Browse Topic: Safety testing and procedures
The scope of this SAE Aerospace Information Report (AIR) is to discuss factors affecting visibility of aircraft navigation and anticollision lights, enabling those concerned with their use to have a better technical understanding of such factors, and to aid in exercising appropriate judgment in the many possible flight eventualities
ABSTRACT V-shaped hulls for vehicles, to mitigate buried blast loads, are typically formed by bending plate. Such an approach was carried out in fabricating small test articles and testing them with buried-explosive blast load in Southwest Research Institute’s (SwRI) Landmine Test Fixture. During the experiments, detailed time dependent deflections were recorded over a wide area of the test article surface using the Dynamic Deformation Instrumentation System (DDIS). This information allowed detailed comparison with numerical simulations that were performed with LS-DYNA. Though in general there is good agreement on the deflection, in the specific location of the bends in the steel the agreement decreases in the lateral cross section. Computations performed with empirical blast loads developed by SwRI and by more computationally intensive ALE methods in LS-DYNA produced the same results. Computations performed in EPIC showed the same result. The metal plate was then bent numerically so
ABSTRACT In any active safety system, it is desired to measure the “performance”. For the estimation case, generally a cost function like Mean-Square Error is used. For detection cases, the combination of Probability of Detection and Probability of False Alarm is used. Scenarios that would really expose performance measurement involve complex, dangerous and costly driving situations and are hard to recreate while having a low probability of actually being acquired . Using a virtual tool, we can produce the trials necessary to adequately determine the performance of active safety algorithms and systems. In this paper, we will outline the problem of measuring the performance of active safety algorithms or systems. We will then discuss the approach of using complex scenario design and Monte Carlo techniques to determine performance. We then follow with a brief discussion of Prescan and how it can help in this endeavor. Finally, two Monte Carlo type examples for particular active safety
ABSTRACT The Blast Event Simulations sysTem (BEST) is a synthesis tool that provides a seamless and easy-to-use coupling between existing and commercially available LS-DYNA solvers and Anthropomorphic Test Device (ATD) models for a complete sequence of explosive simulations. BEST driven simulations capture the soil/explosive/vehicle/occupant interaction. In this paper a blast simulation analysis conducted by BEST for a generic but representative vehicle is presented. The vehicle is subjected to the blast load created by an explosive buried underneath the vehicle. An ATD model is placed inside the vehicle in order to capture the loads created on the lower legs of an occupant due to the explosion. Technical details with respect to the various models engaged in the simulation are presented first. The results and the physical insight which can be gained by the analysis are discussed. A series of design modifications which add minimal weight are introduced in the vehicle structure, such as
ABSTRACT Program Executive Office (PEO) Ground Combat Systems (GCS) initiated a Green Belt project in 2007 to develop a risk management process. The Integrated Product Team (IPT) built on Defense Acquisition University (DAU) and Department of Defense (DoD) risk management guidance to create a process for risk analysis, mitigation, and rules for Risk Review Board approval. To automate this process, the IPT eventually created an Army owned, customizable tool (Risk Recon) that matched the PEO GCS process. Risk Recon is used to track risks throughout the acquisition life-cycle. Changing the culture of the PEO has been the most significant challenge. Training and follow-up of risk progress is required to keep the process from becoming stagnant. Partnership with the Original Equipment Manufacturer (OEMs)s is an integral part of all programs and a balance is needed between how the PEO and its OEMs perform risk management and communicate those risks. The software requirements continue to
An innovative new approach is presented that addresses the challenges of design in a constantly changing environment. New solutions that satisfy changing requirements are generated by rapidly reconfiguring ongoing projects and effectively reusing trusted designs. Design is essentially a process of generating knowledge about how to build new systems. Reuse is difficult because this knowledge is amorphous and difficult to access. Hierarchical platform-based engineering is used to structure and categorize this knowledge to make it easily accessible. This approach has three essential components: 1) Hierarchical platform-based design method organizes design projects into a structured library; 2) Transformational systems engineering and concurrent risk assessment are used to capture complex interactions between different CPS elements. These captured interactions help assess reusability and reconfigurability of each element; 3) A new design flow integrates platform-based design methods into
