Browse Topic: Historical reference
ABSTRACT The U.S. Army Combat Capabilities Development Command (DEVCOM) Ground Vehicle Systems Center (GVSC) has been developing next generation crew stations over the last several decades. In this paper, the problem space that impacts design development and decisions is discussed. This is followed by a historical overview of crewstation development activities that have evolved over the last 30 years, as well as key lessons learned that must be considered for successful ground vehicle Soldier-vehicle interactions. Lastly, the direction and critical technological focus areas are identified to exploit advancements and meet future combat vehicle system needs. Citation: T. Tierney, “A Perspective on GVSC Crewstation Development and Addressing Future Ground Combat Vehicle Needs,” In Proceedings of the Ground Vehicle Systems Engineering and Technology Symposium (GVSETS), NDIA, Novi, MI, Aug. 15-17, 2023
This aerospace information report (AIR) provides historical design information for various aircraft landing gear and actuation/control systems that may be useful in the design of future systems for similar applications. It presents the basic characteristics, hardware descriptions, functional schematics, and discussions of the actuation mechanisms, controls, and alternate release systems. The report is divided into two basic sections: 1 Landing gear actuation system history from 1876 to the present. This section provides an overview and the defining examples that demonstrate the evolution of landing gear actuation systems to the present day. 2 This section of the report provides an in depth review of various aircraft. A summary table of aircraft detail contained within this section is provided in paragraph 4.1. The intent is to add new and old aircraft retraction/extension systems to this AIR as the data becomes available. NOTES 1 For some aircraft, the description is incomplete, due to
Despite a long history of development, modern spark-ignition (SI) engines are still restricted in obtaining higher thermal efficiency and better performance by knock. Knocking combustion is an abnormal combustion phenomenon caused by the autoignition of unburned air-fuel mixture ahead of the propagating flame front. This work describes investigations into the significance of spark plug location (with respect to inlet and exhaust valve position) on the knock formation mechanism. To facilitate the investigation, four spark plugs were installed in a specialized liner at four equispaced distinct locations to propagate flames from those locations, which provoked a distinct flame propagation from each and thus individual autoignition profiles. Six pressure transducers were arranged to precisely record the pressure oscillations, knock intensities, and combustion characteristics. Four of the six transducers were mounted on the circumference of the liner (each next to one of the spark plugs
General criteria are presented as guidelines for: control device location, resistance, and actuation of hand and foot controls by the machine’s operator. The criteria are based upon physical limitations as defined by human factors engineering principles
Shared Mobility is changing mobility trends of Automotive Industry and its one of the Disruptions. The current vehicle customer usage and life of components are designed majorly for personal vehicle and with factors that comprehend usage of shared vehicles. The usage pattern for customer differ between personal vehicle, shared vehicle & Taxi. In the era of Autonomous and Shared mobility systems, the customer usage and expectation of vehicle condition on each & every ride of vehicle will be a vehicle in good condition on each ride. The vehicle needs systems that will guide or fix the issues on its own, to improve customer satisfaction. We also need a transformation in customer behavior pattern to use shared mobility vehicle as their personal vehicle to improve the life of vehicle hardwares & reduce warranty cost. We will be focusing on Vehicle Closure hardware & mechanisms as that will be the first and major interaction point for customers in vehicle. This gives us an opportunity to
This SAE Standard defines methods and messages to efficiently translate sequences of text and other types of data into and out of indexed values and look-up tables for effective transmission. This document defines: a Methods and Data Elements for handling indexes and strings in ATIS applications and message sets b Message Sets to support the delivery and translations of tables used in such strings c Tables of Nationally standardized strings for use in ATIS message descriptions And examples of each in illustrative portions. While developed for ATIS use, the methods defined in this document are useful for any textual strings in any Telematics applications found both in Intelligent Vehicles and elsewhere
