bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional Models With Inherent Behavior: Towards a Framework for Safety Analysis Early in the Design of Complex Systems
Authors: McIntire Matthew G. , Keshavarzi Elham , Tumer Irem Y. , Hoyle Christopher 
Published: February 2017

This paper represents a step toward a more complete frame-work of safety analysis early in the design process, specifically during functional modeling. This would be especially useful when designing in a new domain, where many functions have yet to be solved, or for a problem where the functional architecture space is large. In order to effectively analyze the inherent safety of a design only described by its functions and flows, we require some way to simulate it.
As an already-available function failure reasoning tool, Function Failure Identification and Propagation (FFIP) utilizes two distinct system models: a behavioral model, and a functional model. The behavioral model simulates system component behavior, and FFIP maps specific component behaviors to functions in the functional model. We have created a new function-failure reasoning method which generalizes failure behavior directly to functions, by which the engineer can create functional models to simulate the functional failure propagations a system may experience early in the design process without a separate behavioral model.
We give each basis-defined function-flow element a pre-defined behavior consisting of nominal and failure operational modes, and the resultant effect each mode has on its functions connected flows. Flows are represented by a two-variable object reminiscent of a bond from bond graphs: the state of each flow is represented by an effort variable and a flow-rate variable. The functional model may be thought of as a bond graph where each functional element is a state machine. Users can quickly describe functional models with consistent behavior by constructing their models as Python NetworkX graph objects, so that they may quickly model multiple functional architectures of their proposed system. We are implementing the method in Python to be used in conjunction with other function-failure analysis tools.
We also introduce a new method for the inclusion of time in a state machine model, so that dynamic systems may be modeled as fast-evaluating state machines. State machines have no inherent representation of time, while physics-based models simulate along repetitive time steps. We use a more middle-ground pseudo time approach. State transitions may impose a time delay once all of their connected flow conditions are met. Once the entire system model has reached steady state in a timeless sense, the clock is advanced all at once to the first time at which a reported delay is ended. Simulation then resumes in the timeless sense.
We seek to demonstrate this modeling method on an electrical power system functional model used in previous FFIP studies, in order to compare the failure scenario results of an exhaustive fault combination experiment with similar results using the FFIP method.
Location Sensor Fusion and Error Correction in Intelligent Vehicles
Authors: Beyerl Thomas , Ibru Bernard , Williams Johnnie , Augusma Imani , Soloiu Valentin 
Published: February 2017

Autonomous vehicles provide an opportunity to reduce highway congestion and emissions, while increasing highway safety. Intelligently routed vehicles will also be better integrated with existing traffic patterns, minimizing travel times. By reducing the time wasted in traffic; harmful emissions will consummately be reduced. Well-designed autonomous control systems provide for increased highway safety by reducing the frequency and severity of traffic accidents caused by driver error. In order to achieve this, a robust multi-layered control system must be designed, which minimizes the likelihood of computer error, while enabling seamless transition to and from human control.
Autonomous vehicle navigation systems rely on accurate and timely sensor inputs to determine a vehicle’s location, attitude, speed, and acceleration. This paper describes a telemetry sensor fusion approach, which enables an autonomous vehicle to navigate, complex intersections, based on previously planned paths and near field sensors. This reduces computational overhead on the vehicle’s computer, and provides real time redundancy for system errors or delays. In conjunction with a full complement of environmental sensors, this path planning - path following approach enhances the robustness of autonomous vehicle operating models.
This research supports the rapidly expanding field of autonomous automobiles by examining novel concepts for robust telemetry sensor fusion between inertial, GPS, and wheel speed sensors, which allows for error correction and enhanced positional accuracy, when compared to conventional navigation algorithms.
Deterministic Hazard Evaluation for Natural Gas Pipes Failure
Authors: Pourgol Mohammad Mohammad , Mehrzad Arash , Soleimani Morteza 
Published: February 2017

Gas stations and distribution facilities in a city districts may result in accidents resulting injuries to people living in these districts. The exposure to released toxic materials is another hazard in gas pipes accidents. Therefore, the gas pipe lines demand special attention for the risk assessment.
In this study, the gas pipe rupture is evaluated on accident scenarios. Fire concentration range has been analyzed for different scenarios for cold and hot weather conditions. Furthermore, the length of flame has been simulated based on releasing flammable materials with governed equations. For modeling, PHAST software is utilized for simulation of released material in environment by considering the atmosphere conditions. Sensitivity analysis is done by 10% increasing in important parameter of problem. As a case study, a gas station is used for assessment. Furthermore, the results are verified with some published studies.
A Method of Fracture Toughness Measurement and Effect of Partial Annealing on Monolithic Thick Cold Sprayed Aluminum 6061 Deposits
Authors: Bangstein B. , Ellingsen M. , Scholl N. 
Published: February 2017

