Failure Prevention and Unconventional Failures: Unusual & Unconventional Failures & Failure Analysis
Program Organizers: Andrew Havics, PH2 LLC; James Lane, Rimkus Consulting Group Inc; Burak Akyuz, Applied Technical Services Inc; Pierre Dupont, UMONS, Faculté Polytechnique de MONS (FPMs)
Wednesday 8:00 AM
October 2, 2019
Location: Oregon Convention Center
Session Chair: Joseph Lemberg, Exponent; Conrad Park, Case Western Reserve University; Erik Mueller , National Transportation Safety Board; Craig Schroeder , Element
8:00 AM Invited
When a Highway Bridge Suddenly Lifts Its Up Without Prior Announcement … !: Pierre Dupont1; 1UMONS, Faculté Polytechnique de MONS (FPMs)
This presentation shows a nowadays failure case study of a 4lanes highway semi-harp cable bridge crossing the river MEUSE near LIEGE, Belgium and where the steel anchorages of a tensionning connecting rod suddently fractured an early winter morning of Ferbruary 2018. This bridge, built in 1984 with a total length of309[m] &a maximum span of126[m], hunged by 24cables sees its main structural steel beam bent to the bank by the use of a"nailing technique". This is specifically at one of these nails that the suddent fracture occured fortunately making more fears than harm but lifting instantaneously the lanes of more than500[mm]. A detailled description of the problem will be made revealing the most probable root cause, showing that very fine &seemly unsignificant design details can acts against safety while years of service are considered. A way to point out that time&details may put every engineer on guards!
As Designed Does Not Always Equal as Manufactured: Charles White1; 1Kettering University
In a production situation, what is obvious is not always easily recognized by the investigator. The author will discuss and highlight case studies of production trouble shooting in Manufacturing such as line speed increases without appropriate adjustments to quality checks. Changes in tooling that result in improvements in production rate but decrease in compliance to specifications and function. Shop floor changes that the engineer never thought of that make the product a success
Common Failures, Uncommon Features: Erhan Ulvan1; 1Acuren Group Inc.
A failure analyst concludes most of the time a common failure type is the culprit for the failure, however, she/he encounters unusual, uncommon features during the investigation. This presentation will give some examples of those uncommon features observed.
9:00 AM Invited
The Power of the "Infinite Smalls" Where Heavy Rude Working Conditions Are Involved !: Pierre Dupont1; 1UMONS, Faculté Polytechnique de MONS (FPMs)
This talk will show through practical industrial case studies how some specific failure modes such as abrasive, adhesive, corrosive wear and rolling contact fatigue can be minimized or nearly avoided by the use of some thin micronscaled surface treatments and especially under so heavy working conditions as those met in pulp&paper, steel casting and polymer industry. A detailled description of the working conditions rudeness of those applications will be done to better show the complete efficiency of these solutions leading sometimes to a time 4 to 5 increase of the lifetimes of the machine components. A review of some specific coatings (Iron Oxydes, DLC, Ceramics, …) showing their composition and properties is previewed. A talk truly oriented on prevention !
Wind-induced Failure of 9m Street Lamp Poles: Milo Kral1; 1University of Canterbury
A street light pole in a new housing development suddenly fractured near its base and collapsed. A vehicle crashed into the fallen pole. Due to the incident and risk of other failures in the hundreds of poles lining the streets, an investigation of the root cause and prevention was conducted. Many other poles were found to be cracked. Evidence showed that the pole failure was preceded by the growth of metal fatigue cracks at the root of welds. The fatigue crack growth was most likely driven by wind-induced vibrations. Strong prevailing winds, the open landscape and height of the poles make this site susceptible. Similar cases, this analysis and prevention will be discussed in detail.
9:40 AM Invited
Failure Analysis of a LORAN C Tower Near Greenland: George Vander Voort1; 1Vander Voort Consulting L.L.C.
