Tire ABS-Braking Prediction with Lab Tests and Friction Simulations

2015 ◽  
Vol 43 (4) ◽  
pp. 260-275 ◽  
Author(s):  
Pavel A. Ignatyev ◽  
Stefan Ripka ◽  
Norbert Mueller ◽  
Stefan Torbruegge ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
High Speed ◽  
High Performance ◽  
Viscous Friction ◽  
Optimal Level ◽  
Friction Test ◽  
Test Procedures ◽  
Braking Performance ◽  
Friction Measurements ◽  
Braking Process

ABSTRACT The invention and application of antilock braking systems (ABS) has resulted in a significant improvement of traffic safety and a reduction of stopping distance, especially on wet roads [1]. The reason for this success is rather clear: ABS is designed to steer the braking process in the most efficient way by keeping an optimal level of tire slip. At the same time, it must be clear that ABS uses braking forces generated in the tire footprint, and really good braking is possible only with high-performance tires. The best way to probe tire performance is to build tires and test them. This is, however, a long and an expensive procedure, so prediction of ABS performance based on results of some simple experiments is a very attractive supplement to the development process. Tire-braking performance is related to the friction of rubber on a surface. Relevant friction mechanisms can include adhesion, rubber hysteresis, and various kinds of viscous friction. All of these phenomena depend on the local sliding velocity, load, and temperature of tread rubber. Tire blocks pass the footprint area of a braking tire very rapidly, but their dynamics are indeed influenced by ABS. All of these aspects make the problem of ABS-braking prediction very intricate. In this publication, we present an approach for prediction of the ABS-braking performance. The approach links friction measurements conducted in laboratory to tire tests results. The friction of six specially designed compounds was measured on dry and wet surfaces using a high-speed linear friction test rig. Obtained experimental results are analyzed with the aid of rubber friction theory [2,3] involving both surface and rubber as input parameters. It is demonstrated that lab friction test procedures can be used for prediction of ABS wet braking performance.

scholarly journals High Performance Valve Seat Materials for CNG Powered Combustion Engines

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4860
Author(s):  
Andrzej Romański ◽  
Elżbieta Cygan-Bączek
Keyword(s):  
High Speed ◽  
High Performance ◽  
Base Material ◽  
High Speed Steel ◽  
Wear Test ◽  
Gas Temperature ◽  
Valve Seat ◽  
Test Procedures ◽  
Gasoline Engines ◽  
Engine Valves

The conventional copper infiltrated high speed steel (HSS) valve seats used in gasoline engines are not suitable for CNG combustion because the exhaust gas temperature is at least 80 °C higher, which drastically shortens the service life of the engine valves. Therefore, a proprietary high-alloy HSS-base material was designed to combat hot corrosion and mechanical wear of valve seat faces in CNG fuelled engines. A batch of −100 mesh water atomized HSS powder was commissioned. The powder was vacuum annealed in order to reduce oxygen content and increase its compressibility. To improve the final part machinability, 1.2% MnS was admixed to the HSS powder prior to compaction. The green compacts were sintered at 1135 °C in nitrogen to around 83% TD and subsequently infiltrated with a copper alloy. After installing the valve seat components on a cylinder head, the engine was tested for 100 h according to the automotive industry valve seat wear test procedures. Both the periodic 8-h checks as well as the final examination of the valve seats showed very slow wear, indicating their suitability for CNG powered engines.

A Power Flow Model for High Speed Motorized Spindles—Heat Generation Characterization

2000 ◽  
Vol 123 (3) ◽  
pp. 494-505 ◽  
Author(s):  
Bernd Bossmanns ◽  
Jay F. Tu
Keyword(s):  
Power Distribution ◽  
High Speed ◽  
High Performance ◽  
Power Flow ◽  
Flow Model ◽  
Maximum Speed ◽  
Motorized Spindle ◽  
Test Procedures ◽  
Source Models ◽  
Motorized Spindles

Lack of a more complete understanding of system characteristics, particularly thermal effects, severely limits the reliability of high speed spindles to support manufacturing. High speed spindles are notorious for their sudden catastrophic failures without alarming signs at high speeds due to thermal problems. In this paper, a qualitative power flow model is presented to characterize the power distribution of a high speed motorized spindle. Quantitative heat source models of the built-in motor and the bearings are then developed. These models are verified with a custom-built high performance motorized spindle of 32 KW and a maximum speed of 25,000 rpm (1.5 million DN). Several systematic test procedures are also developed to validate the models.

Effect of Matrix Alloying on Braking Performance of Copper-Based Brake Pad Under Continuous Emergency Braking

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Peng Zhang ◽  
Lin Zhang ◽  
Dongbin Wei ◽  
Xuanhui Qu
Keyword(s):  
Friction Coefficient ◽  
Friction Surface ◽  
High Speed ◽  
High Strength ◽  
Brake Pad ◽  
Braking Performance ◽  
Emergency Braking ◽  
Ni Content ◽  
Improved Stability ◽  
Braking Process

Abstract The continuous emergency braking performance of copper-based brake pads alloyed with different Ni contents were tested. The results showed that the copper-based brake pad with high Ni content exhibits improved stability of friction coefficient during the whole emergency braking process, which indicates that Ni helps to reduce the sensitivity of the brake pad to the change of braking conditions. Moreover, the fade phenomenon of friction coefficient is obviously alleviated as the increase in Ni content under high-pressure and high-speed braking conditions. The introduction of Ni enhances the plastic deformation resistance of friction surface and promotes the formation of high-strength mechanical mixed layer and thick tribo-oxide film. This stable tribo-film remained on the contact interface is responsible for the steady mean friction coefficient under different braking conditions. Excessive addition of Ni reduces the plasticity of the friction surface, leading to the change of the main wear mechanism from adhesive wear to delamination