Cold spray is a solid-state material deposition method that can create thick (>10mm) metal layers that adhere metallurgically to a base part or a substrate. Numerous potential applications exist, such as returning worn mechanical parts to their original dimension, extending their service life.
For fatigue applications the fracture properties of cold spray deposited material must be known but little to no literature has been found on the fracture behavior of cold spray deposited material alone, which prompted the study presented here.
Fracture toughness specimens were manufactured by depositing thick cold-sprayed layers of powdered aluminum 6061 onto an aluminum 6061 substrate using N2 as the carrier gas. The substrate was then machined away, and monolithic miniature compact tension fracture toughness specimens were machined from the cold spray deposit itself, following ASTM E-1820.
The fracture behavior of the cold sprayed material was then experimentally determined using the elastic-plastic J-resistance method for compact test specimens described in ASTM E-1820. Two specimen conditions were successfully tested, “as-sprayed” and “partially annealed”.
The results are that the Mode-I elastic-plastic stress intensity factor JI has been successfully measured for cold-spray deposited material alone, and that partially annealing a cold-spray deposit can dramatically increase its fracture toughness.
Exergy Analysis of a Novel Cryogenic Concept for the Liquefaction of Natural Gas Integrated Into an Air Separation Process
Authors: Tesch S. , Morosuk T. , Tsatsaronis G. 
Published: February 2017

The increasing demand for primary energy leads to a growing market of natural gas and the associated market for liquefied natural gas (LNG) increases, too. The liquefaction of natural gas is an energy- and cost-intensive process. After exploration, natural gas, is pretreated and cooled to the liquefaction temperature of around −160°C.
In this paper, a novel concept for the integration of the liquefaction of natural gas into an air separation process is introduced. The system is evaluated from the energetic and exergetic points of view. Additionally, an advanced exergy analysis is conducted. The analysis of the concepts shows the effect of important parameters regarding the maximum amount of liquefiable of natural gas and the total power consumption. Comparing the different cases, the amount of LNG production could be increased by two thirds, while the power consumption is doubled. The results of the exergy analysis show, that the introduction of the liquefaction of natural gas has a positive effect on the exergetic efficiency of a convetional air separation unit, which increases from 38% to 49%.
Conventional Locomotive Coupling Tests
Authors: Llana Patricia , Jacobsen Karina , Tyrell David 
Published: February 2017

Research to develop new technologies for increasing the safety of passengers and crew in rail equipment is being directed by the Federal Railroad Administration’s (FRA’s) Office of Research, Development, and Technology. Crash energy management (CEM) components which can be integrated into the end structure of a locomotive have been developed: a push-back coupler and a deformable anti-climber. These components are designed to inhibit override in the event of a collision. The results of vehicle-to-vehicle override, where the strong underframe of one vehicle, typically a locomotive, impacts the weaker superstructure of the other vehicle, can be devastating. These components are designed to improve crashworthiness for equipped locomotives in a wide range of potential collisions, including collisions with conventional locomotives, conventional cab cars, and freight equipment.
Concerns have been raised in discussions with industry that push-back couplers may trigger prematurely, and may require replacement due to unintentional activation as a result of service loads. Push-back couplers are designed with trigger loads meant to exceed the expected maximum service loads experienced by conventional couplers. Analytical models are typically used to determine these required trigger loads. Two sets of coupling tests are planned to demonstrate this, one with a conventional locomotive equipped with conventional draft gear and coupler, and another with a conventional locomotive equipped with a push-back coupler. These tests will allow a performance comparison of a conventional locomotive with a CEM-equipped locomotive during coupling. In addition to the two sets of coupling tests, car-to-car compatibility tests of CEM-equipped locomotives, as well as a train-to-train test are also planned. This arrangement of tests allows for evaluation of the CEM-equipped locomotive performance, as well as comparison of measured with simulated locomotive performance in the car-to-car and train-to-train tests.
This paper describes the results of the coupling tests of conventional equipment. In this set of tests, a moving locomotive was coupled to a standing cab car. The coupling speed for the first test was 2 mph, the second test 4 mph, and the tests continued with the speed incrementing by 2 mph until the last test was conducted at 12 mph. The damage observed resulting from the coupling tests is described. The lowest coupling speed at which damage occurred was 6 mph. Prior to the tests, a one-dimensional lumped-mass model was developed for predicting the longitudinal forces acting on the equipment and couplers. The model predicted that damage would occur for coupling speeds between 6 and 8 mph. The results of these conventional coupling tests compare favorably with pre-test predictions. Next steps in the research program, including future full-scale dynamic tests, are discussed.
Thermal Performance of a Fin Operating Under Dehumidifying Operating Conditions
Authors: Pashah Sulaman 
Published: February 2017

