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In This Issue

· FTI Supports F-35 Lightning II Production...

· Sikorsky Announces FTI as a Supplier Team Member for S-97 Prototype...

· ForceMate Allows Replacement of Same Sized Bushing - No Oversize Needed...

· Len Reid Wins 2011 Lincoln Award...

· FTI Cold Expansion Training Courses...

· Upcoming FTI Trade Shows, Conferences, & Events




Fatigue Technology supports the production of the F-35 Lightning II. Yes, we have a lot of our products on this aircraft, including some very innovative cold expansion technology, but we also firmly believe in the value, tactical advantage, and security this fighter will provide to our military, our country, and to our foreign partners. We see every day the strain being placed on our military in trying to keep our older military aircraft flying. It is time for a new aircraft to take over. The F-35 will help the U.S. and its allies defend freedom for decades to come. The program will also provide 260,000 jobs in the U.S. including the 185 employees here at FTI. We are working hard to help get the word out about the importance of the F-35 program, and over the years we have partnered with the Lockheed Martin Corporation in many public relations initiatives to accomplish this.

FTI and the F-35 in the News
FTI is championing the program to media outlets here in the Pacific Northwest and nationally. We were recently quoted in the Puget Sound Business Journal as one of 23 local suppliers to the Joint Strike Fighter. FTI was also in the Tacoma News Tribune concerning the U.S. Congressional debate about the program. This article was picked up by media outlets nationwide. We have also opened up our manufacturing facility to media photographers to showcase the products and the people involved with the JSF.

Involved with Grassroots Efforts
FTI participated in Lockheed Martin's grassroots promotional video titled "Who We Are", which focuses on the people and the innovation behind this 5th generation stealth aircraft. The purpose of the video is to inform the public about the importance of the F-35 fighter to our nation and to get them involved in signing a statement of support for the program. Our own Atoa Siliaga, Lead Material Hander, was featured in the video.

Atoa Siliaga, Lead Material Handler at FTI
Atoa Siliaga, Lead Material Handler Preparing for the Promotional Video

JSF Cockpit Demonstrator Visits FTI
In August of 2010, FTI hosted the F-35 cockpit demonstrator at our corporate headquarters in Seattle, WA. Local and national political representatives, the news media, selected suppliers, and key employees were given the opportunity to "fly" the demonstrator to better appreciate the attributes of the aircraft. The Lockheed Martin team was available to answer questions concerning the JSF's capabilities, the program's current status, and provided information related to the economic impact and contributions made by the area suppliers. We are looking forward to hosting the demonstrator again in the near future.  

F-35 Lightning II Cockpit Demonstrator
F-35 Lightning II Cockpit Demonstrator

Washington DC Meetings
Last March, FTI took part in a concerted effort with Lockheed Martin and other F-35 suppliers to meet with U.S. Senators and Congressmen in Washington DC. FTI sat down with Washington State representatives to voice our support for the F-35 and to validate its importance to our local community and economy. We are planning to meet again with them in March of 2012.

At FTI, we not only stand behind our products and services, but we also stand behind our customers' products (like the JSF) and support their efforts to provide the next generation of aircraft. For more information, please contact us at





As part of the Supplier Team for the S-97 RAIDER Helicopter, FTI products and solutions will be designed and integrated into this next-generation, light tactical helicopter.  FTI joins 35 other companies with Sikorsky in assembling two prototype helicopters for evaluation by the U.S. Military.  The RAIDER program will demonstrate the military applications of Sikorsky's break-through X2 rotorcraft design, which provides double the cruise speed of conventional helicopters.  The prototype helicopters will be available for simulated military testing by early 2014.

