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Metallurgy | Failure of Wire Rope Cables- Aerial Bucket LiftA tree trimmer died when the aerial bucket lift (cherry picker) he was working from collapsed and fell to the ground. The bucket is positioned via a combination of booms, hydraulic cylinders and wire rope cables. Wire rope cables consist of many small diameter wires wound together into strands and then these strands are wound together into a cable. Pictured to the right is a cross section of a wire rope cable. After the accident, it was found that the cables had snapped. However, further examination and testing of the cables indicated that they were in good condition at the time of the accident and basically were not the cause of the accident. |
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| This was accomplished via scanning electron microscopy and mechanical tensile testing. It was further determined that the cables failed most likely due to slack in the hydraulic and/or cable system. The dynamic loading of the slack broke the cables. It turned out that the hydraulic cylinder had just been repaired before the accident and that the mechanic failed to put hydraulic fluid back into the cylinder. In addition to the cable failure analysis, the case involved design defects in the aerial lift truck, warning labels, warnings in the repair manuals, and hydraulics. Dr. Michael Fox testified in California Court about all these issues. Dr. Fox is a nationally recognized metallurgy expert, corrosion expert and failure analysis expert who has published numerous peer-reviewed, scientific papers in these fields. He worked for years as a bench scientist and a research manager in the fields of corrosion, metallurgy and failure analysis of materials in nuclear reactors. Dr. Michael Fox, the Founder of Chemical Accident Reconstruction Services (www.chemaxx.com), can be contacted at service@chemaxx.com or 800-MIKE-FOX (645-3369). ©2005 CHEMAXX, INC | ||