The use of extended surfaces or fins is very common for enhancing the heat transfer between a prime surfaces and surrounding environment. The applications cover both scenarios where the prime surface is either at a higher or at a lower temperature than the surrounding environment. In the first case, only sensible heat transfer occurs whereas the latter is typical for refrigeration and air conditioning applications where both sensible and latent heat transfer occur.
The performance of a fin is well described through a dimensionless parameter called fin efficiency. The efficiency is represented graphically in form of charts as a function of another dimensionless parameter called the fin parameter. The objective of the dimensionless presentation is that it provides the solution to a class of problems. However, this is true only for the dry fins because such charts for wet fins are for a set of particular operating conditions (i.e. temperature and psychrometric data). Thus, a separate chart is required if operating conditions are changed. The objective of present study is to investigate the possibility of developing the fin efficiency charts in the form which are independent of the operating conditions, thus a single chart covering all possible operating conditions. The finite element formulation is used to account for the actual nonlinear psychrometric relationships.
Tuning and Implementation of a Feedback Control Strategy for Drying Process Based on IAE Minimization
Authors: Lugo Ana M. , Audivet Durán Cinthia , Sanjuán Marco E. 
Published: February 2017

Agricultural products contain a significant amount of moisture during the harvesting stage. The presence of this moisture increases the deterioration rate of the products during storage, handling, and processing periods; drying is one of the most suitable processes that can be applied to these by-products before using them as cattle feed or soil conditioner. This process is certainly one of the most energy consuming found in industry. The selection of an appropriate process control strategies can minimize production and maintenance cost, maximize product quality and reduce environmental pollution. Rotary dryers are normally employed to dry agricultural products because it can give high production rate and high drying uniformity.
The aim of this research is to improve the performance of a feedback control strategy for a drying process, based on the implementation design of experiment; this approach allows finding specifics tuning parameters and potential operation conditions that will traduce in a more robust process. The selected criterion to evaluate the performance of the strategy is the integral absolute of the error (IAE) and the analysis is based on a dynamic model of a rotary dryer. The objective of the process improvement is to find an operation region, function of the controller gain, the integral time and derivative time, in which IAE parameter is minimized, this will lead to enhancement of equipment performance and reduction of the wear of the final control element. Once the controlled strategy is described, the methodology states an exploratory stage, for process characterization, establishment of a regression model, to describe the relation between experiment significant factors and response variable, maximum ascent route, exploration of a possible curvature, definition of a new regression model and finally determination of a new optimum operating point.
Static and Dynamic Pull-In of Electrically Actuated Circular Micro-Membranes
Authors: Sajadi Banafsheh , Alijani Farbod , Goosen Hans , van Keulen Fred 
Published: February 2017

Micro-Electro-Mechanical devices have shown enormous popularity in engineering devices as sensors and actuators. In this paper, the instability, i.e. the dynamic pull-in behavior, of an electrically actuated circular micro-membrane is studied. In order to investigate the periodic solutions, detect bifurcations and follow branches of the solution, the non-linear equation of motion is derived using an energy approach, and, is solved by using a pseudo arc-length continuation and collocation technique. It has been shown that, both hardening and/or softening nonlinear responses could emerge depending on the applied DC voltage. The results indicate that the critical load parameters, namely DC and AC voltages and the excitation frequency, have a major influence on the pull-in characteristics of the micro-membrane. The results reveal different dynamic pull-in mechanisms. In addition, they accurately show the decrease of the pull-in voltage due to dynamic loading.
The proposed approximate solution is very fast and robust for detecting the pull-in instability. It allows observation of both global and local softening behavior even close to dynamic pullin, where the resonance frequency is almost equal to zero.
Investigation of Heavy Truck Restraint System Effectiveness Through Finite Element Computer Simulations in Frontal Crashes
Authors: Schulz Nathan , Silvestri Dobrovolny Chiara , Mohanakrishnan Abhinav 
Published: February 2017

