scholarly journals Experimental study on mechanical property and stone-chip resistance of automotive coatings

2021 ◽  
Author(s):  
Yang Liu ◽  
Chenqi Zou ◽  
Mengyan Zang ◽  
Shunhua Chen
Keyword(s):  
High Speed ◽  
Paint Film ◽  
Tensile Load ◽  
Single Layer ◽  
Impact Angle ◽  
Oblique Impact ◽  
Strong Nonlinearity ◽  
Automotive Coatings ◽  
Impact Tester ◽  
Paint Films

Abstract The damage of automotive coatings caused by stone impact is a problem that has attracted great attention from automotive companies and users. In this work, experiments were conducted to investigate the dynamic tensile properties and stone-chip resistance of automotive coatings. Four kinds of paint films and three typical coatings (single-layer electrocoat coating, single-layer primer coating, and multilayered coating) were used. Under dynamic tensile load using split Hopkinson tension bar (SHTB), the engineering stress-strain curves of the paint films at medium and high strain rates (from 50 to 600 s-1) were obtained. Results indicated that the mechanical properties of the paint films exhibited strong nonlinearity and strain-rate correlation. A modified anti-impact tester was used to complete repeatable single impact tests. The effects of some key parameters, i.e., impact velocity, impact angle, and paint film thickness, on the stone-chip resistance of coatings were systematically investigated. The influence of contact type under high-speed impact conditions was investigated as well. The surface morphologies of the coatings after impact were examined by scanning electron microscopy (SEM), and the failure mechanism of the coatings under normal/oblique impact was discussed. In all experiments, the paint films showed brittle fracture behavior.

Reliability Models of GSM-R Redundant Network on High-Speed Railway

2012 ◽  
Vol 198-199 ◽  
pp. 1783-1788
Author(s):  
Jun Ting Lin ◽  
Jian Wu Dang
Keyword(s):  
Network Architecture ◽  
High Speed ◽  
Failure Time ◽  
Network Reliability ◽  
Single Layer ◽  
Double Layers ◽  
High Speed Railway ◽  
Reliability Models ◽  
Single Layer Network ◽  
Wireless Architectures

As a dedicated digital mobile communication system designed for railway application, GSM-R must provide reliable bidirectional channel for transmitting security data between trackside equipments and on-train computer on high-speed railways. To ensure the safety of running trains, redundant network architecture is commonly used to guarantee the reliability of GSM-R. Because of the rigid demands of railway security, it is important to build reliability mathematical models, predict the network reliability and select a suitable one. Two common GSM-R wireless architectures, co-sited double layers network and intercross single layer network, are modeled and contrasted in this paper. By calculating the reliabilities of each reliable model, it is clear that more redundant the architecture is, more reliable the system will be, the whole system will bear a less failure time per year as the benefit. Meanwhile, as the redundancy of GSM-R system raises, its equipment and maintenance will cost much, but the reliability raise gently. From the standpoint of transmission system interruption and network equipment failure, the reliability of co-sited double layer network architecture is higher than the intercross single layer one, while the viability and cost of the intercross redundant network is better than co-sited one in natural disasters such as flood and lightning. Taking fully into account reliability, viability and cost, we suggest that intercross redundant network should be chosen on high-speed railway.

scholarly journals Nanoprinted high-neuron-density optical linear perceptrons performing near-infrared inference on a CMOS chip

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Elena Goi ◽  
Xi Chen ◽  
Qiming Zhang ◽  
Benjamin P. Cumming ◽  
Steffen Schoenhardt ◽  
...  
Keyword(s):  
Machine Learning ◽  
High Speed ◽  
Near Infrared ◽  
Single Layer ◽  
Infrared Region ◽  
Optical Devices ◽  
Medical Diagnostics ◽  
Oxide Semiconductor ◽  
Process Data ◽  
Neuron Density

AbstractOptical machine learning has emerged as an important research area that, by leveraging the advantages inherent to optical signals, such as parallelism and high speed, paves the way for a future where optical hardware can process data at the speed of light. In this work, we present such optical devices for data processing in the form of single-layer nanoscale holographic perceptrons trained to perform optical inference tasks. We experimentally show the functionality of these passive optical devices in the example of decryptors trained to perform optical inference of single or whole classes of keys through symmetric and asymmetric decryption. The decryptors, designed for operation in the near-infrared region, are nanoprinted on complementary metal-oxide–semiconductor chips by galvo-dithered two-photon nanolithography with axial nanostepping of 10 nm1,2, achieving a neuron density of >500 million neurons per square centimetre. This power-efficient commixture of machine learning and on-chip integration may have a transformative impact on optical decryption3, sensing4, medical diagnostics5 and computing6,7.

