7/7/2014 1:30:00 AM
NEWS BRIEFS
FAJRI Examining Bolt-Tightening Technology in Automotive Manufacturing
Sayed Nassar
MEDIA SPOTLIGHT – The Fastening & Joining Research Institute is working on a federally-funded initiative focusing on the challenges of joining lightweight materials, such as aluminum, magnesium and carbon-fiber composites. Researchers are assessing different joining methods in terms of the environmental condition effects on heat, humidity, static, dynamic load transfer capacity and joint durability.
FAJRI is located at Oakland University’s School of Engineering – minutes away from Chrysler’s corporate headquarters in the Detroit suburb of Auburn Hills, MI, Assembly magazine pointed out.
Another recent project examined how to adapt highly repeatable aerospace bolt-tightening technology to automotive manufacturing, Assembly reported. “The real-time ultrasonic process uses high-frequency sound waves to estimate the amount of force a bolt provides to clamp two components together. Several hundred measurements per second permit feedback control to achieve consistent clamp force.”
“We pursue fundamental and applied research to develop and disseminate new technologies for the fastening and joining of metals, composites and polymers,” Sayed Nassar, Ph.D. told reporter Austin Weber of Assembly.
Nassar, a mechanical engineering professor and director of FAJRI, said the objective is to enhance the reliability and safety of joints by advancing the science and technology of mechanical fastening, adhesive bonding, welding and riveting.
“Applications include automotive and aerospace bolted assemblies, adhesively bonded joints, and welded joints,” Nassar told Assembly. “Special focus is assigned to multi-material lightweight applications for weight reduction and energy saving. [We also study] medical devices, such as [ways to stabilize] damaged human joints after spine, neck, knee or hip injuries.”
FAJRI was created in 2003 through Congressional funding with the assignment of “finding ways to meet increased demand for the reliability and combat readiness of military vehicles, with trickle down civilian benefits in the automotive, energy and transportation sectors,” Nassar said.
Twenty faculty and students are currently involved in FAJRI projects, which focus on developing advanced technologies that apply to threaded fasteners in bolted assemblies made of metals, composites, plastics and advanced polymers; adhesive bonding of laminated and fiber-reinforced composites; resistance welding of metals; and advanced riveting.
“Analytical, experimental and computer simulation techniques are used in the research,” Nassar told Assembly. “[For assembly line applications], we simultaneously consider the following [conditions] that are responsible for overall reliability and safety: Joint variables, such as materials, design, gaskets, tolerances, finish and heat treatment; fastener variables, such as coating, plating and manufacturing method; and assembly tool variables, such as type, capability, accuracy and repeatability.”
Other factors include process controls, such as torque-only, torque-angle, torque-to-yield, bolt stretch and elastic interaction; post-assembly loads, such as fatigue, service loads, gasket creep relaxation and vibration loosening; and environmental variables, such as corrosion, chemical, thermal and humidity.
Another FAJRI project has been safety issues due to joint leakage at nuclear power plants.
FAJRI has worked with Chrysler, Cummins, Daimler, Deere, General Electric and the U.S. Army Tank Automotive Research & Development Engineering Center.
FAJRI is located at 248 Dodge Hall of Engineering, Oakland University, 2200 N. Squirrel Rd. Rochester, MI 48309-4401. Tel: 248 370-3781 Web: oakland.edu/secs/fajri
Editor’s Note: Articles in Media Spotlight are excerpts from publications or broadcasts which show the industry what the public is reading or hearing about fasteners and fastener companies.
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