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Abstract iitk


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Abstract iitk

  1. 1. STRESS ANALYSIS OF BASALT /EPOXY LAMINATE J.Alexander1, DR.BSM.Augustine2 1 ,PhD Scholar, Sathyabama University,Chennai-600119 e-mail 2 Professor,Sathyabama University,Chennai-600119 IntroductionBASALT FIBER, A new kind of inorganic fiber like glass fiber, isfabricated from basalt rocks through the melting process. It has ahigher working temperature and better tensile strength than E-glassfiber as well as good resistance to chemical attack, impact load, andfire with less poisonous fumes. In addition, the basalt fibers do notneed any other additives in the single producing process, addingspecial benefit in cost. Basalt fiber reinforced composites show greatimprovement in the elastic modulus, chemical resistance and thermalstability compared to glass fiber reinforced composites. Theseadvantages make basalt fiber a promising alternative to glass fiber asa reinforcement material in aerospace, metallurgical, chemical,building industries and so on. In the past five years the use of basaltfibers have been tried in many applications and close attention hasbeen paid to its qualities, especially the excellent chemical resistancewhich accelerates the application of basalt fibers in both organic andinorganic matrix composites. At this work Basalt epoxy laminate wasfabricated using hand lay up process and the material properties werefound using experimental methods. Classical Laminated theory isused for calculating Lamina stresses which are compared with laminastresses of various composite materials.The result shows baslt/epoxylaminate has very good strengths at axial loads.
  2. 2. The basalt fiber used in the experiment was Basalt fabric whosedensity is2.7grams/cm3 mixed with LY552 epoxy resins .The fiber –resin volume fraction is 60:40 After being impregnated in resins andcured, the basalt yarns were cut short to about 350 mm, and smoothand rounded specimens were selected for the tests of tensile strength,tensile modulus and elongation at break. Both ends of the selectedsamples were tabbed by two pieces of starched paper to avoid the endbreakage caused by test machine clamp. The gauge length of thesample was 200 mm. The basalt yarns tensile strength was tested on auniversal testing machine according to GB3362-82, and the loadvelocity was 2 mm/min. Table i Tensile Test Results Width(mm Thickness(mm) Breaking Tensile Tensile ) load(N) strength modulus (N/mm^2) (KN/mm^2) 26.4 4.3 16.8 148 12.247 25.8 4.65 15.38 128 11.822 24.8 4.8 17.1 144 10.952 Table ii Compression test Results Area (mm^2) Breaking load(N) Compression strength (N/mm^2) 12.25*12.65 30.96 200 13.5*13.75 24.8 134 13.5*13.25 29.06 163 The above Test result are used in the laminated plate theory for stressanalysis II Laminated Plate TheoryThe mechanics of materials deal with stresses, strains, anddeformations in engineering structures subjected to mechanical andthermal loads. A common assumption in the mechanics ofconventional materials, such as steel and aluminum, is that they are
  3. 3. homogeneous and isotropic continua. For a homogeneous material,properties do not depend on the location, and for an isotropicmaterial, properties do not depend on the orientation. Unless severelycold-worked, grains in metallic materials are randomly oriented sothat, on a statistical basis, the assumption of isotropy can be justified.Fiber-reinforced composites, on the other hand, are microscopicallyinhomogeneous and non isotropic (orthotropic). As a result, themechanics of fiber-reinforced composites. Lamination theory isuseful in calculating stresses and strains in each lamina of a thinlaminated structure. Beginning with the stiffness matrix of eachlamina, the step- by-step procedure in lamination theory includes1. Calculation of stiffness matrices for the laminate2. Calculation of mid plane strains and curvatures for the laminatedue to a given set of applied forces and moment s3. Calculation of in-plane strains εxx, εyy , and γxy for each lamina4. Calculation of in-plane stresses sxx, syy , and txy in each laminaThe geometric midplane of the laminate contains the xy axes, and the z axisdefines the thickness direction. The total thickness of the laminate is h, andthe thickness of various laminas are represented by t1, t2, t3, and so on. Thetotal number of laminas is N. A sketch for the laminate is shown inFigure 1
  4. 4. ---------------------------------------------------------------------------------------------------------------(1)whereε0xx -, ε0yy mid plane normal strains in the laminate 0γ xy - mid plane shear strain in the laminatekxx ,- k yy bending curvatures of the laminatekxy - twisting curvature of the laminatez - distance from the mid plane in the thickness directionLaminate Forces and Moments
