Liang Wu¹, Xiaorui Xiang¹, Yang Chen¹, Karrech Ali^2,*, Junru Zhou^1,*, Ming Chen³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 421-443, 2019, DOI:10.32604/cmes.2019.05218

Abstract During the excavation of deep rock, a sudden change in boundary conditions will cause the in-situ stress on the excavation surface to release instantaneously. This disturbance propagates in the form of an unloading stress wave, which will enlarge the damage field of surrounding rock. In this paper, the dynamic unloading problem of the in-situ stress in deep rock excavation is studied using theoretical, numerical, and experimental methods. First, the dynamic unloading process of rock is analyzed through adopting the wave equation, and the equivalent viscous damping coefficient of the material is taken into consideration. Calculations More >

Claude Prost, Bruno Abdelnour

Sound & Vibration, Vol.52, No.2, pp. 7-10, 2018, DOI:10.32604/sv.2018.03641

Abstract Wire Rope Isolators (WRI) are well known and used for the protection of sensitive equipment against non-contact underwater explosions (UNDEX) on board Naval Ships, amongst others, which are extremely destructive and can comple`tely impair the ship’s combat capability.
Traditional WRI exhibit a number of definite advantages, such as large deflection capability, modularity and insensitivity to aggressive environment when proper materials are used. However, their inherent nonlinearity does not always provide the best solution in terms of shock attenuation. (Stiffening tension characteristics)
Fortunately, there are ways to overcome this problem, namely increasing their damping and/ or changing… More >

Mohammad Hossein Ghadiri Rad¹, Farzad Shahabian^1,2, Seyed Mahmoud Hosseini³

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.3, pp. 135-157, 2015, DOI:10.3970/cmes.2015.108.135

Abstract A meshless method based on the local Petrov-Galerkin approach is developed for elasto-dynamic analysis of geometrically nonlinear two dimensional (2D) problems in hyper-elastic functionally graded materials. The radial point interpolation method (RPIM) is utilized to build the shape functions and the Heaviside step function is used as the test function. The mechanical properties of functionally graded material are considered to continuously vary in a certain direction and are simulated using a nonlinear power function in volume fraction form. Considering the large deformations, it is assumed that the domain be made of large deformable neo-Hookean hyperelastic… More >

Priyankar Datta¹, Manas C. Ray¹

CMC-Computers, Materials & Continua, Vol.49-50, No.1, pp. 47-80, 2015, DOI:10.3970/cmc.2015.049.047

Abstract This paper deals with the implementation of the one dimensional form of the fractional order derivative constitutive relation for three dimensional analysis of active constrained layer damping (ACLD) of geometrically nonlinear laminated composite plates. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs). The von Kármán type nonlinear strain displacement relations are used to account for the geometric nonlinearity of the plates. A nonlinear smart finite element model (FEM) has been developed. Thin laminated substrate composite plates with various boundary conditions and stacking sequences are analyzed to More >

J.R. Lin¹, L.M. Chu², T.L. Chou³, L.J. Liang³, P.Y. Wang³

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.2, pp. 163-177, 2014, DOI:10.3970/fdmp.2014.010.163

Abstract We investigate the influence of non-Newtonian micropolar fluids on the dynamic characteristics of wide tapered-land slider bearings. The study is carried out on the basis of the micro-continuum theory originally developed by Eringen (1966). Analytical expressions for the linear dynamic coefficients are provided and compared with earlier results in the literature. In particular, direct comparison with the Newtonian fluid-lubricated tapered-land bearings by Lin et al. (2006) indicates that the use of non-Newtonian micropolar fluids can lead to a significant increase in the values of stiffness and damping coefficients. Such improvements are found to be even More >

Rivera MC¹, ER Wright¹, MC Fabrizio², G Freixá¹, R Cabalini¹, SE Lopez³

Phyton-International Journal of Experimental Botany, Vol.82, pp. 227-234, 2013, DOI:10.32604/phyton.2013.82.227

Abstract Damping off is a frequent disease that kills seedlings. Cultural and biological controls are the only tools in organic crops to manage this disease, and only empirical information is available on the efficiency of plant preparations. This work evaluates the effects of fermented onion decoctions on the growth of Rhizoctonia solani and Sclerotium rolfsii and disease incidence. Broth (B) and sterilized broth (SB) were respectively obtained by boiling chopped yellow onions in water, and incubating for 14 days at room temperature, with or without subsequent sterilization. The pathogens were grown on potato dextrose agar supplemented with B… More >

Chein-Shan Liu¹, Chung-Lun Kuo²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.1, pp. 57-80, 2011, DOI:10.3970/cmes.2011.077.057

Abstract In this paper, the solutions of inverse Cauchy problems for quasi-linear elliptic equations are resorted to an unusual mixed group-preserving scheme (MGPS). The bottom of a finite rectangle is imposed by overspecified boundary data, and we seek unknown data on the top side. The spring-damping regularization method (SDRM) is introduced by converting the governing equation into a new one, which includes a spring term and a damping term. The SDRM can further stabilize the inverse Cauchy problems, such that we can apply a direct numerical integration method to solve them by using the MGPS. Several More >

Chein-Shan Liu^1,2, Chung-Lun Kuo³, Dongjie Liu⁴

CMC-Computers, Materials & Continua, Vol.24, No.2, pp. 105-124, 2011, DOI:10.3970/cmc.2011.024.105

Abstract The inverse Cauchy problems for elliptic equations, such as the Laplace equation, the Poisson equation, the Helmholtz equation and the modified Helmholtz equation, defined in annular domains are investigated. The outer boundary of the annulus is imposed by overspecified boundary data, and we seek unknown data on the inner boundary through the numerical solution by a spring-damping regularization method and its Lie-group shooting method (LGSM). Several numerical examples are examined to show that the LGSM can overcome the ill-posed behavior of inverse Cauchy problem against the disturbance from random noise, and the computational cost is More >

Masato Saitoh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.3, pp. 211-238, 2010, DOI:10.3970/cmes.2010.067.211

Abstract This paper describes the transformation of impedance functions in general structural systems with non-classical damping into a one-dimensional spring-dashpot system (1DSD). A transformation procedure based on complex modal analysis is proposed, where the impedance function is transformed into a 1DSD comprising units arranged in series. Each unit is a parallel system composed of a spring, a dashpot, and a unit having a spring and a dashpot arranged in series. Three application examples are presented to verify the applicability of the proposed procedure and the accuracy of the 1DSDs. The results indicate that the 1DSDs accurately… More >

K.Willner ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.48, No.3, pp. 303-336, 2009, DOI:10.3970/cmes.2009.048.303

Abstract The dynamic behavior of structures with joints is strongly influenced by the constitutive behavior within the contact areas. In this paper the influence of an elaborate constitutive contact model based on a rough surface model is investigated. The contact model is able to describe several effects like pressure dependent contact stiffness in normal and tangential direction as well as microslip effects. The corresponding constitutive contact laws are implemented in a finite element code. Numerical simulations are compared to experimental results of a clamped double-beam experiment. More >