Design and fabrication of meso-scale flexural testing apparatus for evaluating aligned CNT composite flexures

Abstract

The objective of this research is to explore the possibility of using aligned Carbon Nanotube (CNT) based composites in flexures by measuring the kinematics of a composite flexure. The first phase of the research, described in this thesis, is to design, fabricate and assemble a testing apparatus optimized for evaluating aligned CNT based composites. Using existing literature on composites and present limitations on their growth, functional requirements are set down for the testing apparatus. Several designs are qualitatively evaluated, leading to a near optimal design form. This chosen design is modeled as a spring-mass system, and the exact geometry needed to satisfy the functional requirements is determined. The design of the full apparatus is expanded to contain the necessary probes and actuators. The testing apparatus is fabricated using CNC machining, and assembled in a controlled environment to reduce thermal and mechanical error during operation. The system is calibrated and its resolution is found to be 0.021 N over a range of 28.5 N applied force and 1.5 pm over a range of 816 pm applied displacement. Several non-linearities are noted and corrected mathematically.