Dynamic Axial Crush of Automotive Rail-Sized Composite Tubes: Part 2 — Tubes With Braided Reinforcements (Carbon, Kevlar®, and Glass) and Non-Plug Crush Initiators

2002 ◽  
Author(s):  
Alan L. Browne ◽  
Kristin L. Zimmerman
Keyword(s):  
Carbon Fiber ◽  
Fiber Type ◽  
Low Cost ◽  
High Volume ◽  
Woven Fabric ◽  
Composite Tubes ◽  
Fundamental Study ◽  
Axial Crush ◽  
Almost All ◽  
Tube Geometry

This paper documents the braided reinforcement portion of a successful fundamental study of the dynamic axial crush of automotive rail-sized composite tubes. Braided reinforcements were comprised principally of carbon fiber but also of Kevlar® and E-glass and combinations of the three. Fourteen different braids were used, six of which were tri-axial and the remainder bi-axial. Tubes were manufactured using Resin Transfer Molding (RTM) with processing and molding techniques that are suitable for the low cost high volume needs of the automotive industry. Braids were obtained as continuous rolls of tubular sock-like material and pulled over metal mandrels one ply at a time. Carbon fiber tow sizes ranged from 6k to 48k. Dow Derakane 470 vinylester resin was used for all tubes. Tube geometry, a 88.9×88.9 mm square cross section with 2.54 mm thick walls, approximated that of the first 500 mm of the lower rail of a typical mid-size vehicle. Note in particular that tube wall thickness was fixed at a single value in this study. A 45° bevel on the outside edge of the lead end of each tube served as the crush initiator. In total 71 dynamic axial crush tests were conducted. In terms of important findings, consistent with the woven fabric portion of this program [1], desirable dynamic axial crush response was demonstrated for RTM’d automotive rail-sized carbon fiber reinforced tubes. For almost all parameter configurations, the tubes exhibited stable and progressive crush with a reasonably flat plateau force level and an acceptable crush initiation force, i.e. one that can be withstood by the backup structure. Additionally, crush debris from such tubes was found to neither contain objectionable sharp brittle splinters nor pose a health risk. Displacement average values of dynamic axial crush force ranged from 11.88 to 26.51 kN and values of SEA (specific energy absorption) ranged between 10.42 and 22.44 kJ/kg. In terms of parameter effects, the fiber type and reinforcement architecture were found to be capable of more than doubling/halving the dynamic axial crush force and SEA.

Dynamic Axial Crush Tests of Roll Wrapped Composite Tubes: Plug vs. Non-Plug Crush Initiators

2005 ◽  
Author(s):  
Alan L. Browne ◽  
Nancy L. Johnson
Keyword(s):  
Automotive Industry ◽  
Low Cost ◽  
High Volume ◽  
Longitudinal Axis ◽  
Free Flight ◽  
Composite Tubes ◽  
Fundamental Study ◽  
Average Value ◽  
Axial Crush ◽  
Zero Radius

This paper discusses the effects of the method of crush initiation on the dynamic axial crush response of roll wrapped composite tubes. This constitutes a portion of a successful fundamental study conducted at GM R&D of the dynamic axial crush of automotive rail-sized composite tubes reinforced variously with carbon fiber, Kevlar® and hybrid combinations of the two, and manufactured using roll wrapping techniques suitable for the low cost high volume needs of the automotive industry. All tubes were manufactured using roll wrapping from multiple layers of uni-directional thermoset prepreg with the uni-directional fabric plies being oriented at ± 15° with respect to the longitudinal axis of the tube. A total of 21 dynamic axial crush tests were conducted using a free flight drop tower facility. Tests spanned a range of tube geometries — circular and square with different wall and cross section dimensions with cored and uncored walls and differing numbers of plies — and a range of drop heights/impact velocities and drop masses. A general finding was that stable and progressive crush occurred at acceptable load levels in all of the roll-wrapped tubes that were tested for all methods of crush initiation that were considered — a 45° lead end bevel either alone, with a zero radius plug-type crush initiator, or with a 12.7 mm radius plug. The method of crush initiation was, however, found to be capable of producing major differences in the crush initiation force Fp, the displacement average crush force Fav(D), the specific energy absorption SEA, and the crush morphology. As examples, both the displacement average value of dynamic axial crush force and the value of SEA were changed by as much as a factor of eight by the method of crush initiation.

scholarly journals Economics and Design Approaches for Small Commercial Turbogenerators

1997 ◽  
Author(s):  
Phillip F. Myers
Keyword(s):  
Material Selection ◽  
Low Cost ◽  
High Volume ◽  
Integrated Approach ◽  
Organizational Setting ◽  
Successful Development ◽  
Aerospace Applications ◽  
High Volume Production ◽  
Volume Production ◽  
Almost All

The successful development of small commercial turbogenerators for automotive and other applications presents a major economic challenge. Current aerospace turbogenerators in the 60 kilowatt power range sell for around $500 per kilowatt. Volume automotive turbogenerators prices must be $30 per kilowatt, or less — a 94% reduction. Turbogenerators for aerospace applications have drastically different requirements on almost all important criteria from automotive turbogenerators. The production of commercial turbogenerators requires a radically different organizational setting, mindset, and overhead structure from that necessary for the aerospace industry. Ground up designs which take an integrated approach to material selection, method of operation, fabrication techniques, supplier base, assembly methods, and low cost overheads will be necessary for commercial success. Significant innovation and simplification, and the natural effects of high volume production are also required. Success will likely require lean, agile, innovative, and specialized organizations.