Computer finite element simulations play an important role in reducing the cost and time taken for prediction of a crash scenario. While interior crash protection has received adequate attention for automobiles, very little is known for commercial vehicle such as heavy trucks. The understanding of injury types for heavy trucks occupants in relation to different crash scenarios would help mitigation of the injury severity.
Finite element computer models of the heavy truck cabin structure, interior cabin components, anthropomorphic test device (ATD) (also called dummy) and passive restraint systems were developed and assembled to simulate head-on crash of a heavy truck into a rigid barrier. The researchers developed a computer simulation parametric evaluation with respect to specific seat belt restraint system parameters for a speed impact of 56.3 km/h (35 mph). Restraint parameter variations within this research study are seat belt load limiting characteristics, inclusion of seat belt pretensioner, and variation of seat belt D-ring location. Additionally an airbag was included to investigate another restraint system. For each simulated impact characteristic and restraint system variation, the occupant kinematics were observed and occupant risks were assessed.
Within the approximations and assumptions included in this study, the results presented in this paper should be considered as preliminary guidance on the effectiveness of the use of seat belt as occupant injury mitigation system.
Combat Helmet Design Incorporating Multiple Ballistic Threats, Brain Functional Areas and Injury Considerations
Authors: Matic Peter , Moser Alex E. , Saunders Robert N. 
Published: February 2017

Combat helmet protection zone parametric design is presented for small arms and explosive device ballistic threat notional spatial distributions. The analysis is conducted using a computer aided design software application developed to evaluate ballistic threats, helmet design parameters, and a standard set of common brain injuries associated with head impacts. The analysis helps to define the helmet trade space, facilitates prototyping, and supports helmet design optimization.
Direct head impacts and helmet impacts, with and without helmet back face contact to the head, are tabulated. Head strikes are assumed to produce critical or fatal penetrating injuries. Helmet back face deflections and impact generated projectile-helmet-head motions are determined. Helmet impact obliquity is accounted for by attenuating back face deflection. Head injury estimates for ten common focal and diffuse head injuries are determined from the back face deflections and the head injury criteria. These, in turn, are related to the abbreviated injury score and associated radiographic dimensional diagnostic criteria and loss of consciousness diagnostic criteria from the trauma literature.
Thermal Predictions of the AGR-3/4 Experiment Using PIE-Measured Time Varying Gas Gaps
Authors: Hawkes Grant L. , Sterbentz James W. , Maki John T. , Pham Binh T. 
Published: February 2017

A thermal analysis was performed for the Advanced Gas Reactor test experiment (AGR-3/4) with Post Irradiation Examination (PIE) measured time varying gas gaps. The experiment was irradiated at the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). Several fuel irradiation experiments are planned for the AGR Fuel Development and Qualification Program which supports the development of the Very-High-Temperature gas-cooled Reactor (VHTR) under the Next-Generation Nuclear Plant (NGNP) project.
AGR-3/4 combines two tests in a series of planned AGR experiments to test tri-structural-isotropic (TRISO)-coated, low-enriched uranium oxy-carbide fuel. The AGR-3/4 test was designed primarily to assess fission product transport through various graphite materials. The AGR-3/4 test irradiation in the ATR started in December 2011 and finished in April 2014. Forty-eight (48) TRISO fueled compacts were inserted into twelve separate capsules for the experiment (four compacts per capsule).
The purpose of this analysis was to calculate the temperatures of each compact and graphite layer to obtain daily average temperatures using PIE-measured time (fast neutron fluence) varying gas gaps and to compare with experimentally measured thermocouple data. PIE-measured experimental data was used for the graphite shrinkage versus fast neutron fluence. Heat rates were input from a detailed physics analysis using the Monte Carlo N-Particle (MCNP) code for each day during the experiment. Individual heat rates for each non-fuel component were input as well. A steady-state thermal analysis was performed for each daily calculation. A finite element model was created for each capsule using the commercial finite element heat transfer and stress analysis package ABAQUS. The fission and neutron gamma heat rates were calculated with the nuclear physics code MCNP. ATR outer shim control cylinders and neck shim rods along with driver fuel power and fuel depletion were incorporated into the daily physics heat rate calculations. Compact and graphite thermal conductivity were input as a function of temperature and fast neutron fluence with the field variable option in ABAQUS. Surface-to-surface radiation heat transfer along with conduction heat transfer through the gas mixture of helium-neon (used for temperature control) was used in these models. Model results are compared to thermocouple data taken during the experiment.