No abstract

In this research, an investigation was carried out through experimentation and numerical modeling to evaluate the cracking pressure induced due to corrosion of reinforcement for different cover thicknesses, grades of concrete and bar locations. The model was also used to determine the patterns of crack for a different number of bars and the effect of bar diameter on cracking pressure. The critical pressure was measured experimentally by applying hydraulic pressure through a hole in concrete cubes of 150 mm. Abaqus 6.14 was used as a modeling platform. From the experimentation and numerical modeling, it was found that with the increase of cover thickness the critical pressure was increased irrespective of bar locations. A lower cracking pressure was observed for corner bar with respect to the sidebar. On the other hand, with the increase in bar diameter, a decrease in cracking pressure was observed. The critical pressure observed was also increased with higher grades of concrete. For corner bars with cover thickness 37.5 mm, the critical pressure was found as 6-10 MPa and it increased up to 17 MPa for the cover thickness of 64 mm for different grades of concrete. On the other hand, for other bar location with the cover thickness of 37.5 mm and 64 mm, the pressure required to initiate crack was about 7.6 MPa and 14.8 MPa, respectively, for C20 grade concrete.

In this paper, a delamination growth analysis on composite panel containing embedded delamination has been performed using a three-dimensional finite element model. The effects of the delamination on the local buckling load and delamination growth are studied by using Hashin’s 3D failure criteria via UMAT user’s subroutine of ABAQUS FE program. A new proposed model shows enhancement of the accuracy of the results which showed a good agreement with available experimental data.

This paper aims at developing the numerical of delamination in laminated composite structures. Formation of initial delamination and growth of existing delamination in HAT-Section laminated made of plies of unidirectional carbon fiber reinforced epoxy resin is investigated computationally. Tsai-Hill failure method is employed to predict delamination initiation while delamination propagation is analyzed using linear elastic fracture mechanics (LEFM).The techniques based on LEFM that have been utilized successfully within the framework of the finite element method (FEM) for the simulation of delamination growth, the virtual crack closer technique (VCCT). Finally this paper proposes future work for precise prediction of delamination of unidirectional carbon fiber reinforced epoxy resin HAT-Section specimens.

This paper presents an improved rail shear method of ASTM D 4255/D4255M and the design procedure of new fixture for low cyclic shear loading. This fixture is designated to determine mechanical properties of in-plane shear modulus, nonlinear shear stress-strain curves, shear strength and visco-elastoplastic behaviour of fibrous composites under cyclic shear loads. A series of experiments have been carried out using the new rig to determine shear stress-strain response of unidirectional fibre reinforced laminated specimens under various cyclic loading conditions. An FE simulation has been conducted using a commercial code ABAQUS and its user subroutine UMAT to define nonlinear material behaviour as a verification of the accuracy of the new Cyclic Rail Shear Fixture (CRSF).