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

PHAX-SCAN: Functional integration of a Scanning Electron Microscope and an energy-dispersive x-ray analyser

1989 ◽  
Vol 47 ◽  
pp. 56-57
Author(s):  
Marc H. Peeters ◽  
Max T. Otten
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
Functional Integration ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray ◽  
High Speed Analysis ◽  
Scanning Electron

Over the past decades, the combination of energy-dispersive analysis of X-rays and scanning electron microscopy has proved to be a powerful tool for fast and reliable elemental characterization of a large variety of specimens. The technique has evolved rapidly from a purely qualitative characterization method to a reliable quantitative way of analysis. In the last 5 years, an increasing need for automation is observed, whereby energy-dispersive analysers control the beam and stage movement of the scanning electron microscope in order to collect digital X-ray images and perform unattended point analysis over multiple locations.The Philips High-speed Analysis of X-rays system (PHAX-Scan) makes use of the high performance dual-processor structure of the EDAX PV9900 analyser and the databus structure of the Philips series 500 scanning electron microscope to provide a highly automated, user-friendly and extremely fast microanalysis system. The software that runs on the hardware described above was specifically designed to provide the ultimate attainable speed on the system.

The bright future of digital imaging in scanning electron microscopy

1993 ◽  
Vol 51 ◽  
pp. 768-769
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Digital Imaging ◽  
High Speed ◽  
High Performance ◽  
Mass Storage ◽  
Analog To Digital ◽  
Central Processing ◽  
Digital Imaging Technology ◽  
Scanning Electron

One of the major advancements applied to scanning electron microscopy (SEM) during the past 10 years has been the development and application of digital imaging technology. Advancements in technology, notably the availability of less expensive, high-density memory chips and the development of high speed analog-to-digital converters, mass storage and high performance central processing units have fostered this revolution. Today, most modern SEM instruments have digital electronics as a standard feature. These instruments, generally have 8 bit or 256 gray levels with, at least, 512 × 512 pixel density operating at TV rate. In addition, current slow-scan commercial frame-grabber cards, directly applicable to the SEM, can have upwards of 12-14 bit lateral resolution permitting image acquisition at 4096 × 4096 resolution or greater. The two major categories of SEM systems to which digital technology have been applied are:In the analog SEM system the scan generator is normally operated in an analog manner and the image is displayed in an analog or "slow scan" mode.

Performance Analysis of Various Multipliers Using 8T-full Adder with 180nm Technology

2020 ◽  
Vol 13 (6) ◽  
pp. 864-870
Author(s):  
Sai Venkatramana Prasada G.S ◽  
G. Seshikala ◽  
S. Niranjana
Keyword(s):  
Low Power ◽  
Power Dissipation ◽  
High Speed ◽  
High Performance ◽  
Full Adder ◽  
Fundamental Operation ◽  
Wallace Tree ◽  
Power Delay Product ◽  
The Comparative Study ◽  
Wallace Tree Multiplier

Background: This paper presents the comparative study of power dissipation, delay and power delay product (PDP) of different full adders and multiplier designs. Methods: Full adder is the fundamental operation for any processors, DSP architectures and VLSI systems. Here ten different full adder structures were analyzed for their best performance using a Mentor Graphics tool with 180nm technology. Results: From the analysis result high performance full adder is extracted for further higher level designs. 8T full adder exhibits high speed, low power delay and low power delay product and hence it is considered to construct four different multiplier designs, such as Array multiplier, Baugh Wooley multiplier, Braun multiplier and Wallace Tree multiplier. These different structures of multipliers were designed using 8T full adder and simulated using Mentor Graphics tool in a constant W/L aspect ratio. Conclusion: From the analysis, it is concluded that Wallace Tree multiplier is the high speed multiplier but dissipates comparatively high power. Baugh Wooley multiplier dissipates less power but exhibits more time delay and low PDP.

scholarly journals Ultracompact and low-power-consumption silicon thermo-optic switch for high-speed data

Nanophotonics ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 937-945
Author(s):  
Ruihuan Zhang ◽  
Yu He ◽  
Yong Zhang ◽  
Shaohua An ◽  
Qingming Zhu ◽  
...  
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
High Speed ◽  
High Performance ◽  
Pulse Amplitude ◽  
Telecommunication Networks ◽  
Low Power Consumption ◽  
Power Efficient ◽  
High Speed Data ◽  
On Chip

AbstractUltracompact and low-power-consumption optical switches are desired for high-performance telecommunication networks and data centers. Here, we demonstrate an on-chip power-efficient 2 × 2 thermo-optic switch unit by using a suspended photonic crystal nanobeam structure. A submilliwatt switching power of 0.15 mW is obtained with a tuning efficiency of 7.71 nm/mW in a compact footprint of 60 μm × 16 μm. The bandwidth of the switch is properly designed for a four-level pulse amplitude modulation signal with a 124 Gb/s raw data rate. To the best of our knowledge, the proposed switch is the most power-efficient resonator-based thermo-optic switch unit with the highest tuning efficiency and data ever reported.

scholarly journals High-Speed 3D Printing of High-Performance Thermosetting Polymers via Two-Stage Curing

2018 ◽  
Vol 39 (7) ◽  
pp. 1700809 ◽  
Author(s):  
Xiao Kuang ◽  
Zeang Zhao ◽  
Kaijuan Chen ◽  
Daining Fang ◽  
Guozheng Kang ◽  
...  
Keyword(s):  
3D Printing ◽  
High Speed ◽  
High Performance ◽  
Two Stage ◽  
Thermosetting Polymers
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