In many fields of technology, examinations of the past can provide insights into the future. This paper reviews the last 20 years of automotive seat comfort development and research as chronicled by SAE’s session titled “Human Factors in Seating Comfort”. Records suggest that “Human Factors in Seating Comfort” has existed as a separate session at SAE’s World Congress since 1999. In that time there have been 148 unique contributions (131 publications). The history is fascinating because it reflects interests of the time that are driven by technology trends, customer wants and needs, and new theories. The list of contributors, in terms of authors and their affiliations, is also telling. It shows shifts in business models and strategies around collaboration. The paper ends with a discussion of what can be learned from this historical review and the major issues to be addressed. One of the more significant contributions of this paper is the reference list. It contains all 131 of SAE’s
Flexible Tooling Systems have been developed as a reconfigurable part support system to enable trimming of multiple part geometries utilizing a single router or waterjet. The driver for this development has been improved part quality, elimination of ergonomic issues associated with manually trimming, and the elimination of cost for part number specific hard tooling and the associated cost for manufacturing, maintenance, and storage. This paper will briefly trace the evolution of aerospace parts trimming history. The remainder of the report will focus on the technical objectives associated with the development of the Next Generation Flexible Tooling System, how they were achieved including the process for validation of each support location in aircraft coordinates. This system is designed to increase part holding accuracy with specific support location validation, and significantly reduce system maintenance costs in wet or dry environments
The moisture/water absorption and microvoids/cracks progression are two well-understood mechanisms that have significant degradation effects on the mechanical properties/behaviors of the polymer-based composites. To theoretically investigate the effects of above two mechanisms, we develop a simple fiber reinforced polymer composites model by employing the internal state variable (ISV) theory. The water content and the anisotropically distributed damage of the composites are considered as two ISVs (the water content is described by a scalar variable and the damage is defined as a second order tensor) whose histories are governed by two specific physically-based evolution equations. The proposed model can be easily cast into a general theoretical framework to capture more polymer composites behaviors such as viscoelasticity, viscoplasticity and the thermal effect. The results predicted by current model are in good agreement with the experimental data, which allows us to implement the
This document sets forth several acceptable methods of laser beam divergence measurement techniques
Reliability analysis of a large-scale system under random dynamic loads can be a very time-consuming task since it requires repeated studies of the system. In many engineering problems, for example, wave loads on an offshore platform, the excitation loads are defined using a power spectral density (PSD) function. For a given PSD function, one needs to generate many time histories to make sure the excitation load is modeled accurately. Global and local approximation methods are available to predict the system response efficiently. Each way has their advantages and shortcomings. The combined approximations (CA) method is an efficient method, which combines the advantages of local and global approximations. This work demonstrates two methodologies that utilize CA to reduce the cost of crude or separable Monte Carlo simulation (MCS) of linear dynamic systems when the excitation loads are defined using PSD functions. The system response is only calculated at a few frequencies within the
This SAE Recommended Practice encompasses the significant factors which determine the effectiveness of a seat system in limiting spinal injury during vertical impacts between the rider and the snowmobile seat system. The document is intended to provide a tool for the development of safer snowmobile seats. It is recognized that the seat is only a portion of the entire vehicle protective suspension system. It is, however, usually required that the seat serve as added protection to the suspension system, since the latter may "bottom out" during a severe impact. The term "seat" refers to the occupant-supporting system not normally considered part of the vehicle suspension or frame system. In some cases, it may include more than the foam cushion. This document provides the minimum requirements for performance of a general seat system, and a description of specific means of evaluating the shock-absorbing characteristics of foam seat cushions using a specific testing procedure and a companion
Abstract - The Warrior Injury Assessment Manikin (WIAMan) was developed to assess injury in Live Fire Test and Evaluation (LFTE) and laboratory development tests of vehicles and vehicle technologies subjected to underbody blast (UBB) loading. While UBB events impart primarily vertical loading, the occupant location in the vehicle relative to the blast can result in some inherent non-vertical, or off-axis loading. In this study, the WIAMan Technology Demonstrator (TD) was subjected to 18 tests with a 350g, 5-ms time duration drop tower pulse using an original equipment manufacturer (OEM) energy attenuating seat in four conditions: purely vertical, 15° forward tilt, 15° rearward tilt, and 15° lateral tilt to simulate the partly off-axis loading of an UBB event. The WIAMan TD showed no signs of damage upon inspection. Time history data indicates the magnitude, curve shape, and timing of the response data were sensitive to the off-axis loading in the lower extremity, pelvis, and spine