A Study on the Deformation due to High Speed Processing of Aircraft Wing Structure

2021 ◽  
Vol 880 ◽  
pp. 63-68
Author(s):  
Jihye An ◽  
Hyunji Kim ◽  
Dohyeon Kim ◽  
Sangkyoo Nam ◽  
Yunyoong Yoo ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Speed ◽  
Tensile Force ◽  
Tensile Load ◽  
Working Hours ◽  
Frictional Heat ◽  
Aviation Industry ◽  
High Speed Machining ◽  
Skilled Workers ◽  
Processing Site

Residual stresses generated during high-speed machining of spoiler beams used in aircraft cause product deformation and dimensional mismatch, which increases the defect rate and leads to material waste. To overcome this problem, the processing site uses manual modification techniques that stretch part of the workpiece according to the experience of skilled workers. However, due to the nature of the aviation parts industry, there are no established methods for modification of product shapes and parts. Studying the modification process would allow for increased productivity, such as shorter working hours, throughout the aviation industry. In this study, a method of predicting residual stress due to frictional heat generated during high-speed machining and applying a tensile force to a model deformed by residual stress was used to modify the product. Our analysis showed that a degree of deformation similar to the measured value was produced, and that the product was modified by applying a tensile load.

Damage Observation and Analysis of a Rock Brazilian Disc Using High-Speed DIC Method

2011 ◽  
Vol 70 ◽  
pp. 87-92 ◽  
Author(s):  
Shao Peng Ma ◽  
Dong Yan ◽  
Xian Wang ◽  
Yan Yan Cao
Keyword(s):  
Strain Field ◽  
Damage Evolution ◽  
High Speed ◽  
Failure Process ◽  
Tensile Load ◽  
Brazilian Test ◽  
Elastic Model ◽  
Strain Fields ◽  
Brazilian Disc ◽  
Damage And Failure

Observation of damage evolution is of great importance to the understanding of the failure process of rock materials. High-speed DIC system is constructed and used to observe the strain field evolution of the granodiorite disc in Brazilian test. The strain fields at different load levels are analyzed based on the stain abnormality indicator (SAI) which is the ratio of the strain measured in experiment to the strain from theoretical solution in an isotropy and elastic model. SAI could be used to indicate the damage in the specimen. The process of damage and failure of the specimen in Brazilian disc test is quantitatively analyzed and deeply discussed according to the strain fields and the statistics of SAI. Experimental results in this paper show that the failure process of the disc specimen in Brazilian test is not simple crack propagation under tensile load, but a complicated damage evolution procedure.

Miscellaneous Studies in Hard-Hammer Percussion Flaking: The Effects of Oblique Impact

1975 ◽  
Vol 40 (2Part1) ◽  
pp. 203-207 ◽  
Author(s):  
John D. Speth
Keyword(s):  
Impact Angle ◽  
Oblique Impact ◽  
Steel Balls ◽  
Vertical Impact

Steel balls were dropped on to massive glass prisms at an impact angle of 45° in order to determine the effects of oblique impact on several attributes of flake size and flake shape. The results indicate that a flake produced by oblique impact is shorter, but not significantly thinner (except in the immediate area of the cone), than a flake of comparable platform thickness produced by vertical impact.

scholarly journals Abrasive jet micro-machining of metals

2021 ◽  
Author(s):  
Sayeed Ally
Keyword(s):  
Normal Incidence ◽  
Impact Angle ◽  
Oblique Impact ◽  
Micro Machining ◽  
Surface Evolution ◽  
Abrasive Particles ◽  
Micro Features ◽  
Semi Empirical ◽  
First Time ◽  
Good Agreement

Abrasive jet micro-machining is a process that utilizes small abrasive particles entrained in a gas stream to erode material, creating micro-features such as channels and holes. Erosion experiments were carried out on aluminum 6061-T6, Ti-6A1-4V alloy, and 316L stainless steel using 50 μm A1₂O₃ abrasive powder launched at an average speed of 106 m/s. The dependence of erosion rate on impact angle was measured and fitted to a semi-empirical model. The erosion data was used in an analytical model to predict the surface evolution of unmasked channels machined with the abrasive jet at normal and oblique incidence, and masked channels at normal incidence. The predictions of the model were in good agreement with the measured profiles for unmasked channels at normal and oblique impact, and masked channels in at normal incidence up to an aspect ratio (channel depth/width) of 1.25. For the first time, it has been demonstrated that the surface evolution of features machined in metals can be predicted.

