Prediction of the torsional strength of the hybrid aluminium/composite drive shaft

Analysis of a composite shaft under static torsion11OverviewIntroductionPrerequisitesFEA of hybrid aluminium/composite drive shaftFEA results and discussionComparison between the experimental and finite element resultsConclusions

2IntroductionSubstituting composite materials for conventional metals has many advantages including higher specific stiffness and strengthAdvanced composite materials seem ideal for long, power drive shaft applicationsComposites like carbon/epoxy or glass/epoxy or their hybrids successfully used as propeller shafts in aerospace applicationsApart from higher specific stiffness and strength, they also offer superior vibration damping, fatigue characteristics and corrosion resistance

33IntroductionDue to high material cost of carbon fiber/epoxy composite materials, rather inexpensive aluminium used partly composite materials as in:Hybrid aluminium/composite driveshaftAluminium: transmits the required torqueComposite: increases bending natural frequency

In this work, FEA was used to investigate maximum torsion capacity of hybrid aluminium/composite drive shaft4IntroductionMax. torsion capacity of aluminium tube wounded outside byE-glass/epoxy,carbon fiber/epoxy, andtheir Hybrids Evaluated at differentwinding anglesnumber of layers, andstacking sequences 55PrerequisitesWhat is a composite ?Why composite ?What is a lamina and laminate ? LAMINATION CODEGuidelines6

[ / / ]

[ / / ]n ------ for repeated layers

[ / / ]s ------ for symmetric laminates

A composite is a structural material that consists of two or more combined constituents that are combined at a macroscopic level and are not soluble in each other. One constituent is called the reinforcing phase and the one in which it is embedded is called the matrix. The reinforcing phase material may be in the form of fibers, particles, or flakes. The matrix phase materials are generally continuous .

Some of the advantages of using composites over conventional materials include high strength to weight ratio, high stiffness to weight ratio, high toughness, high corrosion resistance, high wear resistance, high chemical resistance and higher fatigue life.

A lamina (also called a ply or layer) is a single flat layer of unidirectional fibers or woven fibers arranged in a matrix.

A laminate is a stack of piles of composites. Each layer can be laid at various orientations and can be made up of different material systems

Guidelines for designating a laminate:The stacking of layers starts from the top of the laminateThe stacking sequence is enclosed in square brackets symbol,[ ]The distinct layers or groups of layers are separated with a slash symbol, /For repeated groups or layers, subscriptnis used to designate the number of repetitions, [ ]nThe symmetric laminate is designated by subscriptSon the square bracket, [ ]SThe total stacking sequence is designated by subscriptT, that is, by[ ]T

6PrerequisitesAn example[90/+45/-45/90]

Winding angle in case of composite tubes

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Winding angle in case of composite tubes:In case of composite tubes, winding angle is defined as the angle the strand or fiber has against an imaginary axis going in the axial direction on the outer surface of the tube.

7Finite element analysis of hybrid aluminium/composite drive shaftModeling of the specimen in ANSYS

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Configuration and dimensions of the specimen8Finite element analysis of hybrid aluminium/composite drive shaftElement type : for composite layers ---- SOLID 46 For aluminium tube ---- SOLID 45

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Finite element meshesEach layer on the hybrid shaft was modeled as a separate volume and meshed using SOLID46 element.The layered element SOLID46 allows for up to 100 different material layers with different orientations and orthotropic material properties in each layer.The element has three degrees of freedom at each node and translations in the nodal x, y, and z directions.

An eight-node solid element, SOLID45, was used for the aluminum tube.The element is defined with eight nodes having three degrees of freedom at each node translations in the nodal x, y, and z directions.

The mapping mesh technique was used for the entire domain.

