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 >

C. Wang¹, J.H. Qiu^1,2, R. Nie¹, H.L. Ji¹, W. Deng¹

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 61-80, 2012, DOI:10.3970/cmc.2012.032.061

Abstract The morphing skin has been a main obstacle in the real-world implementation of morphing aircrafts. This paper presents a morphing skin made of the elastomer reinforced by the honeycomb structure. A matrix made from elastomer provides possibilities to configure the morphing skin and the honeycomb structure with smaller in-plane modulus and larger out-of-plane modulus is thought to be suitable to reinforce the elastomer. The polyurethane elastomer is selected and synthesized by the casting method with the prepolymer approach, after which a tensile test is conducted to get its stress-strain relationship. To decrease the skin depth… More >

S.D. Akbarov^1,2

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 29-60, 2012, DOI:10.3970/cmc.2012.032.029

Abstract By the use of the Murnaghan potential the influence of third order elastic constants on axisymmetric longitudinal wave propagation velocity in a pre-stressed two-layered circular hollow cylinder is investigated. This investigation is carried out within the scope of the piecewise homogeneous body model by utilizing the first version of the small initial deformation theory of the Three-dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies. Numerical results are obtained and analyzed for the cases where the material of the outer hollow cylinder material is aluminum, but the material of the inner cylinder is steel More >

S. K. Panthi¹, Sanjeev Saxena²

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 15-28, 2012, DOI:10.3970/cmc.2012.032.015

Abstract Sheet metal forming process like deep drawing subjected to large irreversible deformation. It leads to high strain localization zones and then internal or superficial micro defects. The deformation behavior and crack initiation in cylindrical deep drawing of aluminum alloy are simulated by the elasto-plastic finite element simulation. A1100-O and A2024-T4 sheet material are used in the simulation. Material properties based on the tensile and plane strain test is used in the simulation. Six cases are simulated in this study with different blank diameter. The simulated results are compared with the experimental results in terms of More >

H.H. Luo¹, Z.H. Tan^1,2, X. Han¹, C. Chen¹

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 1-14, 2012, DOI:10.3970/cmc.2012.032.001

Abstract The dynamic properties of aluminium alloy foam were investigated by using split Hopkinson pressure bar (SHPB) with diameter of 40 mm. The aluminium alloy pressure bar and pulse shape technique were used to modify the traditional SHPB due to the low impedance of aluminium alloy foam. Wave dispersion correction on the aluminium alloy pressure bar was studied by Fourier series. And the finite element numerical simulation was also performed to demonstrate and validate the dispersion correction results by Fourier series method. The reflected and transmitted wave measured in SHPB experiments were corrected by the backward 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 >

Balamati Choudhury1¹, Sanjana Bisoyi¹, R M Jha¹

CMC-Computers, Materials & Continua, Vol.31, No.3, pp. 201-228, 2012, DOI:10.3970/cmc.2012.031.201

Abstract Soft computing methods play an important role in the design and optimization in diverse engineering disciplines including those in the electromagnetic applications. The aim of these soft computing methods is to tolerate imprecision, uncertainties, and approximations to achieve a quick solution, which is both robust and economically viable. Soft computing methods such as genetic algorithm, neural network and fuzzy logic have been widely used by researchers for microwave design since the last decade. The metamaterial multilayer concept in conjunction with transformation optics leads to exciting applications in the microwave regime with such examples as invisible More >

Cheng-Yu Ku^1,2,3, Weichung Yeih^1,2

CMC-Computers, Materials & Continua, Vol.31, No.3, pp. 173-200, 2012, DOI:10.3970/cmc.2012.031.173

Abstract In this paper, a dynamical Newton-like method with the adaptive stepsize based on the construction of a scalar homotopy function to transform a vector function of non-linear algebraic equations (NAEs) into a time-dependent scalar function by introducing a fictitious time-like variable is proposed. With the introduction of the fictitious time-like function, we derived the adaptive stepsize using the dynamics of the residual vector. Based on the proposed dynamical Newton-like method, we can also derive the dynamical Newton method (DNM) and the dynamical Jacobian-inverse free method (DJIFM) with the transformation matrix as the inverse of the… More >

M. Demiral^1,2, A. Roy¹, V. V. Silberschmidt¹

CMC-Computers, Materials & Continua, Vol.31, No.3, pp. 157-172, 2012, DOI:10.3970/cmc.2012.031.157

Abstract A comparison of a dynamic indentation method with a quasi-static one is used to study evolution of penetration and a generated force in the indentation process. Turning (a machining process) and dynamic indentation techniques are expected to have similar ranges of strain, strain rate and stress values in the process zone of a workpiece in a case of similar kinematics and boundary conditions. Here, we study the underlying mechanics of these two techniques. Based on advanced finite-element models, similarities and differences between the indentation and turning processes are elucidated.This study demonstrates that some critical cutting More >

Cherl-Hee Lee¹, Jonghun Lee¹

CMC-Computers, Materials & Continua, Vol.31, No.2, pp. 147-156, 2012, DOI:10.3970/cmc.2012.031.147

Abstract The guided modes are investigated in a five-layered slab waveguide with double claddings of metamaterials using a new graphical method. The dispersion equations in the symmetric and asymmetric five-layered slab waveguide are derived from the presented graphical method, and corresponding field distributions are plotted for the oscillating guided and surface guided modes. The energy flux distribution along the axis is plotted for the surface TE₁ mode. More >