The US Coast Guard had a LORAN C tower built on an island off the coast of Greenland. It was 1350 feet tall. It collapsed 289 days after erection. One guy wire broke and the tower collapsed, indicating a poor, non-redundant design. The longer guy wires were broken up using insulators in the cables. The porcelain insulators had no strength in tension, so they had to be loaded in compression using a pin through the porcelain. One pin broke as it was misaligned and fatigue caused it to break. The tower design only considered static stresses, ignoring dynamic stresses. Twice a watchman noticed the guy wire oscillating in a sinusoidal manner and recorded the day and time as this seemed to him to be very odd behavior.
10:00 AM Break
Failure by Design: Andrew Havics1; 1PH2 LLC
Material or component failure are usually looked at as bad events. However, in certain cases a failure is by design. This talk will look at intentional designed failures of materials or devices, generally as safety measures as opposed to say a bolt, which is designed to fail before the clamping members do, but one doesn’t really want the bolt to failure either. Examples of failure by design are thermally activated materials used for fire sprinkler heads or electrical switches in a furnace. Other examples would be blast doors or blast gates or even chain systems for explosion damage reduction, whether from chemical reactions or combustible dust sources.
Metallurgical Failure Analysis of a Fractured Intermediate Coupling: Craig Schroeder1; 1Element
One section of a fractured intermediate coupling was received for metallurgical failure analysis. It was requested that the cause of failure be determined. The intermediate coupling was reportedly used in a sea water pumping assembly that cools a condenser for a power plant. It reportedly ran continuously at one speed and was made from ASTM A743 Grade CF3MN cast stainless steel. The coupling reportedly failed after approximately two years in service. Other couplings made from the same type of stainless steel in similar applications have reportedlybeen in service for decades without failing.
Leak in Water Line 45 Years in the Making: Thomas Traubert1; 1EDT Engineers
An underground municipal drinking water system, installed in 1927, comprised of a reservoir and discharge tunnel, feeding into a 48 inch cast iron piping system, operated for almost 50 years without issue. In 1973 the tunnel was inspected using commercial divers due to indications of leakage observed at grade. The inspection revealed some deficiencies in the tunnel portion of the system that were deemed to be minor, with measures to contain the leakage at the surface implemented. In late 2017, indications of a second, more significant leak was observed in the location of the cast iron pipe. A remotely operated vehicle (ROV) inspection of the pipe revealed a surprising reason as to the mechanism responsible for the leakage.
The Unusual Case of a Not-so-Obvious Brake Line Failure: Erik Mueller1; Stephen Stein1; 1National Transportation Safety Board
On October 17, 2013, a privately-owned general aviation airplane was substantially damaged while landing at an airport in Franklin, NC. During the landing, one of the brakes "locked up", causing the airplane to depart the runway. Substantial amounts of brake fluid were discovered on-scene, leading the National Transportation Safety Board investigators to examine the brake lines. During the investigation of the brake lines, what was initially thought to be a simple fatigue fracture turned out to be a complex failure mechanism involving exfoliation, fretting, and galvanic corrosion. This talk will highlight the findings of the accident investigation, as well as the recommendations to prevent this synergistic collection of events from happening in the future.
Investigation of an Amphibious Duck-boat Fracture in Seattle, WA: Adrienne Lamm1; 1National Transportation Safety Board
On September 24, 2015, a DUKW amphibious passenger vehicle (aka “duck-boat”) traveling north on Route 99 in Seattle, Washington crossed the center line into the southbound lanes of oncoming traffic. The vehicle struck a motorcoach that was traveling south, killing five passengers and injuring others in both vehicles. During the on-scene phase of the investigation, National Transportation Safety Board investigators found the front driver’s side wheel had separated from the DUKW vehicle. The subsequent materials laboratory investigation found that the wheel had fractured from the front axle housing due to fatigue cracking. This presentation will highlight the numerous techniques used in this investigation, including non-destructive inspection, electron microscopy, metallography, and finite element modeling, to determine the cause of this accident. This presentation will also discuss the recommendations that resulted from this investigation to prevent future accidents on this unique vehicle.