1,721,206 research outputs found
Natural frequencies of angle-ply laminated plates
No full textDynamic analysis of laminated rectangular simply-supported plates with antisimmetric lamination is performed. The accuracy of existing theories for the estimate of natural frequency is investigated. The 3D elasticity solution is obtained and used as a benchmark solution for four different plate theories: CLT, FSDT , HSDT [1] and the 2D-theory recently proposed by the second Author
Assessment of plate theories for multilayered angle-ply plates
No full textThe accuracy of laminated plate theories for the analysis of angle-ply multilayered plates is investigated. Classical Lamination Theory, First Order and Reddy’s High Order Shear Deformation Theories are considered, together with a new two-dimensional theory recently proposed by the second Author (2D-theory). Deflections and through-the-thickness stress distributions are compared with the exact 3D elasticity solution. Energy errors of stress fields obtained from the various theories through both constitutive and equilibrium equations are also evaluated. It is shown that equilibrium equations are required to obtain sufficiently accurate stress distributions from CLT, FSDT and HSDT, whereas stresses can be obtained directly from constitutive equations for the 2D-theory
Monofilament technical textiles: an analytical model for the prediction of the mechanical behaviour
No full textThe work presents an analytical model to evaluate the mechanical behaviour of dry monofilament
technical textiles. The mechanical behaviour is obtained by a three-dimensional
analytical model based on a theory of curved beam. Taking into consideration a unit cell,
the macroscopic (or global) behaviour of the monofilament textile is investigated assuming
the nonlinear constitutive behaviour of the fibres obtained by experimental tests. The comparison
between the predicted analytical mechanical responses and the experimental test
results is detailed
Shakedown analysis of unidirectional fiber reinforced metal matrix composites
No full textIn this paper the determination of the shakedown domain in the space of macroscopic stresses of ductile unidirectional composite materials is obtained solving a shakedown analysis problems defined over a Representative Volume. The analyses are based on the kinematic shakedown theorem and the assumption of plane strain condition. The mathematical programming problem generated is solved by an iterative procedure. Numerical tests are performed on Al/Al2O3 metal matrix composite and compared to the relevant macroscopic plastic collapse domains
Plane strain shakedown analysis of unidirectional fiber reinforced metal matrix composites
No full textIn this paper the determination of the shakedown domain in the space of macroscopic stresses of unidirectional fibre reinforced metal matrix composites is obtained solving a shakedown
analysis problem defined over a Representative Volume (). The analyses are based on the kinematic shakedown theorem and the assumption of plane strain state. The mathematical programming problem generated is solved by an iterative procedure
On the mechanical behaviour of monofilament technical textiles
No full textIn this work the mechanical behaviour of dry monofilament technical textiles is investigated. The considered textiles are typically used in the screen printing industry. In this and other fields, the
deformability of the textile is an essential aspect for the quality of the final product. Therefore, a full knowledge of the mechanical properties of the textile is mandatory to predict the influence of several aspects. The mechanical behaviour of the monofilament textiles is here studied by means of numerical analyses of different representative volume (RV) geometries. Two different monofilament polyester plain-weave textiles were examined. For both textiles, the three-dimensional finite element models of two RVs were produced. The validation of the proposed numerical approach was conducted comparing the numerical results to the experimental observations for the two textiles during different loading conditions
Multi-scale mechanical numerical analysis of multi-axial composites
No full textIn this paper an overview of a numerical approach to evaluate the mechanical behaviour until failure of multi-axial composites and the validation of the method against experiments is presented. The
procedure is a multi-scale modelling technique essentially based on the solution of nested boundary value problems, one for each scale. The main assumption at each scale is the periodic distribution
of the reinforcements to apply the homogenization theory for periodic media. The modelling is implemented in a two-scale computational homogenization procedure to study the mechanical behaviour of textile composites and multi-layer stitched composites. The experimental data on a glass textile plain weave composite and a
multi-axial multi-ply carbon stitched laminate are compared to the results of the numerical analyses
ASSESSMENT OF THE FATIGUE LIFE OF 3D TEXTILE REINFORCED COMPOSITES
No full textThe broad range of applications of 3D textile reinforced composites requires an in-depth knowledge of their mechanical properties. Among those, the fatigue behaviour receives high demand in several industrial applications. In this paper an overview of some experimental investigations is summarized to assess the influence of the three-dimensional architecture of the preform on the fatigue properties and damage evolution. The considered composite materials were produced using epoxy resins reinforced with: non-crimp 3D orthogonal weave E-glass fabric; 3D braided carbon fabric; structurally stitched carbon multi-ply preform. The tensile-tensile fatigue response was investigated in the principal directions for several load levels to get a complete understanding of the influence of the 3D reinforcements on the fatigue life. Damage initiation and development during cyclic loading were investigated by means different techniques
Biaxial tensile behaviour of composite reinforcements
No full textThe deformability of a composite reinforcement depends mainly on its internal structure and has a relevant influence on the quality of a composite component. Among the mechanical features of a composite reinforcement, the biaxial behavior plays an important role on its capability to drape a complex shape. This chapter details some of the methodologies employed to measure and to predict the tensile biaxial behavior of textile composite reinforcements. The features of some experimental biaxial loading devices are described, as well as some experimental results. A predictive analytical model for plain weave reinforcements is briefly described and compared to experimental data. Finally, the main characteristics of numerical models dedicated to meso-scale simulations, based on the finite element method, are highlighted
Two-scale modeling for failure analysis of textile composites
No full textA two-scale homogenization technique is presented to evaluate the mechanical properties of woven textile composites. The numerical approach is founded on the main assumption of periodic distribution of the reinforcements in the composite at two different scale. The first scale concerns the warp and weft yarns while the second regards a representative volume of the woven textile laminate with homogenized yarns. The main aim is to predict the macroscopic behavior until failure of textile composites. The procedure is validated against experimental results
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