9Finite element analysis of hybrid aluminium/composite drive shaftMaximum strain failure critera was used to predict failure load in this workThe failure index (I) was calculated as

Fracture is said to occur when I = 1 i.e. when the angle of twist equals the failure angle of twist 10

Finite element analysis of hybrid aluminium/composite drive shaftGlass fibersCarbon fibersCase 1[45]n[45]nCase 2[90]m[90]mCase 3[+45/-45/90/90][+45/-45/90/90]Case 4[90/+45/-45/90][90/+45/-45/90]Case 5Glass + Carbon fibers[(45)carbon/(45)glass]Glass + Carbon fibers[(45)carbon/(45)glass]11Laminates and their stacking sequencesFinite element analysis of hybrid aluminium/composite drive shaft12Material propertiesPropertiesCarbon fiberGlass fiber45904590Er(GPa)9.7895.719.0725.4E(GPa)9.789101.29.07236.6Gr(GPa)5.224.3464.3684.085r0.1260.01860.110.074The glass and carbon fiber/epoxy layers were modeled with homogenized linear elastic orthotropic materials.12Finite element analysis of hybrid aluminium/composite drive shaft13Tensile modulus, E(GPa)69Shear modulus, G(GPa)26.5Poissons ratio, m0.3Density, (kg/m3)2700Ultimate tensile stress(MPa)131Yield strength(MPa)69Shear strength(MPa)69Aluminium tubeThe elasto-plastic characteristic of aluminum tube was modeled by inputting the stressstrain relationship to ANSYS program13Finite element analysis of hybrid aluminium/composite drive shaft14

Idealized stressstrain curve for nonlinear property of the aluminum tubeThe elasto-plastic characteristic of aluminum tube was modeled by inputting the stressstrain relationship to ANSYS program14Finite element analysis of hybrid aluminium/composite drive shaft Boundary conditionsThe idea ---- subject the hybrid shaft to pure torsionOne end fixed, all DOF arrestedApply torque on the other endArrest DOF in r direction to restrict movement of nodes in radial direction

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Deformed shapeFinite element analysis results and discussionEffect of winding angle and number of layers on torsional strength16

4 layers6 layersConclusions:A hybrid shaft wound externally by carbon fiber/epoxy is stronger than the hybrid shaft wound externally by glass fiber/epoxy and supports high torque capacity .It can be seen that 45 winding angle can withstand more torque than that for 90 in case of both, glass and carbon fiber wound composite tube.As the number of layers increase, the torsional strength also increase.

16Finite element analysis results and discussionEffect of stacking sequence on torsional strength

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The torsion-failure index response is close to each other.Carbon fiber/epoxy gave higher torque capacity than that for glass fiber at same index failure

17Finite element analysis results and discussionEffect of hybridization on torsional strength18

4 layers6 layersHybridization enhanced the torque capacity of a hybrid shaft in comparison with the use of glass fiber alone on the outside of the aluminum tube.Carbon fiber/epoxy composite still gives better performance than that for hybridization.18Comparison between experimental and finite element resultsTorque versus angle of twist comparison

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[+45/+45]3 laminateThe differences are attributed to the fact that in the finite element analysis the hybrid aluminum is assumed perfect in terms of dimensions and properties.

19Comparison between experimental and finite element resultsComparion of maximum torque capaicity

20Aluminum tube wound by E-glass/epoxy composite

The differences are attributed to the fact that in the finite element analysis the hybrid aluminum is assumed perfect in terms of dimensions and properties.

20Comparison between experimental and finite element resultsComparion of maximum torque capaicity

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Aluminum tube wound by carbon fiber/epoxy compositeThe differences are attributed to the fact that in the finite element analysis the hybrid aluminum is assumed perfect in terms of dimensions and properties.

21ConclusionsAs the number of layers are increased, the static torque capacities of the hybrid shaft for both carbon and glass fiber composite materials also increases.A hybrid aluminum/composite wound with 45 layers can withstand higher static torsion compared to 90 in all cases.Shaft being laminated with stacking sequence [90/+45/-45/90] and [+45/-45/90/90] gave the same behaviour of torque-angle of twist relation.A finite element study was carried out using ANSYS software to predict the static torsion capacity including the elasto-plastic properties for aluminum tube and linear elastic for composite materials. The comparisons between the experimental and predicted results carried out using ANSYS software gave good agreement.

2222ReferencesS.A. Mutasher, Prediction of the torsional strength of the hybrid aluminum/composite drive shaft, Materials and Design 30 (2009) Page: 215220D. G. Lee , H. S. Kim, J. W. Kim, J. K. Kim, Design and manufacture of an automotive hybrid aluminum/composite drive shaft, Composite Structures 63 (2004) Page: 8799ASM Handbook, Volume 21, Composites, ASM InternationalA. K. Kaw, Mechanics of Composite Materials, Second Edition, Taylor & Francis

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