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Technical Paper

Flexible Assembly System Implementation

1999-10-06
1999-01-3447
This paper covers issues related to the installation, testing, and production implementation of a large-scale automated wing drilling/fastener installation system. Emphasis is placed on describing the production process, foundation requirements, axes alignment, calibration, testing and implementation. Description will include key hardware features such as the multi-function end effector and spindle end effector. The objective is to convey the complexity of implementing this system as well as reviewing the lessons learned from this experience.
Technical Paper

The Automated NC Mini-Driller

1999-10-06
1999-01-3436
The introduction of a new derivative to an existing aircraft model poses many decisions regarding old versus new. In the case of the introduction of the extended range 767 (the 767-400ER), an entirely new wing design prompted the examination of the then current assembly processes and tooling. The hesitation to build new drill templates for use in the traditional method of second stage wing spar assembly inspired Tool Engineering Management to request the investigation of a low cost automated drilling apparatus. As a result, the Boeing Automated Tools Group and Advanced Integration Technology, Inc. (AIT) developed and implemented mobile numerically controlled mini-drilling machines for post-ASAT I assembly-drilling operations.
Technical Paper

Burr Prevention and Minimization for the Aerospace Industry

1999-06-05
1999-01-2292
Burr research is undeniably highly complex. In order to advance understanding of the process involved several techniques are being implemented. First a detailed and thorough examination of the burr forming process is undertaken. The technique is difficult, intricate and time consuming, but delivers a large amount of vital physical data. This information is then used in the construction of empirical models and, in some case lead to development of FEM models. Finally using the model as a template, related burr formation problems that have not been physically examined can be simulated and the results used to control process planning resulting in the reduction of burr formation. We highlight this process by discussing current areas of research being followed at the University of California in collaboration with Boeing and the Consortium on Deburring and Edge Finishing (CODEF).
Technical Paper

Assessment of the Microbial Control Measures for the Temperature and Humidity Control Subsystem Condensing Heat Exchanger of the International Space Station

1999-07-12
1999-01-2109
In August 1997 NASA/Marshall Space Flight Center (MSFC) began a test with the objective of monitoring the growth of microorganisms on material simulating the surface of the International Space Station (ISS) Temperature and Humidity Control (THC) Condensing Heat Exchanger (CHX). The test addressed the concerns of potential uncontrolled microbial growth on the surface of the THC CHX subsystem. For this study, humidity condensate from a closed manned environment was used as a direct challenge to the surfaces of six cascades in a test set-up. The condensate was collected using a Shuttle-type CHX within the MSFC End-Use Equipment Testing Facility. Panels in four of the six cascades tested were coated with the ISS CHX silver impregnated hydrophilic coating. The remaining two cascade panels were coated with the hydrophilic coating without the antimicrobial component, silver. Results of the fourteen-month study are discussed in this paper.
Technical Paper

CFD Modeling of 2-D Aileron Effectiveness

1999-10-19
1999-01-5618
This paper examines the capability of the Reynolds-averaged thin-layer Navier-Stokes codes to simulate the results from a two-dimensional aileron effectiveness test. This unique test was carried out in the IAR high Reynolds number wind tunnel and addressed the effects of Reynolds number, Mach number and angle-of-attack on aileron effectiveness. The test results showed a highly nonlinear variation of lift for downward trailing edge deflections. It provides a valuable database for using CFD to determine the adequacy of the corrections applied to the experimental data due to the presence of the wind tunnel walls, and for assessing the current CFD capability to model the flowfield with separation. CFD predictions are obtained by using CFL3D with the Spalart-Allmaras turbulence model and TLNS2D with the modified Johnson-King turbulence model.
Technical Paper

Integrated Orbiter/International Space Station Air Quality Analysis for Post-Mission 2A.1 Risk Mitigation

2000-07-10
2000-01-2250
Crewmember ingress of the International Space Station (ISS) before that time accorded by the original ISS assembly sequence, and thus before the ISS capability to adequately control the levels of temperature, humidity, and carbon dioxide, poses significant impacts to ISS Environmental Control and Life Support (ECLS). Among the most significant considerations necessitated by early ingress are those associated with the capability of the Shuttle Transportation System (STS) Orbiter to control the aforementioned levels, the capability of the ISS to deliver the conditioned air among the ISS elements, and the definition and distribution of crewmember metabolic heat, carbon dioxide, and water vapor. Even under the assumption that all Orbiter and ISS elements would be operating as designed, condensation control and crewmember comfort were paramount issues preceding each of the ISS Missions 2A and 2A.1.
Technical Paper

ISS Launch to Activation EVA Cooperative Design

2000-07-10
2000-01-2441
The design challenges presented by the late evolving International Space Station (ISS) Launch to Activation (LTA) thermal concerns required concerted effort and tradeoffs to be made between affected subsystems. The resulting design and mission planning modifications were made with consideration of thermal, electrical power system and extravehicular activity impacts in mind. It was an excellent exercise in cooperative problem solving that allowed each subsystem visibility into potential impacts of their efforts on other related systems and therefore work towards balanced solutions. It was also an excellent exercise in preparing these subsystems for future quick response cooperative problem solving that will be required to support ISS during its lifetime.
Technical Paper

