Plasma Facing Component Design Through Multiphysics Simulation

Spot welding palys a key role in increasing productivity and weight reduction of the final products. This paper proposes a systematic approach on the design of spot weld configuration, dealing with the requried number and location of spot weld joints under the given design parameters, such as the applied loads, lap area, and individual spot weld strength. The optimal design of a spot-welded joint is postulated as a state when the safety factors of all spot weld points (i) are evenly distributed and (ii) reach maximum value. A CAD program is developed to arrange the optimal location of each spot weld based on the derived objective function and constraints. The CAD tool integrates the optimization procedure with Finite Element Analysis (FEA) code through an interface. The interface automatically provides geometrical data and mesh configuration for different spot weld locations to FEA model. It also extracts the transmitted load of each spot weld from the FEA code, and allows the optimization code predict an improved arrangement of spot weld locations. The feasibility of the developed approach is demonstrated by the selected examples.

Experiment and design methodology of a double-layered flange connection in axial loads

Optimization of welding distortion of vacuum vessel for nuclear fusion based on finite element analysis

The mechanical behavior of bolted connections in high-strength (HS) steel structures is a matter of concern, since the less ductility compared to mild steels may affect the load transfer and stress distribution of bolted connections. Conducting advanced finite element (FE) analysis incorporating validated material plasticity and ductile fracture criterion allows for a deeper understanding for the load transfer mechanism of HS steel joints. This paper focused on the plasticity and ductile fracture behaviors of HS (S700MC and S960Q) center-holed (CH) plates under tension, which are the essential component in bolted connections. Firstly, a combined linear and power law was used to calibrate and describe the post-necking stress–strain relations of the investigated HS steels. Then, a void-growth-model based on Rice–Tracey criterion was used to simulate the ductile fracture of five groups of CH plates with different hole diameters. The tensile strength and deformation capacity of the CH plates were discussed. The results showed that S700MC had a strain-hardening plasticity until the tensile fracture, while S960Q had a strain-hardening plasticity with a strain-softening behavior followed near the tensile fracture. Incorporating the calibrated plasticity and ductile fracture criterion in FE analyses generated close force-displacement curves as the experimental results. The equation specified in Eurocode produced conservative predictions for the net cross-sectional tensile strength of the investigated HS steels.

Dynamic behavior of a wall-mounted air conditioner indoor unit is analyzed under drop impact condition. For simulation analysis, a finite element analysis code, known as Ansys Autodyn, is used. Physical drop tests are performed according to ASTM D5276 and ASTM D880 standards and strain gauges are used to measure the effective strains by attaching to specific areas subjected to excessive deformation. By recording drop test with high speed camera, the impact contact duration is also detected. By comparing experimental and numerical results, the validation of finite element analysis is performed. Product improvements are made for the damaged areas and validated by drop test. Conducting physical drop tests with strain gauges together with finite element analysis decreases product development lead time, reduces development costs and eliminates the product’s potential risks in advance. The approach presented with this work can be a reference guide for assessing the dynamic response of impact sensitive home and industrials applicants.

This paper discusses the lessons the author learned in his attempts to parallelize linear finite element analysis (FEA) code for 2D structures using MPI. Three versions of an FEA code obtained by using three different solution techniques were parallelized using the method of domain decomposition. The parallel programs showed excellent speed up on an IBM SP1 when 2 and 4 processors were used. The speed up was not quite as good when 8 or 16 processors were used. It is suspected that the communication pattern to assemble and disseminate nodal information is the bottleneck when more processes are used. The future course of work on the subject is discussed.

Analysis of regional wear failure of crankshaft pair of heavy duty engine

Advanced finite element analysis (FEA) is carried out to simulate the off-axis crushing process of glass/epoxy twill/weave composite box structures. The FE results were compared to relevant experimental result and it was shown that the applied model is capable to predict the damage behaviour and energy absorption of composite box aero-structures under off-axis loading condition.

