No abstract

The crack geometry effect is encountered in compliance matrix as a tensor containing 17 on-plane stress/strain component interrelation. The components of compliance matrix vary due to the effects of the directional fabric behavior of the material created by inherent/induced anisotropy that can be differed in any of the multi-direction through material. Mathematically, any alterations in multidirectional material behavior are numerically integrated and affected in material compliance matrix. The main objective of this paper is to develop a numerical approach to determine the crack initiation and its growth for brittle materials such as concrete. Upon the numerical integration technique, any multi-directional behavior aspect is affected by components of compliance matrix to reflect historically in the next step material behavior. Accordingly, the proposed model results are investigated to satisfy both equilibrium and compatibility equations. In this paper, previous selected 13 sampling points in numerical integration are updated to 17 planes to overcome the compatibility problem. To show the capability of the model, a few fractured concrete test results under different loading stress/strain paths were examined. The significant advantage of the proposed multi-laminate model is to present a complete pre-failure history of stress/strain progress on different predefined sampling planes which leads to the illustration of the final damaged or failure mechanism. K E Y W O R D S anisotropy, complete compliance matrix, concrete, damage, multi-laminate

A parametric study approach evaluating drained/undrained behavior of sand has been developed as a simple/quick hypo-elastic model capable of being used in engineering applications. The volumetric interaction of sand grains behavior against pore water pressure induces the tendency of soil mass volume change to contract/dilate due to variation of effective mean stress on solid grain, pore water pressure by compressibility and shear induced dilation/compression which lead to an ideal condition for constant total volume of undrained test. However, any individual volume changes of named components may result in a partial reduction of the effective mean stress to an extent that can be disclosed as a local decrease in stress deviator. In the extreme case, the effective stress components may become so small (or even zero) resulting in complete loss of strength and cause the soil to flow in a manner resembling a liquid known as liquefaction of sand. However, in real case, any possibility of water dissipation or volumetric change tendency of components can change the state/condition to activate some shear strength by increasing the effective mean stress. The proposed parametric study approach is able to present such volumetric variation condition leading to partial or complete liquefaction condition. This model has predicted and verified several compression triaxial test results of sands. The verification of model is presented by comparing the obtained results with the experimental result of Nevada sand, in both drained and undrained conditions. The proposed model can be successfully used for other soils behavior by using the proposed parametric study method including the required parameters to achieve acceptable results.