This Small Business Innovation Research (SBIR) Phase I project will develop real-time ultrasonic control of the tightening of bolted assemblies, using a varying, stress-dependent, wave speed algorithm. Existing technology uses ultrasonic measurement to verify the fastener tensile force by measuring its elongations after it has been tightened and disregards the wave varying speed, included in our control algorithm. The project will determine the sound wave speed and the stress level correlation in solids, developing an algorithm to vary the wave speed according to fastener elongation, integrating the ultrasonic device and the new algorithm into the assembly tool, and assessing the validity of the tabulated stress factor in ultrasonic measurements. The broader impacts resulting from this project will be improvement in the transportation safety of passenger cars and trucks, it is seen that his could help the U.S. economy and local economy by increasing productivity through reduced downtime and warranty costs associated with failed machines and products. Significant benefits to many industries, the aerospace, transportation systems, nuclear and fossil power generation plants as well as the automotive industry
