Control of Band/Drum Interface Temperature in Automatic Transmissions and the Impact Upon Friction System Durability

1990 ◽  
Author(s):  
Christian J. Castanien
Keyword(s):  
Interface Temperature ◽  
Automatic Transmissions ◽  
The Impact

scholarly journals Experimental Research on the Impact of Interface Temperature on the Adhesion Properties of Clay under the Condition of Different Contacting Time

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tao Qiu ◽  
Yonggang Zhang
Keyword(s):  
Adhesion Force ◽  
Interface Temperature ◽  
Heating Process ◽  
Adhesion Properties ◽  
Interfacial Temperature ◽  
Short Time ◽  
Hot Surface ◽  
Shield Machine ◽  
The Impact

Mud cakes are very likely to occur at the shield cutter when the shield machine passes through a clay stratum, which adhere to the cutter and reduce the excavation efficiency. Due to the thrust of the cutter, the mud cakes are compacted and cause friction at the soil-structure interface, which results in high temperature and aggravates the adhesion, and the effect tends to become stronger as the heating process lasts. In this paper, the effects of the interface temperature and the contacting time between the soil and the hot surface on the adhesion properties of the soil were studied by a self-made adhesion test device. According to the findings, at low interfacial temperature (≤40°C), both the adhesion force and the amount of adhered soil were insignificant in a short term, and the effects were found to be strengthened as the contacting time went on; at the high interfacial temperature (≥50°C), very significant soil adhesion occurred at the structure surface within a short time, and as the contacting time increased, the amount of the adhered soil decreased rapidly while the adhesion force kept increasing, and both tended to remain a constant and become independent with the temperature after a long-term contact. This study is of guiding significance for understanding the formation and development of the shield mud cakes during shield construction.

A Leidenfrost Point Model for Impinging Droplets and Sprays

2004 ◽  
Vol 126 (2) ◽  
pp. 272-278 ◽  
Author(s):  
John D. Bernardin ◽  
Issam Mudawar
Keyword(s):  
Sessile Drop ◽  
Bubble Nucleation ◽  
Interface Temperature ◽  
Solid Interface ◽  
Interfacial Pressure ◽  
Fluid Properties ◽  
Leidenfrost Temperature ◽  
Size Characterization ◽  
The Impact ◽  
Surface Cavity

This study presents, for impinging droplets and sprays, a model of the Leidenfrost point (LFP); the minimum liquid/solid interface temperature required to support film boiling on a smooth surface. The present model is an extension of a previously developed sessile drop model, based on bubble nucleation, growth, and merging criteria, as well as surface cavity size characterization [3]. The basic concept of the model is that for liquid/solid interface temperatures at and above the LFP, a sufficient number of cavities are activated and the bubble growth rates are sufficiently fast that a continuous vapor layer is established nearly instantaneously between the liquid and the solid. For impinging droplets, the influence of the rise in interfacial pressure created by the impact of the droplet with the surface, must be accounted for in determining fluid properties at the liquid-solid interface. The effect of droplet impact velocity on the LFP predicted by the model is verified for single impinging droplets, streams of droplets, as well as sprays. While the model was developed for smooth surfaces on which the roughness asperities are of the same magnitude as the cavity radii (0.1–1.0 μm), it is capable of predicting the boundary or limiting Leidenfrost temperature for rougher surfaces with good accuracy.

Analysis of Dynamic Characteristics of Automatic Transmission Shifting Control

2014 ◽  
Vol 643 ◽  
pp. 42-47 ◽  
Author(s):  
Yan Xiao Fu ◽  
Liang Yi Cui ◽  
Xiang Yang Xu ◽  
Peng Dong
Keyword(s):  
Simulation Model ◽  
Control Strategy ◽  
Model Simulation ◽  
Automatic Transmission ◽  
Test Results ◽  
Shift Quality ◽  
Impact Function ◽  
Automatic Transmissions ◽  
Simulation Results ◽  
The Impact

Basing on the fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. The transmitted torque of the oncoming shift elements before synchronization point can be reduced by an impact function in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with an accurate dynamic model, simulation results and test results are neighborhood data, the simulation model can be used to help realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.

scholarly journals Experimental Research on the Impact of Temperature on the Adhesion Characteristics of Soil-Structure Interface

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Tao Qiu ◽  
Cheng Liu ◽  
Xiaochun Zhong ◽  
Yueyue Zhu
Keyword(s):  
Moisture Content ◽  
Adhesion Force ◽  
Great Influence ◽  
Effect Of Temperature ◽  
Interface Temperature ◽  
Shield Tunneling ◽  
Mud Cake ◽  
Influence Of Temperature On ◽  
Cutter Head ◽  
The Impact

