The Physics of Vibratory Stress Relief

Abstract Submittal

Trends in Welding Research 2012

Authors:

Dr. C. Mel Adams

1606 Ridout Rd

Annapolis, MD 21401-5537

Cell 443.254.1632

Bruce Klauba

VSR Systems & Service

2007 Pennsylvania Avenue

Croydon, PA  19021

Cell 215.901.5742

Title of paper:          The Physics of Vibratory Stress Relief

Abstract:

The physics of vibratory stress relief is examined.  High-resolution spectra of vibration amplitude and vibrator input power vs. vibration excitation frequency illustrate the modifications resonance peaks undergo during stress relief.  Different nodal patterns representing different modes of resonant vibration and resulting flexure patterns are depicted in photos.

Of special interest to researchers of vibratory stress relief for decades is identification of the physical property or properties of the work-piece being stress relieved that change during the changes in resonance pattern, and how they change (both magnitude and direction).   Among the physical properties examined are the structure's rigidity and dampening.

An example of the vibratory operating system and data are shown in the figure below.

PC – based vibratory operating system allows selection of scan rates and scales for work-piece acceleration and excitation frequency, together with exciter power consumption.    Green is used as the initial pre-treatment scan color, functioning as a baseline / reference, while red is used as the post-treatment scan color.

Typical changes seen during a vibratory stress relief treatment are resonance peak growth and  peak shifting, most often but not always, in the direction of lower excitation frequency (to the left on the chart).  The chart shown above is an exception to this general rule.

Detailed descriptions, specifications and photos of the apparatus used to generate vibration, plus equipment used to gather and record vibration data are included, together with identification of key equipment performance criteria.