Thesis
Mechanical behavior of micromechanical devices
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/102955
Abstract
This research focuses on the fracture behavior of highly boron6doped silicon for the production of a blast6wave "fuse" style sensor. The development of this sensor aims to detect blast6wave overpressure magnitudes in order to determine the amount of damage that personnel may experience from proximity to an explosion. The development and implementation of this sensor started with a rectangular wet6etched (100) boron6doped silicon sample that consisted of 165 mm side length square diaphragms each increasing in size by 1 mm. After burst testing determined that 365 mm square diaphragms fractured in the range of 506500 kPa, which lies in the range of eardrum rupture, lung damage, and 1% potential lethality, it was determined to be the most likely candidate pressure range for the sensor. The fracture toughness of this material was determined with nanoindentation with a cube6corner tip in an array of single indents of loads ranging from 1mN610mN by measuring the cracks of each indent in scanning probe images. The resulting toughness was 0.61 MPa6m1 / 2 for pure silicon and 0.58 MPa6m1/2 for boron6doped silicon. Finite element models were used to design a packaging system for the fuse sensors, and further FEA analysis determined that the rectangular sample geometry was unsuitable for the sensor. These tests determined that our hypothesis of the larger membrane fracturing v at lower pressures and with decreasing size, increasing pressure is needed to fracture to be false for the rectangular geometry due to stress concentrations on the edges. Due to this, a new geometry is proposed for a next generation of sensor and package.
Metrics
7 File views/ downloads
16 Record Views
Details
- Title
- Mechanical behavior of micromechanical devices
- Creators
- Jessica Leann Parsons
- Contributors
- David F. Bahr (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525392301842
- Language
- English
- Resource Type
- Thesis