Files and links (1)
Madhukar_Madhu_198518.95 MB
PDF Restricted Access, VIEWABLE UPON REQUEST: contact archives@drexel.edu
Dissertation
Fracture behavior of boron/aluminum laminates at room and elevated temperatures
Doctor of Philosophy (Ph.D.), Drexel University
1985
DOI:
https://doi.org/10.17918/00009104
Abstract
This thesis presents the results of a detailed and comprehensive research work, both experimental and analytical, on the deformation characteristics and fracture behavior of boron/aluminum composites at room and elevated temperatures. Emphasis has been placed on subjects associated with the load-deformation curves of center-notched laminates, including the elastic region, damage initiation, damage progression, notched strength, notch sensitivity, and failure mechanisms and processes. A variety of nondestructive and destructive experimental techniques are employed: the interferometric displacement gage to obtain the precise crack opening displacement; acoustic emission to monitor damage initiation and progression and determine the failure mechanisms and processes in real-time; and the conventional techniques to characterize the mechanical behavior of a material. Analytically, predictions of deformation characteristics and notch sensitivity are made. Existing models of fracture behavior in composites are reviewed in sufficient detail and predictions based on these models are compared with experiments. Special attention has been given on analyzing the deformation characteristics of unidirectional center-notched boron/aluminum. A new model is developed which incorporates the matrix nonlinearity. A detailed parametric analysis has been performed on this new model to determine the effect of numerous variables (e.g. matrix properties, fiber diameter, volume fraction, crack length and test temperature) on the stress concentration factors, inelastic zone length, crack opening displacement, damage initiation, and notch sensitivity. A very good agreement is obtained between the predictions of the proposed model and experiments. In this study the proper test methodology for new composite systems has been established. The applicability of a variety of analytical procedures to metal-matrix composites has been critically evaluated, and a comprehensive data base on the deformation characteristics of boron/aluminum composites is established. The results of this research also provide future directions for the study of MMC as well as offering improved criteria for tailoring material properties to meet the specific design requirements.
Metrics
10 Record Views
Details
- Title
- Fracture behavior of boron/aluminum laminates at room and elevated temperatures
- Creators
- Madhu S. Madhukar
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Science (1970-1990); Drexel University
- Other Identifier
- 991021889009904721