  5. 5. Applied force an d moment resultant (Figure 2) on a laminate arerelated to the mid plane strains and curvatures by the followingequations-----------------------------------(2) FIGURE 2 In-plane, bending, andtwisting loads applied on a laminate.In matrix notion the force and moment equations are written as -------------------------------------------------------------------------(3) -----------------------------------------------------------------------------(4)
  6. 6. -----------------------------------------------------------------------------------------(5)------------------------------------------------------------------------------------------(6)--------------------------------------------------------------------------------------------(7)The fabricated Basalt/epoxy laminate is subjected to an axial load of100N in the X direction and the stresses in each ply is analysed byusing matlab software .***************************************************************** * Analysis of Composite Laminates Based on* * Classical Laminated Plate Theory * ****************************************************************************** Material 4: User Material: BASALT/EPOXY552 Engineering Properties ********************** Matl E1 E2 G12 v12 1 1.810e+011 1.028e+010 7.172e+009 0.280 2 3.931e+010 8.552e+009 3.724e+009 0.280 3 8.690e+010 5.517e+009 2.138e+009 0.340 4 5.480e+010 1.757e+010 7.138e+009 0.232 Stacking Sequence ***************** Layer Matl Ply Angle Ply Thickness 1 4 30.0 1.200e+000 2 4 60.0 1.200e+000
  7. 7. 3 4 30.0 1.200e+000 ---------- Laminate Mechanical Input Load Vector ************************************* NX NY NXY MX MYMXY 1.000e+002 0.000e+000 0.000e+000 0.000e+000 0.000e+0000.000e+000 Laminate Matrices ***************** ABD Matrix 1.191e+011 3.977e+010 3.431e+010 7.629e-006 5.722e-0063.815e-006 3.977e+010 9.636e+010 2.475e+010 5.722e-006 1.144e-0052.861e-006 3.431e+010 2.475e+010 5.053e+010 3.815e-006 2.861e-0067.629e-006 7.629e-006 5.722e-006 3.815e-006 1.504e+011 4.295e+0104.623e+010 5.722e-006 1.144e-005 2.861e-006 4.295e+010 8.224e+0101.755e+010 3.815e-006 2.861e-006 7.629e-006 4.623e+010 1.755e+0105.458e+010 Apparent Laminate Stiffness Properties ************************************** EX EY GXY EXBEYB 2.487e+010 2.187e+010 1.070e+010 2.597e+010 1.788e+010 Apparent Laminate Coupling Coefficients (Poisson and Shear Coupling) *************************************** vXY vYX nXY,X nXY,Y nX,XY nY,XY 0.273 0.240 -0.545 -0.327 -0.235 -0. Laminate Total Strain Vector **************************** eX eY gXY KX KY KXY 1.117e-009 -3.046e-010 -6.091e-010 -4.898e-026 -2.501e-0276.534e-026 Stresses and Strains in the Global Coordinate System (X,Y) - LowerSurfaces **************************************************************************** Layer Eps-X Eps-Y Gam-XY Sig-X Sig-YSig-XY 1 1.117e-009 -3.046e-010 -6.091e-010 3.321e+001 3.540e+0003.775e+000 2 1.117e-009 -3.046e-010 -6.091e-010 1.691e+001 -7.081e+000-7.549e+000 3 1.117e-009 -3.046e-010 -6.091e-010 3.321e+001 3.540e+0003.775e+000 Stresses and Strains in the Material Coordinate System (1,2) - LowerSurfaces Strains are given as Total Strains (Mechanical + Thermal +Moisture)
  8. 8. ******************************************************* ********************** Layer Eps-1 Eps-2 Gam-12 Sig-1 Sig-2 Sig-12 1 4.978e-010 3.146e-010 -1.536e-009 2.906e+001 7.689e+000 -1.096e+001 2 -2.129e-010 1.025e-009 -9.265e-010 -7.621e+000 1.745e+001 -6.613e+000 3 4.978e-010 3.146e-010 -1.536e-009 2.906e+001 7.689e+000 -1.096e+001 Material Strengths ****************** Matl Xt Xc Yt Yc S 1 1.500e+009 -1.500e+009 4.000e+007 -2.462e+008 6.828e+007 2 1.083e+009 -6.207e+008 3.931e+007 -1.283e+008 8.897e+007 3 1.276e+009 -3.379e+008 2.897e+007 -1.579e+008 4.897e+007 4 1.480e+008 -2.000e+008 1.480e+008 -2.000e+008 1.400e+007 Conclusion For a particular load the stresses in each layer is calculated .These stress values are compared with results of same type of laminate with different material. But the properties of basalt /epoxy laminate is better than Glass/epoxy laminate. Hence glass/epoxy can be replaced by Basalt/epoxy for various structural applications. (Detailed results will be discussed in the full paper. References 1. Medvedyev, O. O. and Tsybulya, Y. L. (2004). The Outlook for the use of Basalt Continuous Fibers for Composite Reinforcement[C], International SAMPE Technical Conference, SAMPE 2004, 16–20 May 2004, Long Beach, CA, United States, pp. 275–279. The effect of adhesion interaction on the mechanical properties of 2. thermoplastic basalt plastics P. I. Bashtannik, A. I. Kabak,and Yu. Yakovchuk, Mechanics of Composite Materials, Vol. 39, No. 1, 2003. 3 Novel basalt fibre reinforced glass matrix composites, e. bernardo e. stoll†,, a. r. boccaccini j mater sci 41 (2006) 1207–1211.       4. Chemical Composition and Mechanical Properties of Basalt and Glass Fibers:A Comparison Tamás Deák and Tibor Czigány,Textile Research Journal 2009 79: 645.
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