Due to improvements in vehicle powertrain performance, friction material fade performance is becoming an important topic. For this reason, needs for studies to improve thermal characteristics of the brake system is increasing. Methods for improving the fade characteristics have several ways to improve the thermal characteristic of friction materials and increase disc capacity. However, increasing disc capacity(size) have some risk of weight and cost rise, and friction factor improvements in friction material tend to cause other problems, such as increasing squeal wire brush noise and increasing metal pick up on disc surface. Therefore, a slot disc study is needed to overcome the problems discussed previously. Currently, there is few research history for slot disc related to fade and metal pickup improvements. Through this study, I found that the slot disc improved the friction material fade properties, but the application of the slot disc could cause air plane noise and worsen the
For six decades, NASA has led the peaceful exploration of space, making discoveries about our planet, our solar system, and our universe. At home, NASA research has made great advances in aviation, helped to develop a commercial space industry, enrich our economy, create jobs, and strengthen national security. Here is just some of what NASA has achieved in its first 60 years
Over the past 60 years, NASA scientists and engineers have developed many advanced technologies and processes. But NASA has also partnered with industry, using commercially available products to complete its missions. Here, some of those companies join NASA in celebrating these collaborative successes
The first “A” in NASA stands for aeronautics — the science of travel through the air. It's as much about flying on airplanes and arriving safely at a destination as it is about astronauts in space. NASA's roots go back to the National Advisory Committee for Aeronautics, established in 1915 to “supervise and direct the scientific study of the problems of flight
In 1977, the National Renewable Energy Laboratory (NREL, Golden, CO) started as the Solar Energy Research Institute (SERI), spurred by national concern during the 1973 oil embargo that caused long lines and high prices at gas stations. Three months after his 1977 inauguration, President Jimmy Carter announced his desire to reduce dependence on foreign oil and invest in alternative energy sources. He created SERI with the mission to launch a new American energy industry, and consolidated oversight of U.S. energy policy into the newly formed U.S. Department of Energy
This SAE Standard provides a definition of a rainflow file format. This type of simple text file would contain all relevant information about the rainflow cycle content of a time history. Included information are Comments, Signal Range, Signal Mean, Number of Cycles, Signal Maximum, Signal Minimum. Rainflow cycle counting has become the most accepted procedure for identifying material fatigue relevant cycles in complex variable amplitude load time histories. The cycle counting methods account for the effects of material plasticity and material memory of prior deformation, and the resulting compressed history information is used by durability analysts to estimate the effects of a given service or test history. Standardization of the rainflow counting methods output files, which is the format addressed by the present standard, is important for reliable information transfer between test and design groups, or different calculation software packages, and thus forms a critical step in the
This SAE Standard provides test procedures, requirements, and guidelines for reflex reflectors
Active suspension was a topic of great research interest near the end of last century. Ultimately broad bandwidth active systems were found to be too expensive in terms of both energy and financial cost. This past work, developing the ultimate vehicle suspension, has relevance for today’s vehicle designers working on more efficient and effective suspension systems for practical vehicles. From a control theorist’s perspective, it provides an interesting case study in the use of “practical” knowledge to allow “better” performance than predicted by theoretically optimal linear controllers. A brief history of active suspension will be introduced. Peter Wright, David Williams, and others at Lotus developed their Lotus modal control concept. In a parallel effort, Dean Karnopp presented the notion of inertial (Skyhook) damping. These concepts will be compared, the combination of these two distinctly different efforts will be discussed, and eventual vehicle results presented. Most of the
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