Jin-Ho Roh¹, In Lee²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.1, pp. 13-30, 2008, DOI:10.3970/cmes.2008.026.013

Abstract A methodology to maintain the configuration of inflated membrane structures using shape memory alloy (SMA) film actuator is numerically investigated. The two- dimensional incremental formulation of the SMA constitutive model is developed. New parameters related to the thermodynamic energy equation are introduced to describe more general behaviors of the SMA film. With numerical algorithm of wrinkling and SMAs, the interactions between the inflated membrane structure and the SMA film are investigated by using a finite element program. The effectiveness of SMA film to control the configuration of an inflated membrane structure is examined. To demonstrate surface configuration control, two inflatable… More >

K. Woo¹, H. Igawa², C.H. Jenkins³

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 397-408, 2004, DOI:10.3970/cmes.2004.006.397

Abstract This paper presents the development and evaluation of a wrinkling analysis procedure for anisotropic membranes. The procedure is based on a penalty-parameter modified material model and a non-linear root finding to simulate the uni-axial stress state. The procedure was implemented in the ABAQUS finite element code as a user subroutine, and then applied to annular and square membranes. The wrinkle problems were also solved by shell element post-buckling analysis and the results were compared. The effect of anisotropy and unsymmetric loading on the wrinkling behavior was investigated. More >

Ori Levin, Wei Shyy¹

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 523-536, 2001, DOI:10.3970/cmes.2001.002.523

Abstract Typical low Reynolds number airfoils suffer from reduced lift-to-drag ratio and are prone to flow separation. In order to improve the aerodynamic performance of such airfoils in an unsteady freestream, the concept of passive control is investigated. In this study, a membrane with varying thickness distribution and mechanical properties is attached on the upper surface of a modified Clark-Y airfoil and is free to move upwards and downwards in response to the pressure difference across it. The response surface method is employed to investigate the individual and collective effects of the membrane's prestress, elastic modulus, and thickness distribution on aerodynamic… More >

J.T. Katsikadelis¹, M.S. Nerantzaki¹

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 1-9, 2000, DOI:10.3970/cmes.2000.001.303

Abstract A boundary-only method is presented for the solution of the vibration problem of non-homogeneous membranes. Both free and forced vibrations are considered. The presented method is based on the Analog Equation Method (AEM). According to this method the second order partial differential equation with variable coefficients of hyperbolic type, which governs the dynamic response of the membrane, is substituted by a Poisson's equation describing a quasi-static problem for the homogeneous membrane subjected to a fictitious time dependent load. The fictitious load is established using BEM. Several numerical examples are presented which illustrate the efficiency and the accuracy of the method. More >

Leela Rakesh¹, Anja Mueller², Pratik Chhetri¹

FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 179-202, 2010, DOI:10.3970/fdmp.2010.006.179

Abstract A new material for proton conducting membrane with a higher proton transport but reduced water transport is being developed. The new material optimizes proton channel formation, this reducing water transport at the same time. Different proton transporting groups along with different gas flowing channels are examined as well. To meet the goals we design, synthesize, and simulate various proton transporting groups using MD techniques for faster optimization, which in turn helps to synthesize and test only promising structures in the laboratory. At the same time, computer modeling is used to improve the fuel cell system at various operating conditions, specifically… More >

B. Yang², V. K. Tewary³

CMC-Computers, Materials & Continua, Vol.8, No.1, pp. 23-32, 2008, DOI:10.3970/cmc.2008.008.023

Abstract A three-dimensional Green's function for a material system consisting of anisotropic and linearly elastic planar multilayers with interfacial membrane and flexural rigidities has been derived. The Stroh formalism and two-dimensional Fourier transforms are applied to derive the general solution for each homogeneous layer. The Green's function for the multilayers is then solved by imposing the surface boundary condition, the interfacial displacement continuity condition, and the interfacial traction discontinuity condition. The last condition is given by the membrane and bending equilibrium equations of the interphases modeled as Kirchhoff plates. Numerical results that demonstrate the validity and efficiency of the formulation are… More >

D. Ballhause¹, M. König¹, B. Kröplin¹

CMC-Computers, Materials & Continua, Vol.4, No.1, pp. 21-30, 2006, DOI:10.3970/cmc.2006.004.021

Abstract The mechanical behaviour of woven fabrics is dominated by the kinematics of the constituents on the microscopic scale. Their macroscopic response usually shows non-linearities which are due to the mobility of the interlaced yarns. The major deformation mechanisms of fabrics, i.e. the crimp interchange in case of biaxial tension and the trellising motion of the yarns in case of shear, reflect the dependency of the macroscopic material behaviour on the microstructural deformation mechanisms.
We present a novel modelling approach for woven fabrics which is capable to represent directly and locally the microstructure and its kinematics at yarn level. With… More >

Xiaorui Zhang^1,2,3,*, Pengpai Wang¹, Wei Sun², Norman I. Badler³

CMC-Computers, Materials & Continua, Vol.55, No.2, pp. 297-319, 2018, DOI:10.3970/cmc.2018.01764

Abstract Real-time performance and accuracy are two most challenging requirements in virtual surgery training. These difficulties limit the promotion of advanced models in virtual surgery, including many geometric and physical models. This paper proposes a physical model of virtual soft tissue, which is a twist model based on the Kriging interpolation and membrane analogy. The proposed model can quickly locate spatial position through Kriging interpolation method and accurately compute the force change on the soft tissue through membrane analogy method. The virtual surgery simulation system is built with a PHANTOM OMNI haptic interaction device to simulate the torsion of virtual stomach… More >

Junhui Meng^1,*, Mingyun Lv²

CMC-Computers, Materials & Continua, Vol.53, No.2, pp. 73-89, 2017, DOI:10.3970/cmc.2017.053.073

Abstract The study of stratospheric airships has become the focus in many countries in recent years, because of its potential applications in many fields. Lightweight and high strength envelopes are the keys to the design of stratospheric airships, as it directly determines the endurance flight performance and loading deformation characteristics of the airship. A typical envelope of any stratospheric airship is a coated-fabric material which is composed of a fiber layer and several functional membrane layers. According to composite structure, nonlinearity and viscoelasticity are the two main characteristics of such envelope. Based on the analysis on the interaction between the different… More >

Bui Duc Thuan^1,2, Wong Yonghui², Chua Kian Jon², Ng Kim Choon²

CMC-Computers, Materials & Continua, Vol.47, No.2, pp. 89-105, 2015, DOI:10.3970/cmc.2015.047.089

Abstract The cup method and dynamic moisture permeation cell (DMPC) method are two common techniques used to determine the water vapor permeation properties of a membrane. Often, ignoring the resistance of boundary air layers to the transport of water vapor results in the water vapor permeance of the membrane being underestimated in practical tests. The measurement errors are higher with highly permeable membranes. In this study, the two methods were simulated using COMSOL Multiphysics platform and the extent of the error was evaluated. Initial results showed that the error is equally high in both methods. With the correction for the still… More >