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Bicycle Braking Performance Testing and Analysis

Momentum Engineering Corp.-Nicholas Famiglietti, Benjamin Nguyen, Edward Fatzinger, Jon Landerville
  • Technical Paper
  • 2020-01-0876
To be published on 2020-04-14 by SAE International in United States
The goal of this study was to determine the braking capabilities of different bicycle types, with different brake setups and applications. A variety of bicycles, including a mountain bike, beach cruiser, BMX bike, road bike, and commuter bike were used to perform brake-to-stop tests. Prior to brake testing, the bicycles were fully inspected, prepped, and documented. Details of the bicycles’ make, model, tires, wheels, brake setup, suspension setup, and preexisting damage were photographed and recorded. The standardized brake testing procedure consisted of rear only brake application and both front and rear brake application. In order to maintain brake application consistency, a single rider performed all series of the skid/brake tests at the same location, on dry asphalt. The tests were performed at an initial velocity of 9 – 20 mph. For each test, the rider accelerated to the test speed and applied maximum braking effort while maintaining a natural upright position to reduce lean. The tests were performed on a painted grid for visibility purposed in measuring skid lengths and post-test video analysis. The bicycle…
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Road Curvature Decomposition for Autonomous Guidance

University of Nebraska-Lincoln-Ricardo Jacome, Cody Stolle, Michael Sweigard
  • Technical Paper
  • 2020-01-1024
To be published on 2020-04-14 by SAE International in United States
Vehicle autonomy is critically dependent on an accurate identification and mathematical representation of road and lane geometries. Many road lane identification systems are ad hoc (e.g., machine vision and lane keeping systems) or utilize finely-discretized path data and vehicle tracking systems such as GPS. A novel Midwest Discrete Curvature (MDC) method is proposed in which geodetic road data is parsed along road directions and digitally stored in a road data matrix. Road data is discretized to geospatial points and curvature and road tangent vectorization, which can be utilized to generate consistent, mathematically-defined road profiles with deterministic boundary conditions, consistent non-holonomic boundary constraints, and a smooth, differentiable path which connects critical road coordinates. The method was evaluated by discretizing three road segments: a hypothetical road consistent with the American Association of State Highway and Transportation Officials (AASHTO) Green Book design standards, a road segment discretized using satellite photography and GPS data points, and an in-vehicle GPS trace collected at 10 Hz. Improvements and further research were recommended to expand findings, but results indicated potential for implementation…

New Method Detects Defects in 2D Materials

  • Magazine Article
  • TBMG-36248
Published 2020-03-01 by Tech Briefs Media Group in United States

Researchers have developed a technique to quickly and sensitively characterize defects in 2D materials used in sensors and electronics. Their solution is to use laser light combined with a phenomenon called second harmonic generation, in which the frequency of the light shone on the material reflects at double the original frequency. Add to this a technique called dark field imaging, in which extraneous light is filtered out so that defects shine through.

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Thread Inspection Practices

E-25 General Standards for Aerospace and Propulsion Systems
  • Aerospace Standard
  • AS5870
  • Current
Published 2020-02-03 by SAE International in United States
This document addresses AS8879 thread inspection issues relating to selection, usage and capability of gages. It addresses the selection of calibrated measurement gages, the need for defined quality metrics, the methodology of determining the appropriate guardband factors, and the minimum inspection requirements for single element pitch diameter gages. Users of this document shall apply the information described herein for the evaluation of the capability of their measurements based on the measurement consumer risk. It involves the analysis of the measurement (product) distribution and biases of both the product and measurement system distributions. It protects the consumer from the worst case distribution results. A whitepaper has been developed to provide supporting documentation and the rationale used in the development of this standard. This whitepaper will be published by the SAE as an Aerospace Information Report (AIR6553). This document recommends the use of ASME B1.2 “Gages and Gaging for Unified Inch Screw Threads” or IFI 301 “Gage Calibration Requirements and Procedures for Thread Gages” as guides for establishing the minimum calibration requirements for all types of thread…
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Flexure for Self-Assembly

  • Magazine Article
  • TBMG-35998
Published 2020-02-01 by Tech Briefs Media Group in United States

Conventional fastening mechanisms like nails, bolts, and welds are subject to manufacturing and inspection tolerances, differential thermal growth, and other sources of error that lead to over-constraint, among other challenges, for manufacturers and assemblers. Sandia researchers have developed a versatile flexure design that resolves common issues such as over-constraint while providing more sophisticated control of freedom of movement, stiffness, configuration, and constraint and compliance features. This level of control and versatility is valuable in advanced or self-assembling manufacturing settings, particularly for large or complex systems.

