| Author | Nirmalendran, Sivalingam |
| Call Number | AIT Thesis no.ST-90-18 |
| Subject(s) | Fracture mechanics
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Abstract | Microcracking and bridging are major mechanisms in fracture of quasi-brittle
materials such as concrete, rock and ceramics. An analytical model of fracture process
zone which includes both microcracking and bridging is developed to estimate the effects
of microcracking and bridging. While the material property on bridging is represented
by the tension-softening curve, which is the inelastic component of post-peak behavior
in tension test, that on microcracking is related to the pre-peak nonlinear behavior.
Relationship between microcrack density and the stress level is determined from pre-peak
stress-strain curve in uniaxial tension test. The material parameters on microcracking
are identified through a microcracking law which relates the orientation and the density
of microcracks to the state of stress at the point in question. The dominant microcracking
parameter is found through the model. With the given material properties on bridging
and microcracking, the model predicts the shape and size of the microcracking zone,
the distribution of microcrack density and the length of bridging zone at each load level.
Results of the present model are compared with those of the model which includes only
bridging. It is shown that the increase in toughness due to microcracking varies for
different materials but remain_s small portion of the total toughness for real materials.
For the case that bridging is dominant, Dugdale-Barenblatt-type model, which includes
bridging zone only, serves as a good model of fracture phenomena and provides reasonable
estimate of, for example, the maximum load of structures. |
| Year | 1990 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Horii, Hideyuki |
| Examination Committee(s) | Karasudhi, Pisidhi ;Worsak Kanok-Nukulchai
|
| Scholarship Donor(s) | The Government of Australia. |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1990 |