Missouri University of Science and Technology

About: Missouri University of Science and Technology is a education organization based out in Rolla, Missouri, United States. It is known for research contribution in the topics: Control theory & Artificial neural network. The organization has 9380 authors who have published 21161 publications receiving 462544 citations. The organization is also known as: Missouri S&T & University of Missouri–Rolla.

A Finite-Element Approach for Nonlinear Panel Flutter

Abstract: A finite-element approach has been developed for determining nonlinear flutter characteristics of twodimensional panels, based on aerodynamic forces from quasi-steady aerodynamic theory. The stiffness equations of motion, iterative solution procedure, and convergence characteristics are presented. Comparisons are made with linear flutter and large amplitude vibration results and demonstrate that good accuracy is obtained. Nonlinear flutter results are presented; effects of aerodynamic damping, boundary support conditions, and initial in-plane forces are included.

Residual Stresses in Cold‐Formed Steel Members

Abstract: An extensive experimental investigation of the residual stresses in cold‐formed steel members is presented. The electrical discharge machining (EDM) technique is used to cut coupons for residual stress measurement. As compared to the conventional saw‐cutting method, the EDM technique greatly reduces the external disturbance during the machining of a thin‐walled section caused by heating, clamping, and vibration. The experimental results provide a further understanding of the magnitude and distribution of the residual stresses in cold‐formed steel sections, which are found to be quite different from the residual stresses in hot‐rolled steel shapes. Based on the experimental findings, an idealized distribution pattern of the residual stresses in a cold‐formed channel section is outlined. Finally, the yielding propagation in an axially compressed cold‐formed steel section is described, and an equation for predicting the extent of yielding is derived.

Fabrication and Characterization of a Functionally Graded Material from Ti-6Al-4V to SS316 by Laser Metal Deposition

Abstract: In this study, laser metal deposition (LMD) was employed to explore a new fabrication process for producing a functionally graded material (FGM) from Ti-6Al-4V to SS316. A transition composition route was introduced (Ti-6Al-4V→V→Cr→Fe→SS316) to avoid the intermetallic phases between Ti-6Al-4V and SS316. A thin wall sample was fabricated via LMD by following the transition composition route. Microstructure characterization and composition distribution analyses were performed by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The SEM images depicted the microstructural morphology of the FGM sample. The element gradient distribution determined by the EDS results may reflect the FGM transition composition route design. X-ray diffraction tests were conducted and the results demonstrated that the generation of intermetallic phases effectively avoided following the composition route. The Vickers hardness test was used to determine the Vickers hardness number (VHN) distribution from Ti-6Al-4V to SS316. The VHN results showed that no significant formation of hard brittle phases occurred in the LMD procedure.

Disorder-induced rounding of certain quantum phase transitions.

Abstract: We study the influence of quenched disorder on quantum phase transitions in systems with over-damped dynamics. For Ising order-parameter symmetry disorder destroys the sharp phase transition by rounding because a static order parameter can develop on rare spatial regions. This leads to an exponential dependence of the order parameter on the coupling constant. At finite temperatures the static order on the rare regions is destroyed. This restores the phase transition and leads to a double-exponential relation between critical temperature and coupling strength. We discuss the behavior based on Lifshitz-tail arguments and illustrate the results by simulations of a model system.

Flow Transport and Inclusion Motion in Steel Continuous-Casting Mold under Submerged Entry Nozzle Clogging Condition

Abstract: Clogging of the submerged entry nozzle (SEN) is a serious problem during the continuous casting of steel, due to its influence on the casting operations and product quality. Fluid-flow-related phenomena in the continuous casting mold region with the SEN clogging are investigated in the current article, including the quantitative evaluation of inclusion removal, slag entrainment, heat transfer, and the prediction of breakouts. The calculations indicate that, in order to accurately simulate the fluid flow in the mold region, the SEN should be connected with the mold region and the two should be calculated together. In addition, the whole mold region has to be calculated. Clogging at the SEN at one side induces asymmetrical jets from the two outports; thus, the fluid flow in the mold is asymmetrical. In addition, more inclusions are carried by the flow to the top surface of the nonclogged side, and the slab at the nonclogged side has a lower quality. With SEN one-sided clogging, inclusions travel a much larger distance, on average, before they escape from the top or move to the bottom. The overall inclusion entrainment fraction from the entire top surface for inclusions of any size is less than 10 pct. A higher turbulence energy and a larger surface velocity induce more inclusion entrainment from the top surface. Smaller inclusions are more easily entrained into the steel than are larger ones. More >200-μm inclusions can be entrained into the molten steel from the top slag with SEN clogging than without clogging. The SEN one-sided clogging generates an asymmetrical temperature distribution in the mold; it also generates temperatures higher than the liquidus temperature at some locations of the solidified shell, which increases the risk of breakouts. The SEN clogging should be minimized in order to achieve a uniform steel cleanliness, a cleaner steel, and a safe continuous casting operation.