Sikorsky S-97 RAIDER Helicopter
Sikorsky S-97 RAIDER Helicopter




By Joy Ransom, Materials Test Facilities Manager

Lugs and clevises in aircraft and rotorcraft applications typically incorporate bushings that can provide a replaceable wear surface. FTI's ForceMate bushings are often used in these applications because they are installed with a high interference, which has been previously shown to provide a fatigue life benefit as compared to a non-bushed or shrink-fit bushed hole.  When bushings are required to be replaced, a standard practice is to remove the bushing and check the hole for damage.  If there is no damage in the hole, it would be preferable to use the same bushing to replace the removed bushing instead of requiring material to be removed from the structure to install an oversize bushing.  Tests have shown that this can be accomplished using ForceMate Bushings.

The ForceMate system involves cold expansion of an initially clearance fit bushing into a hole.  A specially sized bushing, with a proprietary lubricant on the inside surface, is radially expanded into the hole using a tapered expansion mandrel.  The process of expanding the bushing will yield the bushing in the hole, creating an interference fit, typically greater than 0.005 inch (0127 mm).  FTI has bushing removal tooling that works with the same installation tooling but with different attachment parts that pull the bushings from the structure and should not cause damage (such as galling) to the hole.  When the ForceMate bushing is removed, the hole in the structure will often be larger than the hole diameter prior to the initial installation.  For aluminum alloys, the diameter may increase as much as 0.008 inch (0.203 mm).  For steel and titanium structure, the increase in hole diameter may be lower, around 0.002 to 0.004 inch (0.051 to 0.102 mm) after bushing removal. 

The standard hole tolerance required for a ForceMate bushing installation is 0.002 - 0.003 inch (0.051 - 0.076 mm).  The hole diameter increase from installing the ForceMate bushings would typically cause the hole diameter to fall outside the tolerance for a nominal bushing.  Standard practice is to rework the hole and install an oversize bushing.  But, oversizing the hole may not be the most practical solution.  Testing has shown that re-installing a nominal ForceMate bushing does not reduce the fatigue life as compared to a single ForceMate installation. 

Bushings are designed with retention and fatigue life in mind.  A bushing should stay in the hole and not be prone to migration (retention) and/or fretting in the hole.   Because the hole in the structure increases after the initial installation of the ForceMate bushing, if a ForceMate bushing of the same dimensions is then re-installed in the hole the interference may be reduced but the strain state stays relatively unchanged (Figure 1).  A test was performed with steel BlueCoated ForceMate bushings installed into an aluminum lug comparing the first installation to two or three re-installations.  For the multiple bushing installation tests, the initial bushing removal required a minimum of 4700 lbf (10.9 kN) to remove.  A second bushing was installed and in some specimens the second bushing was removed requiring a minimum force of 3700 lbf (16.4 kN).  After the second bushing was removed a third bushing was installed.  Fatigue testing was performed to compare a single bushing installed, to the lugs with two and three bushings installed.  An additional data set was included after the first bushing was removed, the hole was resized and a first oversize bushing was installed.  The minimum fatigue life for all the datasets were similar. 

Parent Material Stress-Strain Curve
Figure 1. Parent Material Stress-Strain Curve for Bushing Installations

An additional evaluation was performed to repeat the installation and removal process up to 20 times using nominal bushings in aluminum lugs.  Based on the data from the test program, the hole yields the most after the initial installation. With the additional re-installations, the hole diameter remains consistent to the yielded hole diameter (see figure 2 below).  The minimum removal force may be reduced up to 50% of the original minimum removal force in some installations, but there was not a trend of the removal force decreasing over time (Figure 3).  The variability in the retention after the initial installation is probably caused by the tolerance stackups and changes in surface finishes of the bushings and hole.  Constant amplitude fatigue testing was performed on the lugs with bushings installed once, 6 times and 20 times.  The results of this testing showed no significant fatigue reduction from the multiple installations (Figure 4). 

Hole Variation with Multiple Nominal ForceMate Installations
Figure 2. Hole Variation with Multiple Nominal ForceMate Installations


Removal Force Variation with Multiple Nominal ForceMate Installations
Figure 3. Removal Force Variation with Multiple Nominal ForceMate Installations.