This paper presents the performance investigation and design technology of Line Start-up Permanent Magnet Synchronous Motor(LSPMSM) with super premium efficiency, including design consideration and evaluation for motor starting-up, key performance, advanced finite element analysis(FEA) for the design, improvement and verification, prototype build and test, design and test data comparison to Premium® Efficient Induction Motor(PEIM). To assess the design technology, LSPMSM prototype was built amended from a PEIM with the same frame, stator punching and rated output. Based on the prototype test, two novel improvement designs and analyses have been done to eliminate the noise and vibration. Additionally, the comparisons with PEIM on power factor, efficiency, frame size and active material consumption indicated the significant performance improvement and active material cost down can be achieved by LSPMSM.

It is well known that even the most advanced Finite Element Analysis (FEA) version is not able to predict friction coefficients among materials. This paper presents an alternative and experimental method based on Design of Experiments (DOE) to determine the friction coefficient between polycarbonate blades against rubber belt. Those experiments correlate ore, lubricant and pressure to determine the friction coefficients in the interface between these materials with polycarbonate and rubber belt. The experiments results are of extreme importance for polycarbonate application on belt conveyor scraper and other applications involving polymeric surfaces under friction.

Hydrocarbon migration after plug and abandonment (P&A) operations negates well integrity and threatens the environment. A section milling procedure for P&A that achieves rock to rock bond eliminates the risk of releasing fluids and gases to surface. This section milling procedure usually involves milling a window in the inner casing and then creating another window in the adjacent outer casing. The tool developed for this process is commonly known as dual string section milling (DSSM) tool. Simulations using advanced finite element analysis (FEA) and computational fluid dynamics (CFD) prior to prototype manufacturing is an extremely useful guide for predicting performance, optimizing design and avoiding costly oversights. This results in higher quality of design of pioneering or innovative products while reducing development costs and time to deliver tools to field. The scope of this paper is to discuss design optimization using CFD that resulted in efficient flow distribution leading to elimination of wash out issues during field runs, while highlighting case studies summary based on design changes made to the new dual string section milling tool. Initial testing of dual string section milling tool design was done on test drilling rig that revealed some erosion prone areas in the tool; this design was modified using CFD to eliminate these erosion prone areas. However, during field runs in salt dome reservoir applications, the erosion issues reappeared in critical flow areas. Further CFD analysis was conducted to eliminate erosion in critical areas to formulate the final product design. The goal was to develop an optimized design delivering extended milling times when the section window requirements were 100 feet or more without any washout or erosion issues while using high pump flow rates. This paper discusses the optimized dual string section milling technology using advanced computational techniques. The development of this technology is an enormous time saving for operators versus using conventional methods- in one offshore field case it resulted in more than 20 days savings in milling time.

Design and manufacturing of resistive wall mode control coil of JT-60SA

The procedures developed by Exxon Production Research Company (EPR) for evaluating the performance of premium tubing and casing threaded connection designs using a combination of nonlinear finite element analysis (FEA) and full-scale physical tests are described in this paper. Over the past several years, EPR has developed advanced techniques for nonlinear FEA to accurately and efficiently calculate the stresses and deformations in threaded connections. Concurrently, EPR's Tubular Goods Test Facility (TGTF) was constructed to assist in verification of FEA models and to conduct full-scale physical tests. Evaluation procedures have been developed that are based on using the combined results of state-of-the-art nonlinear FEA and rigorous full-scale physical tests. Finite element models are "linked" to full-scale tests to form the tools for evaluating threaded connections. Several years of experience in implementing these two evaluation tools together have revealed a unique and valuable synergism between analytical models and physical tests. EPR's evaluation philosophy is to use knowledge gained from advanced accurate FEA to test fewer connections with greater confidence in the results.

Remaining tritium in the vacuum vessel after the first deuterium plasma experimental campaign conducted over four months was investigated in the large helical device (LHD) for the first time in stellarator/heliotron devices by using the tritium imaging plate technique. In-vessel components such as divertor tiles and first wall panels, and long-term material probes retrieved from the vacuum vessel were analyzed. The in-vessel component in which tritium remained most densely is the baffle part of divertor tiles made of graphite retrieved from the inboard-side divertor. Asymmetric tritium retention is observed on divertor tiles located at magnetically symmetric positions, and can be attributed to the toroidal field direction dependence of the asymmetric loss of energetic tritons generated by deuterium–deuterium nuclear fusion reactions. On the first wall, tritium remained in a deposited layer, which mainly consists of carbon.

Thermal mechanical characteristics research of HL-2M vacuum vessel during baking