scholarly journals Influence of TiO2 Nanocrystals on Alkyd Resin Paint Films to Protect Metals

2020 ◽  
pp. 87-94
Author(s):  
Le Huy Hai ◽  
Le Mai Xuan Truc ◽  
Nguyen Quoc Trung
Keyword(s):  
Alkyd Resin ◽  
Paint Film ◽  
Powder Coating ◽  
Nano Tio2 ◽  
Actual Equipment ◽  
Study Results ◽  
Tio2 Nanomaterials ◽  
Paint Films ◽  
The Impact ◽  
Over Time

Aim and Objectives: Nowadays, nanomaterials technology is developing very quickly and bringing high economic efficiency for many industries including paint. The purpose of this study is to assess the effect of paint properties when replacing TiO2 powder coating with nano TiO2 at different ratios. Materials and Methods: The research method is selecting the traditional alkyd paint formula, then replacing this coating powder TiO2 with nano TiO2 to monitor the properties of the paint film over time. Methods of analyzing the properties of the paint film are based on Vietnam standards. Results: The study results showed that TiO2 coating powder replaced by TiO2 nanomaterials has increased the properties of the paint film, improving the thickness, gloss, and durability of the paint film. Nano TiO2 increases from 0.5% to 24% by weight, the impact increased by about 11% (73 to 82 kg.cm), Glossy 60° increased by about 12%, Glossy 85° increased by about 12%, especially the durability of paint film over time increased nearly double. Nano TiO2 is a more expensive material than TiO2, so it should replace less than 4% by weight to increase the quality of the paint film, this ratio is changed according to the actual equipment requirements. Conclusions: The higher the rate of replacing TiO2 materials with TiO2 nano, the better the properties of the paint film. Therefore, nano-material TiO2 is a good coating in alkyd resin for metal paint, it improves the properties of paint film better than TiO2 material.

scholarly journals Dynamic properties of stainless steel under direct tension loading using a simple gas gun

2018 ◽  
Vol 183 ◽  
pp. 02035 ◽  
Author(s):  
Anatoly Bragov ◽  
Alexander Konstantinov ◽  
Leopold Kruszka ◽  
Andrey Lomunov ◽  
Andrey Filippov
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Dynamic Properties ◽  
Tensile Load ◽  
Hopkinson Pressure Bar ◽  
Direct Tension ◽  
Stress Strain ◽  
Gas Gun

The combined experimental and theoretical approach was applied to the study of high-speed deformation and fracture of the 1810 stainless steel. The material tests were performed using a split Hopkinson pressure bar to determine dynamic stress-strain curves, strain rate histories, plastic properties and fracture in the strain rate range of 102 ÷ 104 s-1. A scheme has been realized for obtaining a direct tensile load in the SHPB, using a tubular striker and a gas gun of a simple design. The parameters of the Johnson-Cook material model were identified using the experimental results obtained. Using a series of verification experiments under various types of stress-strain state, the degree of reliability of the identified mathematical model of the behavior of the material studied was determined.

Integrated guidance and control of interceptors with impact angle constraint against a high-speed maneuvering target

2019 ◽  
Vol 233 (14) ◽  
pp. 5192-5204
Author(s):  
Guanjie Hu ◽  
Jianguo Guo ◽  
Jun Zhou
Keyword(s):  
Control System ◽  
High Speed ◽  
Control Method ◽  
Impact Angle ◽  
Adaptive Sliding Mode Control ◽  
Guidance And Control ◽  
Maneuvering Target ◽  
Integrated Guidance And Control ◽  
And Control ◽  
Impact Angle Constraint

An integrated guidance and control method is investigated for interceptors with impact angle constraint against a high-speed maneuvering target. Firstly, a new control-oriented model with impact angle constraint of the integrated guidance and control system is built in the pitch plane by combining the engagement kinematics and missile dynamics model between the interceptor and target. Secondly, the flight path angle of the target is estimated by extended Kalman filter in order to transform the terminal impact angle constraint into the terminal line-of-sight angle constraint. Thirdly, a nonlinear adaptive sliding mode control law of the integrated guidance and control system is designed in order to directly obtain the rudder deflection command, which eliminates time delay caused by the traditional backstepping control method. Then the Lyapunov stability theory is used to prove the stability of the whole closed-loop integrated guidance and control system. Finally, the simulation results confirm that the integrated guidance and control method proposed in this paper can effectively improve the interception performance of the interceptor to a high-speed maneuvering target.

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