Military Rotorcraft Flight Test Safety in the Age of Joint Ventures

1999-04-13
1999-01-1437
This paper is an explanation of some of the Flight Test Safety (FTS) methods used to reduce the risk associated with military rotorcraft development. Two flight test programs are addressed, the V-22 Osprey tiltrotor and the RAH-66 Comanche helicopter. A short history of the development of each program is provided as background information. Some of the challenges and strengths of joint ventures are also identified and discussed. Four critical elements of an FTS program are identified: 1) Organizational Risk Management (ORM), 2) issue/anomaly resolution, 3) incident recording and corrective action documentation and 4) interface between FTS and other organizations. Methods used in the two programs to address these elements are reviewed and can be applied to other flight test programs.
Technical Paper

Intelligent Damage Adaptive Control for Commercial Air Transports

1999-04-13
1999-01-1436
In situations of unanticipated maneuvers of an aircraft, information must be immediately received by the aircrew for correcting the aircraft flight path to a safe trajectory for continued flight and landing. These maneuvers may be due to failures in the control system, wind gust upsets, or other off-nominal conditions. Also critical are situations of control maneuvers that exceed the normal flight envelope of the aircraft, and providing information to the pilot and control system that will result in safe return to controllable flight. The Intelligent Damage Adaptive Control System (IDACS) operates during flight to detect dangerous conditions of the aircraft and to provide the crew with assistance to restore and to maintain safe control. This system is being developed by Boeing for NASA.
Technical Paper

Asssessment of Waste Processing Technologies for 3 Missions

2001-07-09
2001-01-2365
Choosing the best approach to meet waste processing requirements for long duration space missions should be based on objective selection criteria that provide for subsystem operational availability at the lowest mission cost. Suitable criteria would include robustness, safety, and the minimization of mass, volume, power, cooling, crew time, and resupply requirements for the candidate technologies. The best candidate technologies based on data from historical missions and preliminary data from the Solid Waste Processing and Resource Recovery Workshop (SWPRRW) have been evaluated for cost effectiveness in processing crew waste loads as defined by identified waste models. Both PC and biological approaches were considered for each of three missions: the ISS mission, a Mars transit mission, and a “concentrated exploration” mission for the Mars surface. Results of this analysis are consistent for all three missions considered.
Technical Paper

International Space Station (ISS) United States Carbon Dioxide Removal Assembly Blower Anomaly Resolution

2001-07-09
2001-01-2416
The Carbon Dioxide Removal Assembly (CDRA) is the primary carbon dioxide removal system located in the United States On-Orbit Segment (USOS) Laboratory module ‘Destiny’ and Node 3 on the International Space Station (ISS). CDRA is housed in a standard ISS rack defined as the Atmosphere Revitalization (AR) rack consisting of the CDRA, Trace Contaminant Control Subassembly and Major Constituent Analyzer. The AR subsystem operation and failure detection are controlled automatically using software that has provisions for override control. This paper will present the blower failure that was experienced during AR rack level and Laboratory ECLS integrated testing. The failure description, failure investigation findings and steps taken to return CDRA to flight will be covered.
Technical Paper

CFD Simulation on the Airflow and CO2 Transport in the U.S Lab: International Space Station Flight 5A Configuration

2001-07-09
2001-01-2255
The U. S. Laboratory (USL) module was added to the International Space Station (ISS) in Flight 5A, which would boost the Environmental Control & Life Support System (ECLSS) functional capabilities of the ISS. In the USL cabin aisle way, the air circulation is provided by a Temperature & Humidity Control (THC) system. To provide adequate ventilation under various open/close combinations of the rack panels, it would be very challenging by conducting many tests prior to the launch of Flight 5A. Computational fluid dynamics (CFD) simulation technology is utilized to investigate the airflow in the U.S. Lab for various operating scenarios. A CFD model, which includes the supply diffusers, the return registers, the ventilation of the temporary crew quarter, the gap between the outer pressure shell and all the racks, is modeled. The ventilation performance for the cabin aisle way and air behind panels is addressed.
Technical Paper

The Effect of Gravity Induced Buoyancy on Velocity Measurement in 1-g Environment

2001-07-09
2001-01-2256
The effects of testing cabin ventilation in gravity to meet a requirement for ventilation on orbit were analyzed. Buoyancy is due to the combined presence of a density gradient within the fluid and a body force that is proportional to the fluid density. Since gravity cannot be removed, the test must be conducted with air at as near to constant density as practical in order to remove buoyancy effects. The effects of gravity induced buoyancy force on the velocity field was analyzed by the Richardson number. Computational Fluid Dynamics (CFD) analysis was performed to verify the theoretical methods. The velocity data for a 1-g and a no gravity case were compared. The ratio between local velocity and free stream velocity, u/U∞ were analyzed for the dimensionless parameter, η (= y ✓ U∞/νx). There is a relatively sharp rise in the profile near the wall and an overshoot of the velocity beyond its free stream value.
Technical Paper

