

Keyword(s):

Failure Modes ◽

Sandwich Beams ◽

Deformation And Failure ◽

Balsa Wood ◽

Composite Sandwich ◽

The Core ◽

Aluminum Honeycomb ◽

Failure Loads ◽

Materials Failure ◽

Core Materials

Abstract Core failure modes were studied in composite sandwich beams under three-point bending and in cantilever beams under end loading. The beams consisted of unidirectional carbon/epoxy face sheets and a variety of core materials, including aluminum honeycomb, PVC closed-cell foams, polyurethane foam and balsa wood. The constituent materials were fully characterized and in the case of the core materials, failure envelopes were developed for biaxial states of stress. Deformation and failure mechanisms were studied experimentally by means of moiré gratings and birefringent coatings. Results were obtained for stress (strain) distributions in the linear and nonlinear/plastic range of the core, critical failure loads and their dependence on geometrical dimensions, material parameters and loading conditions.

Download Full-text

Bending Response of Composite Sandwich Beams with M-Type Folded Cores

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1049-1050.452 ◽

2014 ◽

Vol 1049-1050 ◽

pp. 452-455

Author(s):

Li Xin Cong ◽

Yu Guo Sun

Keyword(s):

Failure Modes ◽

Fiber Composite ◽

Sandwich Beam ◽

Deformation Mode ◽

Sandwich Beams ◽

The Finite Element Method ◽

Carbon Fiber Composite ◽

Maximum Displacement ◽

Three Point Bending ◽

Composite Sandwich

Bending properties and failure modes of sandwich structure with carbon fiber composite M-type folded cores were investigated and presented in this paper. Three point bending responses of both sandwich beams were measured. The finite element method was utilized to determine deformation mode of sandwich beam with M-type folded cores. Cores buckling and debonding have been studied under three point bending and the maximum displacement was also studied using FE-analytical and experimental methods.

Download Full-text

Failure modes of composite sandwich beams

Theoretical and Applied Mechanics ◽

10.2298/tam0803105g ◽

2008 ◽

Vol 35 (1-3) ◽

pp. 105-118 ◽

Cited By ~ 22

Author(s):

E. Gdoutos ◽

I.M. Daniel

Keyword(s):

Failure Modes ◽

Failure Behavior ◽

Foam Core ◽

Sandwich Beams ◽

Composite Sandwich ◽

Four Point Bending ◽

Constituent Material ◽

Closed Cell ◽

Failure Envelopes ◽

Geometrical Dimensions

A thorough investigation of failure behavior of composite sandwich beams under three-and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterized and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared with analytical predictions. The initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical dimensions.

Download Full-text