Non-Linear Stress-Strain Effects in the Flexural Wrinkling of Carbon Fibre Honeycomb Sandwich Beams

1982 ◽  
Vol 33 (1) ◽  
pp. 1-24 ◽  
Author(s):  
A.K. Ditcher ◽  
J.P.H. Webber
Keyword(s):  
Carbon Fibre ◽  
Sandwich Beam ◽  
Sandwich Beams ◽  
Stress Strain ◽  
Tangent Moduli ◽  
Honeycomb Sandwich ◽  
Non Linear ◽  
Theoretical Predictions ◽  
Failure Loads ◽  
Carbon Fibre Reinforced Plastic

SummaryA theoretical analysis of the flexural wrinkling of a honeycomb sandwich beam with laminated faces having non-linear stress-strain behaviour is presented. Appropriate tangent moduli are used in the constitutive equations for the compression face and a double iteration technique is used to calculate wrinkling loads. Numerical results are given for sandwich beams with unidirectional and cross-ply carbon fibre reinforced plastic (CFRP) faces. Experimental failure loads of sandwich beams are compared with theoretical predictions, and, in general, the agreement between the two is good.

Non-linear stress-strain behaviour of carbon fibre reinforced plastic laminates

1981 ◽  
Vol 16 (1) ◽  
pp. 43-51 ◽  
Author(s):  
A K Ditcher ◽  
F E Rhodes ◽  
J P H Webber
Keyword(s):  
Thermal Effects ◽  
Curing Temperature ◽  
Stress Strain ◽  
Plane Shear ◽  
Reinforced Plastic ◽  
Strain Behaviour ◽  
Non Linear ◽  
Theoretical Predictions ◽  
Linear Behaviour ◽  
Carbon Fibre Reinforced Plastic

An analytical method is proposed which predicts the non-linear stress-strain response of a CFRP laminate. The method uses a secant modulus iterative method and includes thermal effects due to the temperature difference of a laminate from its curing temperature. Details of the basic CFRP non-linear behaviour in transverse and in-plane shear loadings are given. Experimental data on 0°/±45°/0° balanced laminates are presented and compared with theoretical predictions.

The effect of elevated temperature on the mechanical properties and failure modes of GFRP face sheets and PET foam cored sandwich beams

2018 ◽  
Vol 22 (4) ◽  
pp. 1235-1255
Author(s):  
Mohsen Rezaei ◽  
Vasileios Karatzas ◽  
Christian Berggreen ◽  
Leif A Carlsson
Keyword(s):  
Compressive Strength ◽  
Polyethylene Terephthalate ◽  
Failure Modes ◽  
Shear Failure ◽  
Elevated Temperatures ◽  
Sandwich Beam ◽  
Standard Test ◽  
Sandwich Beams ◽  
The Face ◽  
Failure Loads

The influence of elevated temperatures on stiffness and strength of composite face sheet and polyethylene terephthalate foam cored sandwich beam has been experimentally investigated. Standard test methods and analytical failure models were used to determine the effect of elevated temperatures. The authors examined E-glass/epoxy cross-ply face laminates, polyethylene terephthalate foam, and sandwich beams consisting of glass/epoxy face laminates and polyethylene terephthalate foam core loaded in four-point flexure. The tensile properties of the face laminate were examined over a temperature range from 25 to 175°C. Compression and shear tests on the face laminate, polyethylene terephthalate foam, and sandwich beams were performed at temperatures up to 100°C. The face laminates exhibited moderate reductions of Young’s modulus and tensile strength, while the compressive strength, shear modulus, and shear strength substantially decreased at elevated temperatures. Similarly, the compressive and shear moduli as well as the compressive strength of the polyethylene terephthalate foam decreased substantially by exposure to a temperature of 100°C. The failure mode of the sandwich panels was observed to be highly dependent on temperature, distinguishing three basic failure modes, viz. core shear failure, indentation failure, and face wrinkling. The failure loads associated to these failure modes were calculated using models available in the literature. The failure loads were found to be consistent with the failure predictions and failure modes.

Experimental Buckling Loads of Sandwich Panels with Carbon Fibre Faceplates

1973 ◽  
Vol 24 (4) ◽  
pp. 295-312 ◽  
Author(s):  
T R A Pearce ◽  
J P H Webber
Keyword(s):  
Carbon Fibre ◽  
Constitutive Equations ◽  
Sandwich Panels ◽  
Buckling Loads ◽  
Reinforced Plastic ◽  
Theoretical Predictions ◽  
Coupling Terms ◽  
Honeycomb Cores ◽  
Carbon Fibre Reinforced Plastic ◽  
Overall Buckling

SummaryExperiments to determine the overall buckling and faceplate wrinkling loads of sandwich panels with carbon fibre reinforced plastic faces and honeycomb cores when loaded under uniaxial compression are described. The results are compared with theoretical predictions which assume that the faceplates are orthotropic. The effect on the experimental loads of certain coupling terms, which occur in the constitutive equations of those faceplates which are not orthotropic, is then considered.

A method for the production of carpet plots for notched compression strength of carbon fibre reinforced plastic multidirectional laminates

1997 ◽  
Vol 211 (4) ◽  
pp. 251-261 ◽  
Author(s):  
C Soutis ◽  
E C Edge
Keyword(s):  
Carbon Fibre ◽  
Compression Strength ◽  
Room Temperature ◽  
Prediction Method ◽  
Cfrp Laminates ◽  
Reinforced Plastic ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Open Hole ◽  
Carbon Fibre Reinforced Plastic

This paper outlines a newly developed method for the calculation of the notched compression strength of carbon fibre reinforced plastic (CFRP) laminates. The BAe-Warton laminate strength prediction method (1) is used to predict the unnotched strength of the laminate and the Soutis et al. model (2) to predict the notch effect. Notched and unnotched strengths are reported for a wide range of T800/924C and T800/5245C carbon fibre—epoxy multidirectional laminates with 0°, ±45° and/or 90° lay-ups; results are compared with theoretical predictions and in most cases the error is less than 10 per cent. Carpet plots of open hole compression strength for different T800/5245C lay-ups tested at room temperature (RT)/dry and 100°C/wet are produced. Finally, the open hole strengths generated by the Soutis et al. (2) model are factored by using appropriate experimental data to allow for plain and countersunk filled holes.

Fatigue performance of undamaged and repaired composite sandwich beams

2003 ◽  
Vol 217 (3) ◽  
pp. 229-248
Author(s):  
S Mahdi ◽  
A J Kinloch ◽  
F L Matthews ◽  
M A Crisfield
Keyword(s):  
Low Temperature ◽  
Carbon Fibre ◽  
Fatigue Performance ◽  
Sandwich Beams ◽  
Composite Sandwich ◽  
Four Point Bending ◽  
Reinforced Plastic ◽  
Tension And Compression ◽  
Carbon Fibre Reinforced Plastic ◽  
Low Temperature Cure

The behaviour of undamaged (i.e. as-manufactured) and repaired carbon fibre reinforced plastic (CFRP) sandwich beams loaded in cyclic four-point bending is described. Three repair configurations (one overlap and two scarf) were tested in tension and compression, and two repair systems (high- and low-temperature cure) were employed. The repaired beams always showed an inferior performance compared with the as-manufactured beams. The lifetime was dependent on the repair configuration, with the overlap repairs performing surprisingly well when loaded in compression. The degradation of stiffness with cycling was also investigated and was related to the microscopic evolution of damage.

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