Title:
Micromechanical Finite element Model for Fiber Reinforced Cementitious Materials
Author(s):
Kiumars Siah, James A. Mandel, and Belal Rashid Mousa
Publication:
Materials Journal
Volume:
89
Issue:
3
Appears on pages(s):
277-288
Keywords:
fiber reinforced concretes; finite element method; microcracking; Materials Research
DOI:
10.14359/2590
Date:
5/1/1992
Abstract:
The tensile strength, toughness, and fracture toughness of cementitious materials can be significantly increased by adding small percentages of fibers by volume. The mechanical properties of the resulting composite material are dependent on the properties of its constituent materials (matrix material, fibers, and fiber-matrix interface) and the geometry of the composite (fiber volume, geometry, and spacing). A general three-dimensional micromechanical finite element model that can simulate the response to load of a typical region in a fiber reinforced material is presented. The model is a cumulative damage model in that such local failures as the formation and growth of cracks in the matrix material and/or along the fiber-matrix interface that occur prior to overall failure of the composite are accounted for. A small region in the composite with mechanical properties representative of the composite is identified. To verify experimentally the micromechanical finite element model, centrally cracked mortar tension specimens with three rows of accurately positioned steel fibers in advance of the two crack fronts were fabricated and tested. The shape of the load-displacement curve from testing of the centrally cracked specimens agrees with analytical results of the micromechanical model. Experimental values of the local maximum and minimum loads occurring just prior to and after the matrix crack growth past a row of fibers agree closely with values obtained with the micromechanical model (average deviation of 5.4 percent). Thus, the model can be useful in studies of new or existing composites.