A. T. Rhead¹, T. J. Dodwell¹, R. Butler^1,2

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 1-16, 2013, DOI:10.3970/cmc.2013.035.001

Abstract When (robotic) Automated Fibre Placement (AFP) is used to manufacture aerospace components with complex three dimensional geometries, gaps between fibre tows can occur. This paper explores the interaction under compressive load of these tow gaps with impact damage. Two coupons with different distributions of tow-gaps were impacted. Results indicated that the area of delamination is smaller for an impact directly over a tow gap where the tow gap is situated close to the non-impact face. Subsequent Compression After Impact (CAI) testing demonstrated that both the formation of sublaminate buckles and subsequent growth of delaminations is More >

A. Ataş¹, C. Soutis²

CMC-Computers, Materials & Continua, Vol.34, No.3, pp. 199-226, 2013, DOI:10.3970/cmc.2013.034.199

Abstract A strength prediction method is presented for double-lap single fastener bolted joints of cross-ply carbon fibre reinforced plastic (CFRP) composite laminates using cohesive zone elements (CZEs). Three-dimensional finite element models were developed and CZEs were inserted into subcritical damage planes identified from X-ray radiographs. The method makes a compromise between the experimental correlation factors (dependant on lay-up, stacking sequence and joint geometry) and three material properties (fracture energy, interlaminar strength and nonlinear shear stress-strain response). Strength of the joints was determined from the predicted load-displacement curves considering sub-laminate and plylevel scaling effects. The predictions are More >

Xue-Qian Fang^1,2, Ming-Juan Huang¹, Jun-Ying Wu³, Guo-Quan Nie¹, Jin-Xi Liu¹

CMC-Computers, Materials & Continua, Vol.33, No.2, pp. 199-211, 2013, DOI:10.3970/cmc.2013.033.199

Abstract In nanocomposites, coated nano-fibers are often used to obtain good performance, and the high interface-to-volume ratio shows great effect on the macroscopic effective properties of nanocomposites. In this study, the effect of interface energy around the unidirectional coated nanofibers on the effective dynamic effective properties is explicitly addressed by effective medium method and wave function expansion method. The multiple scattering resulting from the series coating nano-fibers is reduced to the problem of one typical nano-fiber in the effective medium. The dynamic effective shear modulus is obtained on the basis of the derived imperfect interface conditions. More >

G. Meneghetti¹

Structural Durability & Health Monitoring, Vol.8, No.2, pp. 111-130, 2012, DOI:10.3970/sdhm.2012.008.111

Abstract This paper deals with the local approach based on the Notch Stress Intensity Factors (NSIFs) to analyse the fatigue behavior of welded joints. In transverse load carrying fillet-welded joints, failure may occur either at the toe or at the root, depending on the geometry. At the toe, due to the flank angles that are usually encountered in practice, mode I local stresses are singular, while mode II stresses are not. Conversely, at the root of the particular joints analysed in the present paper both mode I and mode II stresses are singular and must be… More >

M. Pankow¹, A.M. Waas², C.F. Yen³

CMC-Computers, Materials & Continua, Vol.32, No.2, pp. 81-106, 2012, DOI:10.3970/cmc.2012.032.081

Abstract The compression response of 3D woven textile composites (3DWC) that consist of glass fiber tows and a polymer matrix material is studied using a combination of experiments and finite element based analyses. A previous study reported by the authors consisted of an experimental investigation of 3DWC under high strain rate loading, Pankow, Salvi, Waas, Yen, and Ghiorse (2011). Those experimental results were explained by using the finite element method to analyze the high rate deformation response of representative volume elements (RVEs) of the 3DWC, Pankow, Waas, Yen, and Ghiorse (2012). In this paper, the same More >

A. Ramachandra Murthy¹, Nagesh R. Iyer¹, B.K. Raghu Prasad²

CMC-Computers, Materials & Continua, Vol.31, No.3, pp. 229-252, 2012, DOI:10.3970/cmc.2012.031.229

Abstract This paper presents the advanced analytical methodologies such as Double- G and Double - K models for fracture analysis of concrete specimens made up of high strength concrete (HSC, HSC1) and ultra high strength concrete. Brief details about characterization and experimentation of HSC, HSC1 and UHSC have been provided. Double-G model is based on energy concept and couples the Griffith's brittle fracture theory with the bridging softening property of concrete. The double-K fracture model is based on stress intensity factor approach. Various fracture parameters such as cohesive fracture toughness (K_Ic^c), unstable fracture toughness (K_Ic^un) and… More >

A. Ramachandra Murthy¹, Nagesh R. Iyer¹, B.K. Raghu Prasad²

CMC-Computers, Materials & Continua, Vol.30, No.2, pp. 177-194, 2012, DOI:10.3970/cmc.2012.030.177

Abstract This paper presents the details of nonlinear finite element analysis (FEA) of three point bending specimens made up of high strength concrete (HSC, HSC1) and ultra high strength concrete (UHSC). Brief details about characterization and experimentation of HSC, HSC1 and UHSC have been provided. Cracking strength criterion has been used for simulation of crack propagation by conducting nonlinear FEA. The description about FEA using crack strength criterion has been outlined. Bi-linear tension softening relation has been used for modeling the cohesive stresses ahead of the crack tip. Numerical studies have been carried out on fracture More >

Raghvendra Khedle¹, D.P.Mondal², S.N.Verma¹, Sanjay Panthi²

CMC-Computers, Materials & Continua, Vol.27, No.3, pp. 211-230, 2012, DOI:10.3970/cmc.2011.027.211

Abstract The interface in aluminum cenosphere syntactic foam (ACSF) is modeled using FEM to study its deformation behaviour as a function of interface characteristics such as interface stiffness and thickness. The interface is modeled as a thin layer of object. The effective modulus and stress of ACSF examined when it contain 50% cenosphere by volume. In this study, the shell wall thickness of cenosphere is fixed at 1µm. The width of the interface varies from 0.2% to 0.6% of cenosphere volume fraction. The interface strength and modulus varies in the range of 10 to 50% of the More >

Smitha Gopinath^1,2, A. Ramachandra Murthy¹, Bhaskar Srivastava¹, V. Ramesh kumar¹, Nagesh R. Iyer¹

CMC-Computers, Materials & Continua, Vol.27, No.1, pp. 73-100, 2012, DOI:10.3970/cmc.2012.027.073

Abstract The present study investigates the behavior of concrete specimens confined with woven roving glass fabrics under uniaxial compression. The fabric made up of 360G.S.M. woven roved E-glass is embedded in a polyester resin before application. Experimental investigations have been carried out on confined and unconfined concrete specimens of size 150 mm (diameter) X 300 mm (height) under a displacement controlled loading. The effect of number of layers on confinement has also been investigated. Load versus deflection plots have been obtained for all the specimens. Numerical studies have been performed on the confinement effect of the… More >

A. Ramachandra Murthy¹, Nagesh R. Iyer¹, B.K. Raghu Prasad²

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.6, pp. 459-480, 2012, DOI:10.3970/cmes.2012.089.459

Abstract This paper presents the details of crack growth study and remaining life assessment of concrete specimens made up of high strength concrete (HSC, HSC1) and ultra high strength concrete (UHSC). Flexural fatigue tests have been conducted on HSC, HSC1 and UHSC beams under constant amplitude loading with a stress ratio of 0.2. It is observed from the studies that (i) the failure patterns of HSC1 and UHSC beams indicate their ductility as the member was intact till the crack propagated up to 90% of the beam depth and (ii) the remaining life decreases with increase… More >