Keep in mind, that during the repair of a structure, any damage observed in the bore of the hole or at the surface of the part near the hole should be removed before a ForceMate bushing is installed.  Using oversize bushings allows the hole to be reamed to clean up any damage before the bushing is installed.  On structures where ForceMate bushings are already utilized, the use of the same size bushing might be an option if there is no damage in the parent material.  

The rework options for an installed ForceMate bushing (if there's no damage to the hole) are:
1. Oversize hole and install oversize bushing
2. Install with the same bushing if the hole tolerance is still within the starting hole in the specification
3. Install with the same bushing if the hole is outside tolerance of specification (caution should be taken to be sure of retention variability acceptable for application)

Fatigue Life Variation with Multiple Nominal ForceMate Installations
Figure 4. Fatigue Life Variation with Multiple Nominal ForceMate Installations
(Courtesy of Bell Helicopter)





Len Reid, Vice President, Technology at Fatigue Technology (FTI) and former Wing Commander (LtCol) of the Royal Australian Air Force, has been awarded the 2011 John W. Lincoln Award.

The John W. Lincoln Award was established in 1996 by the aircraft structural integrity community to recognize a distinguished career expert who has made significant contributions toward advancements in flight vehicle structural integrity and safety.  It is named in honor of the late Dr. John W. (Jack) Lincoln and is presented annually during the Aircraft Structural Integrity Program (ASIP) Conference.

Over the past 24 years, Len developed and adapted FTI's cold expansion methods and processes to innovate a number of unique repair solutions incorporated into many of today's military and commercial aircraft structures.  He is either inventor or co-inventor of 21 US and international patents for FTI. 

Len is also a member of a number of professional societies and is actively involved as Chairman of the Puget Sound Chapter of the American Society of Materials where he mentors and encourages young professional engineers.  He has a number of papers published in professional journals and magazines, has presented numerous papers at technical conferences, including ASIP, and has made a significant contribution in the field of aircraft structural integrity and airworthiness.

Len Reid Wins 2011 Lincoln Award
Chuck Babish (left) presents Len Reid (right) with the 2011 John W. Lincoln Award




Basic Cold Expansion Training includes classroom studies as well as hands-on Cold Expansion.  The following topics will be covered and may be customized depending on your specific application and/or use of Cold Expansion systems: 

 *  What is fatigue?
 *  The history of processes used to extend the fatigue crack growth life in fastener filled holes.
 *  The development of the Split Sleeve Cold Expansion (SsCx) process.
 *  Understanding and using the SsCx process specifications.
 *  Proper tooling callouts for cold expanding a hole.
 *  How to cold expand a hole, including proper PowerPak and puller unit operation and safety procedures.
 *  Process parameters and special applications, such as access restrictions, low edge margins, 
    and multi-material stackups.
 *  Review of other Cold Expansion processes, as applicable.

Instructor Cold Expansion Training builds on the basic knowledge and understanding.  Key points are addressed and attendees learn the importance of teaching the cold expansion technology and theory to their colleagues.

The course is tailored to the attendees whether they are Mechanics/Technicians, QA, Tool Room Personnel, Project/Program Managers, or Engineers.

Class sessions are typically 8 or 12 hours in length, and are held in groups of 10 to 15 people.  Upon successful completion of the course, attendants will be awarded a certificate certifying them for use of the Cold Expansion process.

We have scheduled our 2012 Basic and Instructor Cold Expansion training courses at FTI Seattle.  Courses fill up fast so please register early.

- March 20 & 21
- August 14 & 15
- November 13 & 14 

For questions please contact Elaina Yoon at 206.246.2010 x 257 or  




· Aircraft Airworthiness & Sustainment | April 2-5 @ Baltimore, MD | Booth #707

· AHS Forum 68 | May 1-3 @ Fort Worth, TX | Booth #325

· SAMPE | May 21-24 @ Baltimore, MD | Booth #834



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