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O-Ring Machined from AMS3617 Material

A-6C2 Seals Committee
  • Aerospace Standard
  • AS9772A
  • Current
Published 2020-01-13 by SAE International in United States
This standard establishes the dimensional and visual quality requirements, lot requirements, and packaging and labeling requirements for O-rings machined from AMS3617 polyamide material. It shall be used for procurement purposes.
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Dynamic Mechanical Strain-Induced Temperature Gradient Coating

  • Magazine Article
  • TBMG-35811
Published 2020-01-01 by Tech Briefs Media Group in United States

Evaluating components for discontinuities without damaging the part or system remains a priority for diverse industries and research fields. Low-cost techniques such as fluorescent penetrant inspection (FPI) are used widely by major industries, such as aviation and aerospace, despite limited defect detection and the need for complex, multi-step operations in highly controlled conditions. Nondestructive methods such as sonic infrared (SIR) testing apply ultrasound waves to identify surface defects and cracks. These techniques hold promise for widespread use but stand to improve in the detection of false positives.

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Unsettled Technology Domains in Aerospace Additive Manufacturing Concerning Safety, Airworthiness, and Certification

Muelaner Engineering, Ltd.-Jody Muelaner
  • Research Report
  • EPR2019008
Published 2019-12-23 by SAE International in United States
Additive manufacturing (AM) is currently being used to produce many certified aerospace components. However, significant advantages of AM are not exploited due to unresolved issues associated with process control, feedstock materials, surface finish, inspection, and cost. Components subject to fatigue must undergo surface finish improvements to enable inspection. This adds cost and limits the use of topology optimization. Continued development of process models is also required to enable optimization and understand the potential for defects in thin-walled and slender sections. Costs are high for powder-fed processes due to material costs, machine costs, and low deposition rates. Costs for wire-fed processes are high due to the extensive postprocess machining required. In addition, these processes are limited to low-complexity features. Incremental improvements in all of these areas are being made, but a step change could potentially be achieved by hybrid processes, which use wire feedstock to deposit the bulk of the part and powder for fine detail.NOTE: SAE EDGE™ Research Reports are intended to identify and illuminate key issues in emerging, but still unsettled, technologies of interest…
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Fundamentals of GD&T 2018 3-day

  • Professional Development
  • ET1920024
Published 2019-12-03

This course teaches the terms, rules, symbols, and concepts of GD&T as prescribed in the ASME Y14.5-2018 Standard.

This course offers an in-depth explanation of geometric tolerancing symbols, their tolerance zones, applicable modifiers, common applications, and verification principles. The class includes a comparison of GD&T to the directly toleranced dimensioning method; Rules #1 and #2; form and orientation controls; tolerance of position; runout and profile controls. Newly acquired learning is reinforced throughout the class with more than 150 practice problems.  

Each attendee receives a Fundamentals of Geometric Dimensioning and Tolerancing 2018,  Using Critical Thinking Skills textbook by Alex Krulikowski (Based on the ASME Y14.5-2018)

Students who attend courses like this one walk away with more than knowledge - they gain on-the-job skills because the learning materials are performance-based and taught by industry professionals.

MMOD Impact Detection and Location

  • Magazine Article
  • TBMG-35686
Published 2019-12-01 by Tech Briefs Media Group in United States

Determination of micrometeoroid/ orbital debris (MMOD) impact on orbiting spacecraft currently requires visual inspection. For human-rated spacecraft such as the International Space Station (ISS) and previously, the Space Shuttle Orbiter, this has required crew time as well as vehicle assets to identify damage due to MMOD strikes. For unmanned spacecraft, there are no human assets present to conduct detailed surveys to ascertain potential damage.