Assessment of the OVERFLOW Navier Stokes Code for Various Airplane Components

2001-09-11
2001-01-2976
The OVERFLOW chimera grid Navier Stokes code was used to analyze a wide variety of airplane configurations. The code performed reliably and was found to have comparable accuracy to the structured grid code TLNS3D. It is easier to develop overlapping grid blocks to represent a complex configuration than it is to develop grid blocks that must abut one another. The process is inherently modular. One can add or subtract components like tip-lights, compound winglets, struts, nacelles, tails and fairings at will. The gain in grid simplicity is offset by the complication in specifying block connectivity, however. The overset blocks are typically of better quality, but there is a drawback in that it is not always possible to guarantee flux conservation. The recent development of software for automatic connectivity holds promise for the routine use of OVERFLOW by design engineers.
Technical Paper

An Integrated Human Modeling Simulation Process for the International Space Station, Intra-Vehicular Activity

2001-09-11
2001-01-3035
Defining a process for integrating human modeling within the design and verification activities of the International Space Station (ISS) has proven to be as important as the simulations themselves. The process developed (1) ensured configuration management of the required digital mockups, (2) provided consistent methodology for simulating and analyzing human tasks and hardware layout, (3) facilitated an efficient method of communicating design requirements and relaying satisfaction of contract requirements, and (4) provided substantial cost savings by reducing the amount of late redesign and expensive mockup tests. Human simulation is frequently the last step in the design process. Consequently, the influence it has on product design is minimal and oftentimes being used as a post-design verification tool.
Technical Paper

Forging the Chain – Considerations for Developing a Supply Chain Strategy

2000-05-16
2000-01-1757
Logistics, information exchange, and people all influence the capability and contribution to profits of the supply chain. Understanding how to analyze the current state, and set a strategy to achieve the desired end state is critical to success in the market place. This paper will focus primarily on the acquisition of components for a manufacturing/assembly operation. However, the principles and processes described can be applied to other segments of the chain, such as from the manufacturer to the customer, or to other components of manufacturing such as maintenance, repair and operating (MRO) supplies.
Technical Paper

Assessment of Lithium Hydroxide Conservation Via International Space Station Control of Orbiter Carbon Dioxide

2002-07-15
2002-01-2271
In order to conserve mass and volume, it was proposed that the International Space Station (ISS) control the level of carbon dioxide (CO2) in the Space Shuttle Orbiter while the Orbiter is docked to the ISS. If successful, this would greatly reduce the number of lithium hydroxide (LiOH) canisters required for each ISS-related Orbiter mission. Because of the impact on the Orbiter Environmental Control and Life Support Subsystem (ECLSS), as well as on the Orbiter flight manifest, a Space Shuttle Program (SSP) analysis was necessary. STS-108 (ISS UF1) pre-flight analysis using the Personal Computer Thermal Analyzer Program (PCTAP) predicted that the ISS would be able to control the level of CO2 in the Orbiter (and throughout the stack) under nominal conditions with no supplemental LiOH required. This analysis assumed that the Carbon Dioxide Removal Assembly (CDRA) located in the U.S.
Technical Paper

Experimental Study of Hole Quality in Drilling of Titanium Alloy (6AL-4V)

2002-04-16
2002-01-1517
This paper presents the experimental study of hole quality parameters in the drilling of titanium alloy (6Al-4V). Titanium alloy plates were drilled dry using three types of solid carbide drills i.e. 2-flute helical twist drill, straight flute and three-flute drill. The objective was to study the effects of process parameters like feed rate, speed and drill bit geometry on the hole quality features. Typical hole quality features in a drilling process are the hole quality measures such as surface roughness, hole diameter, hole roundness and burr height. The results indicate that proper selection of speed, feed rate, and drill geometry can optimize metal removal rate and hole quality.
Technical Paper

Advanced Technology in Future Metal Cutting for Airframe Manufacturing

2002-04-16
2002-01-1515
Metal cutting is a substantial constituent of airframe manufacturing. During the past several decades, it has evolved significantly. However, most of the changes and improvement were initiated by the machine tool industry and cutting tool industry, thus these new technologies is generally applicable to all industries. Among them, few are developed especially for the airframe manufacture. Therefore, the potential of high efficiency could not be fully explored. In order to deal with severe competition, the aerospace industry needs improvement with a focus on achieving low cost through high efficiency. The direction of research and development in parts machining must comply with lean manufacturing principles and must enhance competitiveness. This article is being forwarded to discuss the trend of new developments in the metal cutting of airframe parts. Primary driving forces of this movement, such as managers, scientists, and engineers, have provided significant influence to this trend.
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