A. A. Abdulrazeg¹, J. Noorzaei^1,2, P. Khanehzaei¹, M. S. Jaafar¹, T. A. Mohammed¹

CMES-Computer Modeling in Engineering & Sciences, Vol.68, No.3, pp. 239-268, 2010, DOI:10.3970/cmes.2010.068.239

Abstract Development of temperature rise in massive concrete structure such as a roller compacted concrete dam is attributed to hydration of concrete and environmental boundary conditions. These thermal changes in the material affect the elastic, creep properties of the material, and in turn, the stress fields within the structure. Therefore, the effects of temperature on the properties of RCC materials( elastic, creep) has to be taken into account in order to determine the risk of the thermally induced cracking in these dams. In the present work an attempt has been made to consider the effect of temperature on the elastic and… More >

Qiang Tong¹, Qingwen Ren^{1, *}, Lei Shen ², Linfei Zhang ², Yin Yang³

CMES-Computer Modeling in Engineering & Sciences, Vol.114, No.1, pp. 33-58, 2018, DOI:10.3970/cmes.2018.114.033

Abstract In this article, the post-peak softening stage of the constitutive relation and the elastic stiffness degradation of concrete are investigated, and a highly reasonable constitutive relation curve is proposed. At the material level, the energy change in the concrete failure process is studied based on the different stress-strain curves of concrete under uniaxial tension and compression. The concrete failure criterion based on elastic strain energy density is deemed suitable and consistent with the experimental phenomena. The hysteresis phenomenon (lags behind the peak strength) is also discussed. At the structure level, the strength reduction method is employed for the stability analysis,… More >

Min Hwan Oh, Hee Jun Lee, Minho Chung, Jin Yeon Cho, Do Soon Hwang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.3, pp. 93-94, 2011, DOI:10.3970/icces.2011.020.093

Abstract Lunar lander may experience various impact loadings when it makes a landing on the lunar surface. Due to the reason, shock absorption system of lunar lander should be designed to absorb the landing energy of lunar lander efficiently for a successful lunar mission. Shock absorption system should be reliable, and the entire landing energy should be absorbed into the shock absorption system to prevent a critical bouncing or turn-over. One the other hand, to protect the payloads, excessive deceleration should be avoided while absorbing the landing energy.

To design an efficient shock absorption system of lunar lander, which satisfies… More >

Su Ji-Jun^1,2, Zhang Zhao-Cheng¹, Hu Hong¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.11, No.4, pp. 87-94, 2009, DOI:10.3970/icces.2009.011.087

Abstract This paper concentrates on the development and evaluation of linear characteristics of a complex flexure hinge with high accuracy and large stiffness. The flexure hinge mechanism is used to clamp the shaft of a micropositioning stage based on the inchworm principle. Six key parameters of the flexure hinge are optimized by using finite element method. Developed flexure hinge has very good effects on the clamping and resilience that are accurate and reasonable. The evaluation result shows that the flexure hinge has excellent linear characteristic. More >

Xingbin Chen¹, Qingchun Hu^1,*, Zhongyang Xu¹, Yao Ding², Qianli Mai¹, Chune Zhu³

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 447-470, 2019, DOI:10.31614/cmes.2019.04330

Abstract The multistage face gears are the core component of the planetary gear train, which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical gears. However, it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number differences. Thus, the interference problems between two stages and big stress concentration are obvious. The crown surface configuration technology and structure design were introduced to optimize the meshing condition. To improve the double crown design feasibility and meshing stability, it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various… More >

Marco Götz^1,*, Ferenc Leichsenring¹, Thomas Kropp², Peter Müller², Tobias Falk², Wolfgang Graf¹, Michael Kaliske¹, Welf-Guntram Drossel²

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.3, pp. 387-423, 2018, DOI:10.31614/cmes.2018.04112

Abstract Numerical mechanical models used for design of structures and processes are very complex and high-dimensionally parametrised. The understanding of the model characteristics is of interest for engineering tasks and subsequently for an efficient design. Multiple analysis methods are known and available to gain insight into existing models. In this contribution, selected methods from various fields are applied to a real world mechanical engineering example of a currently developed clinching process. The selection of introduced methods comprises techniques of machine learning and data mining, in which the utilization is aiming at a decreased numerical effort. The methods of choice are basically… More >

Xuwen An^1,2, Jianguo Hou³, P.D. Gosling⁴, Dong Dai⁵, Long Xiao⁶, Xiaoyi Zhou⁷

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.1, pp. 1-25, 2015, DOI:10.3970/cmes.2015.107.001

Abstract Studies on the theory of structural system reliability includes identification of main the failure modes and calculation of inclusive failure probabilities for the structural system. The efficient and accurate identification of failure modes in structural systems is difficult and represents a key focus for research in system reliability. The fundamental theory of the branch and bound algorithm for stage critical strength is reviewed in this paper. Some deficiencies in this method are highlighted. Corresponding approaches to overcome these deficiencies are proposed. Calculated system reliability solutions to the classical model, a truss with 10 elements, indicate that the improvement measures proposed… More >

Zhengzheng Cao¹, Yuejin Zhou^1,2, Ping Xu¹, Jiawei Li¹

CMES-Computer Modeling in Engineering & Sciences, Vol.101, No.5, pp. 351-364, 2014, DOI:10.3970/cmes.2014.101.351

Abstract In accordance with the influence of underground mining on the deformation and failure of a shallow-buried gas pipeline, the pipe-soil interaction during mining is classified into two stages, namely coordinated deformation stage and partial hanging stage. According to the mechanical characteristics of the buried pipeline in each stage, the models of a) a beam on an elastic foundation, b) an elastic beam under uniform load, and c) a vertical and horizontal bending beam are introduced in a mining subsidence zone to mechanically analyze, respectively a) the pipeline in non-mining subsidence zone, b) the pipeline at the coordinated deformation stage, and… More >

Jun-Sheng Duan^1,2, Randolph Rach³, Abdul-Majid Wazwaz⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.1, pp. 77-118, 2013, DOI:10.3970/cmes.2013.094.077

Abstract In this paper, we propose a new modification of the Adomian decomposition method for solution of higher-order nonlinear initial value problems with variable system coefficients and solutions of systems of coupled nonlinear initial value problems. We consider various algorithms for the Adomian decomposition series and the series of Adomian polynomials to calculate the solutions of canonical first- and second-order nonlinear initial value problems in order to derive a systematic algorithm for the general case of higher-order nonlinear initial value problems and systems of coupled higher-order nonlinear initial value problems. Our new modified recursion scheme is designed to decelerate the Adomian… More >

Weichung Yeih^1,2, Chein-Shan Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.2, pp. 107-128, 2009, DOI:10.3970/cmes.2009.046.107

Abstract We consider an inverse problem for estimating an unknown time dependent heat source H(t) in a heat conduction equation u_t(x,t) = u_xx(x,t) + H(t). First this inverse problem is formulated as a three-point boundary value problem (BVP) for ODEs discretized from the transformed homogeneous governing equation. To treat this three-point BVP we develop a two-stage Lie-group shooting method (TSLGSM). The novel approach is examined through numerical examples to convince that it is rather accurate and efficient; the estimation error is small even for identifying discontinuous and oscillatory heat sources under noise. More >