ABSTRACT Significant Design for Reliability (DfR) methodology challenges are created with the integration of autonomous vehicle technologies via applique systems in a ground military vehicle domain. Voice of the customer data indicates current passenger vehicle usage cycles are typically 5% or less (approximately 72 minutes of use in a twenty-four hour period) [2]. The time during which vehicles currently lay dormant due to drivers being otherwise occupied could change with autonomous vehicles. Within the context of the fully mature autonomous military vehicle environment, the daily vehicle usage rate could grow to 95% or more. Due to this potential increase in the duty or usage cycle of an autonomous military vehicle by an order of magnitude, several issues which impact reliability are worth exploring. Citation: M. Majcher, J. Wasiloff, “New Design for Reliability (DfR) Needs and Strategies for Emerging Autonomous Ground Vehicles”, In Proceedings of the Ground Vehicle Systems
ABSTRACT The age of large autonomous ground vehicles has arrived. Wherever vehicles are used, autonomy is desired and, in most cases, being studied and developed. The last barrier is to prove to decision makers (and the general public) that these autonomous systems are safe. This paper describes a rigorous safety testing environment for large autonomous vehicles. Our approach to this borrows elements from game theory, where multiple competing players each attempt to maximize their payout. With this construct, we can model an environment that as an agent that seeks poor performance in an effort to find the rare corner cases that can lead to automation failure
ABSTRACT Computational models are widely used in the prediction of occupant injury responses and vehicle structural performance of ground vehicles subjected to underbody blasts. Although these physics based computational models incorporate all the material and environment data, the classic models are typically deterministic and do not capture the potential variations in the design, testing and operating parameters. This paper investigates the effect of one such variation in physical tests, namely, variations in the position of occupant setup on the occupant injury responses. To study the effects of occupant position, a series of vertical drop tower tests were performed in a controlled setup. A vertical drop tower test involves an Anthropomorphic Test Device (ATD) dummy positioned on a seat and the setup is dropped on an energy attenuating surface, thus producing a desired shock pulse on the seat structure. The experimental data was analyzed for sensitivity of occupant position and ATD
ABSTRACT The study describes the development of a plug-in module of the realistic 3D Digital Human Modeling (DHM) tool RAMSIS that is used to optimize product development of military vehicle systems. The use of DHM in product development has been established for years. DHM for the development of military vehicles requires not only the representation of the vehicle occupants, but also the representation of equipment and simulation of the impact of such equipment on the Warfighter. To simulate occupants in military vehicles, whether land or air based, realistically, equipment must become an integral part of the extended human model. Simply attaching CAD-geometry to one manikin’s element is not sufficient. Equipment size needs to be scalable with respect to anthropometry, impact on joint mobility needs to be considered with respect to anatomy. Those aspects must be integrated in posture prediction algorithms to generate objective, reliable and reproducible results to help design engineers
ABSTRACT As the Army focuses to modernize existing ground vehicle fleets and develop new ground vehicle platforms, Program Managers are faced with the challenge of how to best choose a set of technologies for the vehicle that will be mature, be able to be integrated onto the platform, and have the capability to meet defined requirements. To accomplish this, the Tank Automotive Research, Development and Engineering Center (TARDEC) Systems Engineering Group (SEG) has championed the development of a methodology for executing Technical Risk Assessments, one of the components of the overall Risk Assessment. The Technical Risk Assessment activity determines critical technologies, assesses technology maturity, integration and manufacturing readiness, and identifies the associated technical risks of those critical technologies and other technologies of interest. A standardized set of criteria is being utilized by technology subject matter experts to perform the assessments, and has been used
ABSTRACT Today we have autonomous vehicles already on select road-ways and regions of this country operating in and around humans and human operated vehicles. The companies developing and testing these systems have experienced varied degrees of success and failure with regard to safe operations within this public space. There have been safety incidents that have made national headlines (when human fatalities have occurred) and their also exist a litany of other physical incidents, usually with human operated systems, that have not grabbed the headlines. Some of the select communities where these autonomous systems have been operationally tested have revoked access to their roadways (kicked out) some of these companies. As a result of these incidents recent data suggests that the public trust in autonomous vehicles is eroding [1]. This situation is couponed by the fact that there are no established safety standards, measures or technological methods to help local, state or national
Abstract: An idealized concept of a v-hull vehicle design for blast analysis has been studied in two different commercial software packages and results are compared to one another. The two software packages are different in nature: one code is an Eulerian Computational Fluid Dynamics (CFD) Finite Volume Solver while the other code is a Lagrangian Finite Element Analysis (FEA) Solver with the ability to couple structures to fluids through a special technique called Arbitrary Lagrangian Eulerian (ALE). The simulation models in this paper have been set up for both CFD and FEA using a commercial pre-processing tool to study the effect of an idealized blast on the vehicle configuration: A pressure blast charge has been placed under the center of the vehicle at the symmetry line. The charge is composed of a prescribed pressure and a temperature pulse in a medium with the properties of air. In the CFD solver, an explicit unsteady solver has been chosen for analysis purposes. This was done
