Home / Journals / CMC / Vol.3, No.2, 2006
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  • Open Access

    ARTICLE

    A New Method of Controlling Shrinkage Cracking in Repaired Concrete Structures Using an Interface Layer of Carbon Fiber Reinforced Cement Mortar

    Shen Yubin1, Xie Huicai1,2, Den Wei1
    CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 49-54, 2006, DOI:10.3970/cmc.2006.003.049
    Abstract Bonding an overlay of new concrete onto the damaged concrete is a usual repair method. Because of the different shrinkage rate of the new and old concrete, restrained shrinkage cracks will appear in the new concrete. The cracks will reduce durability and strength of the repaired structure. A new repair method using an interface layer of carbon fiber reinforced cement mortar between new and old concrete was developed in this paper. The new method was found to be very effective in reducing shrinkage cracking of repaired beams and slabs. Comparing with normal repaired beams, the maximum observed width of the… More >

  • Open Access

    ARTICLE

    An Optimization Analysis of UBM Thicknesses and Solder Geometry on A Wafer Level Chip Scale Package Using Robust Methods

    Heng-Cheng Lin1, Chieh Kung2, Rong-Sheng Chen1, Gin-Tiao Liang1
    CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 55-64, 2006, DOI:10.3970/cmc.2006.003.055
    Abstract Wafer level chip scale package (WLCSP) has been recognized providing clear advantages over traditional wire-bond package in relaxing the need of underfill while offering high density of I/O interconnects. Without the underfill, the solder joint reliability becomes more critical. Adding to the reliability concerns is the safety demand trend toward "green'' products on which unleaded material, e.g. lead-free solders, is required. The requirement of lead-free solders on the packages results in a higher reflow temperature profile in the package manufacturing process, in turn, complicating the reliability issue. This paper presents an optimization study, considering the fatigue reliability, for a wafer… More >

  • Open Access

    ARTICLE

    Analysis of Solids with Numerous Microcracks Using the Fast Multipole DBEM

    P. B. Wang1, Z. H. Yao1,2, T. Lei1
    CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 65-76, 2006, DOI:10.3970/cmc.2006.003.065
    Abstract The fast multipole method (FMM) is applied to the dual boundary element method (DBEM) for the analysis of finite solids with large numbers of microcracks. The application of FMM significantly enhances the run-time and memory storage efficiency. Combining multipole expansions with local expansions, computational complexity and memory requirement are both reduced to O(N), where N is the number of DOFs (degrees of freedom). This numerical scheme is used to compute the effective in-plane bulk modulus of 2D solids with thousands of randomly distributed microcracks. The results prove that the IDD method, the differential method, and the method proposed by Feng… More >

  • Open Access

    ARTICLE

    Object-Oriented Modeling of Solid Material in Nonlinear Applications

    Hamid Sharifi1 and Augustin Gakwaya1
    CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 77-96, 2006, DOI:10.3970/cmc.2006.003.077
    Abstract In this paper, an object-oriented modeling of solid material constitutive behavior using the UML notation is presented. Material properties are first classified into large and small deformation kinematical models. In the small deformation package, we keep classes such as Elastic, ElastoPlastic, ViscoElastic and ViscoPlastic. In the large deformation package, we store classes such as ElastoPlastic, HyperElastic, HyperPlastic, HyperViscoElastic, HyperViscoPlastic and so on. The hierarchical structure, the association relationships as well as key attributes and methods of these classes are presented. We used a C++ implementation of the above model for developing HyperElastic, HyperElastoPlastic and Contact applications in the Diffpack environment. More >

  • Open Access

    ARTICLE

    An Equation for Stress Concentration Factor in Countersunk Holes

    Kunigal N. Shivakumar1, Anil Bhargava1, Sameer Hamoush2
    CMC-Computers, Materials & Continua, Vol.3, No.2, pp. 97-106, 2006, DOI:10.3970/cmc.2006.003.097
    Abstract A detailed three-dimensional finite element stress analysis was conducted on straight-shank and countersunk rivet holes in a plate subjected to tension loading. The study included a wide range of plate width to radius, thickness to radius, countersunk depth to thickness ratios and countersunk angles(θc). The stress concentration is maximum at or near the countersunk edge. The stress concentration depends on countersunk depth, plate thickness and width and it is nearly independent of the countersunk angle for 80° ≤ θc ≤ 120°. Using the finite element results and limiting conditions, an equation for stress concentration factor is developed and verified. More >

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