Redesign of a Failing Jacket for Heat Exchanger:  A section of a heat exchanger jacket was failing on a repeated basis. KES used conventional and FEA techniques to determine the effects of thermal expansion and pressure on the jacket. A combination of thinning, a change in process conditions, and cyclic loadings was determine to be the root cause. KES worked with the client to recommend changes and the heat exchanger has not experienced water jacket failures since.

Repair on Failed Structural Supports for Process Coils:  Steam coils within process kettle were failing. The structural supports securing the coils to the kettle walls were failing as well as cracking in the steam coils, the latter venting into the process and compromising the run. Agitators within the kettles added significant loads to the coils. KES worked with their engineering and maintenance staff to investigate possible root causes, then sent a representative during a turnaround to inspect the various failures. Several techniques, including FEA, were used to assess potential root causes and possible repairs. When the site inspection confirmed a certain root cause, the proposed repair was implemented during the turnaround. The coils have not experienced a failure since implementing the repairs.

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Failed Transmission Linkage:  A power transmission linkage failed catastrophically, shutting down the equipment item. KES performed a 3rd party design audit for the OEM and determined the geometry of the failed linkage, combined with higher and more frequent loadings than previous designs, was the root cause. KES worked with the OEM in redesigning the new component, including performing Kinematic and Finite Element modeling to predict its performance. In addition to the redesigned part being fielded as an immediate fix, the OEM put a set of the entire system into accelerated service to test the equipment, including the new part. The entire system exceeded its design life and the redesigned part exhibited no signs of failure. The figure below shows a photo of the failed part and a stress plot showing stress concentration corresponding to the crack initiation site.

Buckled Support for Mining Platform:  A working platform within a mine failed. The question became could the leg, which initiated the platform collapse, fail at or below the rated capacity or was the platform overloaded or otherwise compromised. The telescoping structure required a nonlinear coupled Finite Element Analysis to determine the buckling load for a range of leg extensions.  Physical testing was conducted in conjunction with numeric modeling. Results showed the legs were likely to fail significantly under the rated capacity when almost fully extended.

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Useful Life Study for Pressure Vessel:  A 20,000 psi vessel was being designed for cyclic service. KES was contracted to provide an ASME Section VIII, Div. 3 analysis to include an estimate of of fatigue life. KES used an elastic-plastic FEA study as well as numeric procedures to examine the vessel and provide a useful life estimate.

Reliability Study for 55 Cubic Yard Clamshell Bucket: A crane bucket manufacturer had a special request for a large capacity lightweight clamshell bucket for transferring pulverized coal from river barges to a feed hopper. There was nothing like this on the market and the OEM had not manufactured anything that large as light weight was it was designed. KES was contracted to provide a 3rd party design audit to determine the suitability of the design for the application and assess its long term reliability. KES examined the structural response throughout the digging and lifting cycle as well as evaluated the consequences of several modes of mis-operation of concern by the OEM, to include hard drops on decking and the potential effects of specified corrosions/erosion. The detailed report was not only accepted by all parties, it was also used by the buyer to evaluate other buckets. The photo shows the bucket dumping its load during a water test, which is more dense and harder to contain than pulverized coal. The buyer ended up doubling their order based on the success of the bucket.

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Reliability Study of Extrusion Header:  A plastic extrusion header was designed to accept flow from two ports and distribute the polymer through large-diameter circular sections with appropriate holes drilled in the underside. The client was concerned about the design's ability to withstand the considerable pressure at elevated pressures at service and upset conditions, particularly at structural discontinuities where several sections came together. KES used Finite Element Analysis to examine the stresses, deflections, and fatigue issues as well as other numeric procedures to determine the effects of flow disruptions on either feed line.

Vehicle Dynamics/Crash Dynamics

Evaluation of a Security Barrier:  An OEM wished to have a "hard stop" gate, that is, one in which the safety of the impacting vehicle occupants is secondary to an assured stop within a certain vehicle mass and velocity set. Several modes of vehicle attack were considered and analyzed in the course of the project. The barrier was successfully tested to Nuclear Regulatory (NUREG) and Naval Specifications.