ASME BPVC Pressure Vessel Consulting Services. Thermal Stress Fatigue Analysis of High Temperature Graphitization Furnace. It seems rare nowadays that an ASME type analysis is performed without an attendant fatigue analysis. We believe it is simply the result of a changing marketplace where our clients are becoming more knowledgeable in their requests and the industry as a whole are requiring greater accuracy in their analysis work. This project was chartered to investigate the service life of a high temperature carbon fiber graphitization furnace. The company had several of these furnaces and they were more than 2. Although they were designed to operate at 1. C, our client wanted to increase the operating temperature to 1. C to maximize production output. The work consisted of idealizing the thermal performance from graphite felt to water cooled steel shell. With this thermal loading, the FEA model of the system was analyzed under thermal and vacuum loading to create a matrix of possible operating states. The analysis work showed that the furnace was well designed and could safely operate at higher temperatures for many more years. ASME Section VIII, Division 2 Nonlinear Fatigue Analysis of Hairpin Heat Exchanger. This work was particularly interesting since the client had experienced fatigue failures along the weld line between the tubesheet and the shell. The complication on this analysis was that the use of compression sleeve fittings to join the components together. As the bolts were preloaded, tubesheet welded section would lock against the main heat exchanger shell. Our analysis work showed that the weld failure was due to over tightening of these locking bolts and not general thermal or pressure loading. The work required a complete nonlinear contact analysis with bolt preload and then application of design loads. The solution was simply to back off on the bolt preload. This was quite surprising to all and saved significant costs to our client. Fatigue Analysis of Multi Chamber Stacked Chamber. A static pressure and fatigue analysis was performed for a four cell stacked simulated moving bed SSMB column to evaluate whether it would meet ASME Section VIII, Div. The structure was modeled in half symmetry with the most conservative side of the structure in the finite element model using a combination of plate and hexahedral solid elements. Fillet welds in the structure were modeled using rigid elements constraining only the translational degrees of freedom DOFs. Releasing the rotational DOFs represent the physics of a single sided fillet weld and allow weld forces to be extracted quickly and easily. The analysis is linear elastic which allowed the stresses to be scaled linearly with pressure. A 7. 5 psi pressure load was applied to the inside of the structure to evaluate the weld stress at the maximum possible pressure. The stress was normalized to a 1 psi load and then scaled to find the weld stress at each pressure in the operating cycle. Fatigue Essentials was leveraged to count the fatigue cycles using the rainflow counting method and calculate the cumulative damage over the lifetime of the pressure vessel. The operating cycle of the SSMB pressure vessel was a series of repeating patterns which were stored as Fatigue Essentials Spectrums. The S N curve for the material was added to Fatigue Essentials from ASME Section VIII, Division 2. With all of the data input into a Fatigue Essentials project file, the cumulative fatigue damage in the welds was calculated at the click of a button. The combination of linear analysis in NX Nastran and Fatigue Essentials provided an efficient, robust method to evaluate the fatigue life of a production pressure vessel. Not only were we able to confidently report to our client that their pressure vessel would not fail during the production. Stress Analysis of High Pressure Ductile Cast Iron SA 3. Hydraulic Manifolds. The challenge to use cast product for a pressure containing component under the ASME code is two fold i a 5x knock down factor from the materials ultimate strength and ii inspection requirements to assure high quality. To make it even more difficult, our client had pressures exceeding 1,0. ASME code requires a 9. Three manifolds were analyzed using the FEA method with the stress results classed using a stress allowable of 6. On a numerical basis, the stress results showed that the manifolds would pass the ASME Section VIII, Division 2 classification but additionally, one had to substantiate how the casting could meet the 9. Based on Predictive Engineerings metallurgical experience AFS member and co author of Handbook of Abrasion Resistant Cast Irons, it was determined that the Dura. Bar casting process would assure that the quality level would be met. Software process engineering plant building heat exchangers hydraulics thermodynamics stress properties. Services relating to cause and effect of catastrophic events occurring at process plants, field sites, and fabrication shops. Based in Texas. Lastly, the client was informed that the ASME code also requires that all castings be hydrostatically tested to 2x their design pressure. This project presents a good example of how we strive to be advocates for a safe design while collaborating with our clients that it can still be manufactured and inspected in an economical manner. Thermal Stress Fatigue Analysis of Evaporative Hairpin Heat Exchanger. Our client requested this analysis due to prior fatigue failures at the intersection between the tubesheet and tubesheet channel i. Although this region was machined out of a solid steel billet, fatigue failures were still noted. Additionally, the hairpin heat exchanger used two large bolted flanges at each end for attachment of the shell side and tube side components. To correctly model these structures, the geometry was idealized into a solid brick finite element mesh with bolt preload applied using a beam element with shell elements at both ends to simulated the nut and head ends. Given the analysis complexity of bolt preload and contact, the model was analyzed using LS DYNA as a nonlinear implicit analyses. The first step was to conduct a steady state conduction analysis to create a thermal profile within the evaporator. Thermal stress results were interpreted using the 2. Golf Driver Shaft X Flex Swing Speed Chart on this page. ASME Section VIII, Division 2 requirements and the evaporator was shown to meet the clients required fatigue life. A side benefit of this work was the ability to show the client that several heavy components of their vessel could be reduced in section size and still meet code requirements. Large Diameter 3. Asme Calculations Software' title='Asme Calculations Software' />Pressure Vessel Lifting Lug Analysis. The purpose of this analysis was to verify that jacking lugs used on several large diameter pressure vessels would not cause damage to PV components such as the skirt, shell and cooling jacket. Starting with existing FE models of the pressure vessels, the jacking lugs are modeled, meshed and attached to the vessels with a glued connection. This connection type allows new components to be added and joined without re meshing existing components. A 6 diameter hydraulic ram is placed under each of the jacking lugs, centered between the gussets. There is a 1 thick doubling plate between the rams and lugs. The jacking lugs transferred load to the doubling plates and hydraulic ram through surface to surface contact. This analysis work showed that the jacking lug design was robust and would not cause stresses in the PV exceeding ASME Section VIII, Division 2 stress classification requirements. Soda Ash Filter Pressure Vessel Sliding Support Frame Analysis.
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