High-Volume, Low-Cost Precursors for Carbon Fiber Production

2002 ◽  
Author(s):  
Carl F. Leitten ◽  
W. L. Griffith ◽  
A. L. Compere ◽  
J. T. Shaffer
Keyword(s):  
Carbon Fiber ◽  
Low Cost ◽  
High Volume ◽  
Fiber Production

scholarly journals A rapid, accurate, scalable, and portable testing system for COVID-19 diagnosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guanhua Xun ◽  
Stephan Thomas Lane ◽  
Vassily Andrew Petrov ◽  
Brandon Elliott Pepa ◽  
Huimin Zhao
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
High Volume ◽  
N Gene ◽  
Testing System ◽  
Target Sequence ◽  
One Pot ◽  
Sequence Detection ◽  
Highly Sensitive ◽  
Speed Accuracy

AbstractThe need for rapid, accurate, and scalable testing systems for COVID-19 diagnosis is clear and urgent. Here, we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It is capable of detecting the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 0.44 copies/μL and 1.09 copies/μL, respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system is used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume, low-cost access to areas in need of urgent COVID-19 testing capabilities.

Determination of transverse flexural and shear moduli of chopped carbon fiber tape-reinforced thermoplastic by vibration

2017 ◽  
Vol 52 (3) ◽  
pp. 395-404
Author(s):  
Xiuqi Lyu ◽  
Jun Takahashi ◽  
Yi Wan ◽  
Isamu Ohsawa
Keyword(s):  
Carbon Fiber ◽  
Beam Theory ◽  
Transversely Isotropic ◽  
High Volume ◽  
Bending Test ◽  
Thermoplastic Material ◽  
Shear Moduli ◽  
High Volume Production ◽  
Volume Production

Chopped carbon fiber tape-reinforced thermoplastic material is specifically developed for the high-volume production of lightweight automobiles. With excellent design processability and flexibility, the carbon fiber tape-reinforced thermoplastic material is manufactured by compressing large amounts of randomly oriented, pre-impregnated unidirectional tapes in a plane. Therefore, the carbon fiber tape-reinforced thermoplastic material presents transversely isotropic properties. Transverse shear effect along the thickness direction of carbon fiber tape-reinforced thermoplastic beam has a distinct influence on its flexural deformation. Accordingly, the Timoshenko beam theory combined with vibration frequencies was proposed to determine the set of transverse flexural and shear moduli. Meanwhile, the transverse flexural and shear moduli of carbon fiber tape-reinforced thermoplastic beam were finally determined by fitting all the first seven measured and calculated eigenfrequencies with the least squares criterion. In addition, the suggested thickness to length ratio for the 3-point bending test and Euler–Bernoulli model was given.

Effects of Accelerated Aging Period of Time at 180°C on Tensile Property of Plain Woven Fabric/Epoxy Resin Laminated Composites

2012 ◽  
Vol 182-183 ◽  
pp. 76-79 ◽  
Author(s):  
Lei Lei Song ◽  
Quan Rong Liu ◽  
Jia Lu Li
Keyword(s):  
Tensile Strength ◽  
Carbon Fiber ◽  
Epoxy Resin ◽  
Laminated Composites ◽  
Accelerated Aging ◽  
Woven Fabric ◽  
Accelerated Ageing ◽  
Time Intervals ◽  
Composite Samples

In this paper, carbon fiber reinforced resin matrix composites were produced by stacking eight pieces of carbon fiber woven plain fabric and subjected to accelerated ageing. Accelerated ageing was carried out in oven at 180°C for three different time intervals (60 hours, 120 hours and 180 hours). The influence of different ageing time intervals at 180°C on tensile properties of laminated composites was examined, compared with the composites without aging. The appearance and damage forms of these laminated composites were investigated. The results revealed that the tensile strength of the laminates declined significantly after long term accelerated aging at 180°C. The average tensile strengths of composite samples aged 60 hours, 120 hours, and 180 hours period of time at 180°C are 80.36%, 79.82%, 76.57% of average tensile strength of composite samples without aging, respectively. The high temperature accelerated aging makes the resin macromolecular structure in the composites changed, and then the adhesive force between fiber bundles and resin declines rapidly which result in the tensile strength of composites aged decrease. This research provides a useful reference for long term durability of laminated/epoxy resin composites.

Plastic Encapsulated MCM Technology for High Volume, Low Cost Electronics

Circuit World ◽  
1995 ◽  
Vol 21 (2) ◽  
pp. 28-31 ◽  
Author(s):  
R. Fillion ◽  
R. Wojnarowski ◽  
T. Gorcyzca ◽  
E. Wildi ◽  
H. Cole
Keyword(s):  
Low Cost ◽  
High Volume

The Effects of Fiber Volume Fraction on the Experiment Modal Behavior of 45°/-45° Carbon Fiber Plain Woven Fabric/Epoxy Resin Composites

2012 ◽  
Vol 583 ◽  
pp. 150-153
Author(s):  
Qian Liu ◽  
Xiao Yuan Pei ◽  
Jia Lu Li
Keyword(s):  
Carbon Fiber ◽  
Epoxy Resin ◽  
Natural Frequency ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composites ◽  
Woven Fabric ◽  
Resin Composites ◽  
Fiber Volume ◽  
Epoxy Resin Composites

The modal properties of carbon fiber woven fabric (with fiber orientation of 45°/-45°) / epoxy resin composites with different fiber volume fraction were studied by using single input and single output free vibration of cantilever beam hammering modal analysis method. The effect of different fiber volume fraction on the modal parameters of laminated composites was analyzed. The experimental results show that with the fiber volume fraction increasing, the natural frequency of laminated composites becomes larger and damping ratio becomes smaller. The fiber volume fraction smaller, the peak value of natural frequency becomes lower and the attenuating degree of acceleration amplitude becomes faster.

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