ABSTRACT This paper presents Neya’s efforts in developing autonomous depot assembly and parking behaviors for the Ground Vehicle Systems Center’s (GVSC) Autonomous Ground Re-supply (AGR) program. Convoys are a prime target for the enemy, and therefore GVSC is making efforts to remove the human operators and make them autonomous. However, humans still have to manually drive multiple convoy vehicles to and from their depot parking locations before and after autonomous convoy operations – a time-consuming and laborious process. Neya systems was responsible for the design, development, and testing of the autonomous depot assembly and disassembly behaviors, enabling end-to-end autonomy for convoy operations. Our solution to the problem, including the concept of operations, design, as well as approaches towards testing and validation are described in detail
ABSTRACT Design for structural topology optimization is a method of distributing material within a design domain of prescribed dimensions. This domain is discretized into a large number of elements in which the optimization algorithm removes, adds, or maintains the amount of material. The resulting structure maximizes a prescribed mechanical performance while satisfying functional and geometric constraints. Among different topology optimization algorithms, the hybrid cellular automaton (HCA) method has proven to be efficient and robust in problems involving large, plastic deformations. The HCA method has been used to design energy absorbing structures subject to crash impact. The goal of this investigation is to extend the use of the HCA algorithm to the design of an advanced composite armor (ACA) system subject to a blast load. The ACA model utilized consists of two phases: ceramic and metallic. In this work, the proposed algorithm drives the optimal distribution of a metallic phase
Summary Combat vehicle designers have made great progress in improving crew survivability against large blast mines and improvised explosive devices. Current vehicles are very resistant to hull failure from large blasts, protecting the crew from overpressure and behind armor debris. However, the crew is still vulnerable to shock injuries arising from the blast and its after-effects. One of these injury modes is spinal compression resulting from the shock loading of the crew seat. This can be ameliorated by installing energy-absorbing seats which reduce the intensity of the spinal loading, while spreading it out over a longer time. The key question associated with energy-absorbing seats has to do with the effect of various factors associated with the design on spinal compression and injury. These include the stiffness and stroking distance of the seat’s energy absorption mechanism, the size of the blast, the vehicle shape and mass, and the weight of the seat occupant. All of these
ABSTRACT Over the course of typical survivability analyses for underbody blast events, a multitude of individual cases are examined where charge size, charge location relative to the vehicle, and vehicle clearance from the ground are varied, so as to arrive at a comprehensive assessment. While multi-physics computational tools have reduced the expense and difficulty of testing each loading case experimentally, these tools still often require significant execution and wall-clock times to perform the simulations. In efforts to greatly reduce the time required to conduct a holistic survivability analysis, Fast Running Models (FRMs) have been implemented and validated to act as a surrogate for the computationally expensive finite element tools in use today. Built using a small set of simulations, FRMs generate loading data in a matter of seconds, representing a significant improvement in survivability analysis turnaround time
ABSTRACT The automotive and defense industries are going through a period of disruption with the advent of Connected and Automated Vehicles (CAV) driven primarily by innovations in affordable sensor technologies, drive-by-wire systems, and Artificial Intelligence-based decision support systems. One of the primary tools in the testing and validation of these systems is a comparison between virtual and physical-based simulations, which provides a low-cost, systems-approach testing of frequently occurring driving scenarios such as vehicle platooning and edge cases and sensor-spoofing in congested areas. Consequently, the project team developed a robotic vehicle platform—Scaled Testbed for Automated and Robotic Systems (STARS)—to be used for accelerated testing elements of Automated Driving Systems (ADS) including data acquisition through sensor-fusion practices typically observed in the field of robotics. This paper will highlight the implementation of STARS as a scaled testbed for rapid
ABSTRACT The objective of this paper is to provide guidance on what to consider to implement Risk Management within an organization including what practices need to be in place to ensure that leadership will continue to support Risk Management over the long term. It also presents techniques to determine risk severity, risk mitigation methods, ideas for ensuring risk management helps achieve a program’s objectives, and techniques for incorporating risk measurement parameters into a program’s daily execution activities
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