Measurements for Materials

Systems (2001-2004)

MMS11

Design for Fatigue and Creep in Joined Systems

30 April 2003

Project outline

Evaluation of design methods for predicting deformation and failure bolted and adhesively bonded joints

MonotonicCreepFatigue

Development and evaluation of models for describing deformation and failure of

Tough adhesivesFibre-reinforced laminates

Determination of model parameters for different materialsComparison of predictions with measurements using a selected joint geometry

300 mm

15 mm

150 mm

101.6 mm

15 mmAdhesive thickness = 0.5 mm

15 mm

35 mm 50 mm

15 mm 15 mm

web

base plate

flange

All parameter changes were based on this starting geometry

Geometry of bonded study jointGeometry of bonded study joint

Bonding optionsBonding options

Filled “Bermuda Triangle” Unfilled “Bermuda Triangle”(basic geometry)

MaterialsMaterials

Rubber Toughened Epoxy AdhesivesXD4601 (Dow Chemicals) and DP460 (3M)

Adherends2014 aluminium alloyGRP – UD + biaxial woven fabric/epoxy (SP Systems)

Surface TreatmentAluminium - chromic acid etchedComposite - grit blasted

SystemsAluminium/XD4601 and GRP/DP460

Autoclave Moulding GRP FlangesAutoclave Moulding GRP Flanges

Problems: Autoclave curing + spring-back

Evaluation of models for tough adhesives

Monotonic loadingElastic-plastic models

Von MisesLinear Drucker-PragerExponent Drucker-PragerCavitation

Application described in a Smart ManualCreep loading

Model based on non-linear creep in plasticsApplication to FE analysis

CB

A

Deformed Mesh Superimposed on Original MeshDeformed Mesh Superimposed on Original MeshTransverse TensionTransverse Tension

Contour Plot of SContour Plot of S1111 Stress at Predicted Failure LoadStress at Predicted Failure Load(contours are shown for the adhesive region only)(contours are shown for the adhesive region only)

Full 3Full 3--D ModelD ModelMeshMesh DiscretisationDiscretisation, Applied Load and Supports, Applied Load and Supports

½ mesh – direct tension full mesh - transverse and 45° tension(sufficient) (necessary)

C B

A

Experimental ArrangementExperimental Arrangement

Publications and reports

Geometric and Material Property Effects on the Performance of

Adhesive T-Joints, NPL Measurement Note MATC(MN)29.

Geometric and Bolt Position Effects on the Performance of Bolted

T-Joints, NPL Measurement Note MATC(MN)30.

Finite Element Assessment of Geometric and Material Property

Effects on the Strength and Stiffness of Bonded and Bolted Joints,

NPL Report MATC(A)124.

Prediction of Deformation and Failure of Rubber-toughened

Adhesive Joints submitted to Int. J. Adhesion and Adhesives

Smart Manual

Deformation and Failure of Rubber-Toughened Adhesive Joints

Recent publications and reportsRecent publications and reports