Dielectric and mechanical studies of the durability of adhesively bonded CFRP structures subjected to aging in various solvents

Abstract

Dielectric and mechanical tests of adhesively bonded carbon fibre reinforced plastic (CFRP) joints aged in a series of solvents are reported. The solvent systems include; deicing fluids (ethylene glycol), aviation fuel, moisture, brine and paint strippers and solvents (dichloromethane and butanone). These measurements indicated that the ingress of the solvent leads to swelling of the joints and plasticization of the adhesive with consequential changes in the mechanical properties. A study of the drying process after the joints have been aged indicated that in certain cases it was possible for the mechanical properties of the joints to be recovered to almost their original values. In other cases the recovery was limited and reflected changes occurring within the adhesive layer. It was difficult to establish an unambiguous correlation between the dielectric constant of the bond and the change in the mechanical strength although in the case of water and ethylene glycol a correlation does appear to exist. The paper discusses the usefulness of the dielectric method for monitoring the ageing of CFRP adhesively bonded joints.

Keywords

CFRP structures adhesive bonding dielectric measurement durability

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References

Pethrick

R. A.

Armstrong

G. S.

Banks

W. M.

Crane

R. L.

Hayward

Dielectric and mechanical studies of the durability of adhesively bonded aluminium structures subjected to temperature cycling. Part I: Examination of moisture absorption

Proc. Instn Mech. Engrs, Part L: J. Materials: Design and Applications, 2004, 218, 169–182.

Armstrong

G. S.

Banks

W. M.

Pethrick

R. A.

Crane

R. L.

Hayward

Dielectric and mechanical studies of the durability of adhesively bonded aluminium structures subjected to temperature cycling. Part 2: Examination of the failure process and effects of drying

Proc. Instn Mech. Engrs, Part L: J. Materials: Design and Applications, 2004, 218, 183–192.

Banks

W. M.

Boinard

Pethrick

R. A.

Use of dielectric spectroscopy to assess adhesively bonded composite structures, part III: Investigation of mechanical strength

J. Adhesion, 2002, 78, 1027–1038.

Banks

W. M.

Boinard

Pethrick

R. A.

Use of dielectric spectroscopy to assess adhesively bonded composite structures, part I: Water permeation in epoxy adhesive

J. Adhesion, 2002, 78, 1001–1014.

Banks

W. M.

Boinard

Pethrick

R. A.

Use of dielectric spectroscopy to assess adhesively bonded composite structures, part II: Dielectric study

J. Adhesion, 2002, 78, 1015–1026.

Banks

W. M.

Boinard

Pethrick

R. A.

Time domain reflection dielectric spectroscopy for durability assessment of adhesively bonded composite structures

Plastics, Rubber and Composites, 2000, 29 (6), 288–293.

Halliday

S. T.

Banks

W. M.

Pethrick

R. A.

Dielectric studies of adhesively bonded CFRP/epoxy/CFRP structure — design for ageing

Composites Sci. Technol., 2000, 60 (2), 197–207.

Ivanova

K. L.

Pethrick

R. A.

Affrossman

Hygrothermal aging of rubber modified and mineral filled dicyandiamide cured digylcidyl ether of bisphenol A epoxy resin. I. Diffusion behaviour

J. Appl. Polym. Sci., 2001, 82, 3468–3476.

Ivanova

K. L.

Pethrick

R. A.

Affrossman

Investigation of hydrothermal ageing of a filled rubber toughened epoxy resin using dynamic mechanical thermal analysis and dieletric spectroscopy

Polymer, 2000, 41 (18), 6787–6796.

10.

Ivanova

K. I.

Pethrick

R. A.

Affrossman

Hygrothermal aging of rubber-modified and mineral-filled dicyandiamide-cured DGEBA epoxy resin. II. Dynamic mechanical thermal analysis

J. Appl. Polym. Sci., 2001, 82, 3477–3485.

11.

Affrossman

Banks

W. M.

Hayward

Pethrick

R. A.

Non-destructive examination of adhesively bonded structures using dielectric techniques: Review and some results

Proc. Instn Mech. Engrs, Part C: J. Mechanical Engineering Science, 2000, 214, 87–102.

12.

Z. C.

Joshi

Hayward

Gilmore

Pethrick

R. A.

High frequency electrical measurements of adhesive bonded structures — An investigation of model parallel plate waveguide structure

NDT and E Int. 1997, 30, 151.

13.

Halliday

S. T.

Banks

W.M.

Pethrick

R. A.

Dielectric studies of ageing in aluminium epoxy adhesively bonded structures: Design implications

Proc. Instn Mech. Engrs, Part L: J. Materials: Design and Applications, 1999, 213, 103.

14.

Halliday

S. T.

Banks

W. M.

Pethrick

R. A.

Dielectric studies of adhesively bonded CFRP/epoxy/CFRP structures — design for ageing

Composites Sci. Technol., 2000, 60 (2), 197–207.

15.

Halliday

S. T.

Banks

W. M.

Pethrick

R. A.

Influence of humidity on the durability of adhesively bonded aluminium composite structures

Proc. Instn Mech. Engrs, Part L: J. Materials: Design and Applications, 1999, 213, 27.

16.

ASTM D 3165–91. Standard Test Method for Strength Properties of Adhesives in Shear by Tension Loading of Single-Lap-Joint Laminated Assemblies, 1991.

17.

ASTM D 3433–93. Standard Test Method for Fracture Strength in Cleavage of Adhesives in Bonded Metal Joints, 1993.

18.

ASTM D 3807–93. Standard Test Method for Strength Properties of Adhesives in Cleavage Peel by Tension Loading (Engineering Plastics-to-Engineering Plastics), 1993.