A transient response analysis of the space shuttle vehicle during liftoff

A proposed transient response method is formulated for the liftoff analysis of the space shuttle vehicles. It uses a power series approximation with unknown coefficients for the interface forces between the space shuttle and mobile launch platform. This allows the equation of motion of the two structures to be solved separately with the unknown coefficients at the end of each step. These coefficients are obtained by enforcing the interface compatibility conditions between the two structures. Once the unknown coefficients are determined, the total response is computed for that time step. The method is validated by a numerical example of a cantilevered beam and by the liftoff analysis of the space shuttle vehicles. The proposed method is compared to an iterative transient response analysis method used by Martin Marietta for their space shuttle liftoff analysis. It is shown that the proposed method uses less computer time than the iterative method and does not require as small a time step for integration. The space shuttle vehicle model is reduced using two different types of component mode synthesis (CMS) methods, the Lanczos method and the Craig and Bampton CMS method. By varying the cutoff frequency in the Craig and Bampton method it was shown that the space shuttle interface loads can be computed with reasonable accuracy. Both the Lanczos CMS method and Craig and Bampton CMS method give similar results. A substantial amount of computer time is saved using the Lanczos CMS method over that of the Craig and Bampton method. However, when trying to compute a large number of Lanczos vectors, input/output computer time increased and increased the overall computer time. The application of several liftoff release mechanisms that can be adapted to the proposed method are discussed

A Transient Response Method for Linear Coupled Substructures

A method is presented for determining the transient response of a discrete coordinate model of a linear structural system composed of substructures. The method is applicable to systems consisting of any number of substructures, both determinate and indeterminate interface boundaries, and any topological arrangement of the substructures. The method is simple to implement from a computational point of view because the equations of motion of each of the substructures are solved independently, and the interface boundary compatibility conditions are enforced at each integration time step by a matrix multiplication. The method is demonstrated for a structural system consisting of two beam segments and acted upon by a time dependent force. The numerical results from the demonstration problem validates the accuracy of the method. The application of this method to structural systems with changing interface boundary conditions between substructures is discussed

Ascent Aerodynamic Pressure Distributions on WB001

To support the reusable launch vehicle concept study, the aerodynamic data and surface pressure for WB001 were predicted using three computational fluid dynamic (CFD) codes at several flow conditions between code to code and code to aerodynamic database as well as available experimental data. A set of particular solutions have been selected and recommended for use in preliminary conceptual designs. These computational fluid dynamic (CFD) results have also been provided to the structure group for wing loading analysis

A Perspective on Development Flight Instrumentation and Flight Test Analysis Plans for Ares I-X

NASA. s Constellation Program will take a significant step toward completion of the Ares I crew launch vehicle with the flight test of Ares I-X and completion of the Ares I-X post-flight evaluation. The Ares I-X flight test vehicle is an ascent development flight test that will acquire flight data early enough to impact the design and development of the Ares I. As the primary customer for flight data from the Ares I-X mission, Ares I has been the major driver in the definition of the Development Flight Instrumentation (DFI). This paper focuses on the DFI development process and the plans for post-flight evaluation of the resulting data to impact the Ares I design. Efforts for determining the DFI for Ares I-X began in the fall of 2005, and significant effort to refine and implement the Ares I-X DFI has been expended since that time. This paper will present a perspective in the development and implementation of the DFI. Emphasis will be placed on the process by which the list was established and changes were made to that list due to imposed constraints. The paper will also discuss the plans for the analysis of the DFI data following the flight and a summary of flight evaluation tasks to be performed in support of tools and models validation for design and development

National Launch System cycle 1 loads and models data book

This document contains preliminary cycle 1 loads for the National Launch System (NLS) 1 and 2 vehicles. The loads provided and recommended as design loads represent the maximum load expected during prelaunch and flight regimes, i.e., limit loads, except that propellant tank ullage pressure has not been included. Ullage pressure should be added to the loads book values for cases where the addition results in higher loads. The loads must be multiplied by the appropriate factors of safety to determine the ultimate loads for which the structure must be capable

Targeting Epigenetic Mechanisms in Endometriosis

Endometriosis is a complex and elusive gynecological disease in which the inner lining of the uterus grows in locations outside of the uterus and forms lesions. It is known to affect 1 in 9 women of reproductive age worldwide. Symptoms of endometriosis include severe pain, heavy periods, and infertility. While multiple theories of origin exist, none fully encompass all aspects of the disease, although all theories agree that this is an inflammation-driven disease. Due to this, many researchers are turning towards epigenetics to explain the initiation and progression of endometriosis. However, what is causing these epigenetic changes is still a mystery. We hypothesize that peritoneal fluid (PF) from women with endometriosis, full of chemokines, cytokines, and inflammatory molecules, is the initiator behind the changes seen, specifically the Polycomb repressive complex 2 (PRC2) and its catalytic subunit Enhancer of zeste homolog 2 (EZH2). We noted that there was an upregulation of the PRC2 complex and EZH2 in tissue from women with endometriosis. This upregulation was also seen when endometrial cells were treated with PF from women with endometriosis. miR-155 was also shown to be upregulated in the endometrial lesions and endo PF treated cells examined. Interactions between EZH2 and other genes that may be mechanistically working in the pathogenesis of endometriosis were seen through the use of ChIP-qPCR. The results of this study showed us that the PF from women with endometriosis is playing a role in initiating epigenetic mechanisms as well as providing us a potential novel cross-talk between miR-155 and the PRC2 complex. We used the results of upregulation of EZH2 due to PF from women with endometriosis and examined whether these changes could be inhibited or reversed through targeting an inflammatory pathway, the CXCR4- CXCL12-CXCR7 axis, in endometriosis through the use of a CXCR4 agonist AMD3100. We also examined if the EZH2 inhibitor GSK126 would target this inflammatory pathway. Both cells and tissues from women without endometriosis were treated with a combination of control or endo PF and/or AMD3100 or GSK126 in order to examine gene expression as well as changes in cell proliferation and migration. Endometrial PF was shown to increase the expression of EZH2, as well as the proliferation of the cells. When AMD3100 or GSK126 was added to the cells and the tissues in the presence of endometriosis PF, dual results were noted, suggesting that a one-sided approach, targeting just the inflammation or just the epigenetic mechanisms is not the correct approach for treatment. The best alteration of gene expression, suppression of cell proliferation, and suppression of migration was noted when combining the two compounds for a dual-sided treatment. Overall, the studies presented in this thesis show that both epigenetic mechanisms and inflammatory pathways drive the progression of endometriosis. Further studies will examine the effects that the compounds used in these studies have in animal models of endometriosis where lesion growth and pain levels will be observed