Under the working condition of mud cake, the continuous action between the shield cutter head and the soil on the excavation surface can generate high temperature in the process of shield tunneling and excavation, which changes the characteristic of the adhesion between the soil and the cutter head to intensify the phenomenon of making a mud cake on cutter, finally leading to a vicious circle. To study the effect of temperature on the characteristics of the adhesion of the soil on the surface of the structure, the soil adhesive situation and adhesion force at different interface temperatures were tested through a self-made experiment device. According to the result, it was indicated that the moisture content has a significant effect on the adhesion force of the soil, and the adhesion force firstly increased and then decreased with the increased of the moisture content and reached the maximum value near the plastic limit moisture content. The adhesion force changes very gently when the interface temperature is low. When the temperature reached 50°C, the adhesion force continues to increase as the interface temperature continuously increases except for the soils with high moisture content; moreover, the interface temperature has a great influence on the content of soil adhered on the structure surface. As for the soil with moderate moisture content ( ω = 21.21 ~ 31 %), this content of the adhered soil increased exponentially with the increase of interface temperature; this content firstly decreased and then increased when the moisture content was high. When the soil was dry, there was almost no adhered soil on the surface and the interface temperature had no effect on the adhesive situation. By comparing and analyzing the adhesion state of the soil on the surface of the structure, the influence of temperature on the adhesion characteristics is mainly reflected on the variation of the soil moisture content within the influence range of the interface, the variation of the energy required for the destruction of the adhesion interface, and the change of the location of the weakest antistripping plane induced by both before. This research can better understand the law of formation and development of mud cakes and provided a new idea of solving the problem of mud cakes on the cutter head.

scholarly journals Increasing Snow–Soil Interface Temperature in Farmland of Northeast China from 1979 to 2018

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 878
Author(s):  
Xiuxue Chen ◽  
Xiaofeng Li ◽  
Lingjia Gu ◽  
Xingming Zheng ◽  
Guangrui Wang ◽  
...  
Keyword(s):  
Snow Cover ◽  
Snow Depth ◽  
Northeast China ◽  
Climatic Conditions ◽  
Cold Climate ◽  
Impact Factors ◽  
Control Factor ◽  
Interface Temperature ◽  
The Impact ◽  
Soil Interface

The presence of seasonal snow cover in the cold season can significantly affect the thermal conditions of the ground. Understanding the change of the snow–soil interface temperature (TSS) and its environmental impact factors is essential for predicting subnivean species changes and carbon balance in future climatic conditions. An improved Snow Thermal Model (SNTHERM) is employed to quantify TSS in farmland of Northeast China (NEC) in a 39-year period (1979–2018) firstly. This study also explored the variation tendency of TSS and its main influencing factors on grid scale. The result shows that annual average TSS and the difference between TSS and air temperature (TDSSA) increased rapidly between 1979 and 2018 in the farmland of NEC, and we used the Mann–Kendall test to further verify the increasing trends of TSS and TDSSA on aggregated farmland of NEC. The correlation analysis showed that mean snow depth (MSD) is the most pivotal control factor in 95% of pixels and TDSSA increases as MSD increases. Snow depth can better predict the change of TSS in deep–snow regions than average winter temperature (TSA). The results of this study are of great significance for understanding the impact of snow cover on the energy exchange between the ground and the atmosphere in the cold climate.

scholarly journals Molecular dynamics simulation of interface atomic diffusion in ultrasonic metal welding

2021 ◽  
Author(s):  
Shimaalsadat Mostafavi ◽  
Franz Bamer ◽  
Bernd Markert
Keyword(s):  
Molecular Dynamics ◽  
Autonomous Vehicles ◽  
Ultrasonic Welding ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Atomic Diffusion ◽  
Interface Temperature ◽  
Compression Rate ◽  
Sliding Velocity ◽  
The Impact

AbstractThe formation of a reliable joint between a large number of aluminum strands for battery applications is crucial in automotive industry, especially in the technology of autonomous vehicles. Therefore, in this study, mechanical deformations and diffusion patterns of the mating interface in ultrasonic welding of aluminum were investigated using molecular dynamics simulations. Furthermore, microscopic observations of the joints between aluminum strands from ultrasonic welding illustrating the influence of two process parameters were done. To study the nanomechanics of the joint formation, two aluminum crystallites of different orientations were built. The impact of the sliding velocity and the compression rate of the upper crystal block on the diffusion pattern at the interface of the two crystallites were quantified via the diffusion coefficient. Tensile deformations of several joint configurations were performed to investigate the load-bearing capacity of the solid state bond, taking into account the compression rate, the sliding velocity and the crystallite orientation. The atomic scale simulations revealed that the orientations of the crystallites govern the interface diffusion and the tensile strength of the joint significantly. Furthermore, interface atom diffusion increased with increasing the sliding velocity. Additionally, it was observed that a higher sliding velocity enhances the friction heat generation between the crystallites and significantly increases the interface temperature.

scholarly journals Temperature evaluation and performance comparison of various cooling techniques in drilling of grade 5 titanium alloy

2021 ◽  
pp. 213-213
Author(s):  
Nivin Joy ◽  
S. Prakash ◽  
A. Krishnamoorthy ◽  
A. Anderson
Keyword(s):  
Optimum Condition ◽  
Feed Rate ◽  
Cutting Forces ◽  
Thrust Force ◽  
Response Surfaces ◽  
Cryogenic Cooling ◽  
Interface Temperature ◽  
Drilling Process ◽  
Grade 5 ◽  
The Impact

Heat dissipation is a foremost issue in machining of materials and to overcome this different cooling techniques are adopted to improve the surface integrity and diminish microstructural damage and to effectively flush chips produced. In this research, machinability of titanium grade 5 (Ti-6Al-4V) was carried out through drilling process considering three different cooling procedures like cryogenic cooling (CO2), palm oil based minimum quantity lubrication (MQL) and wet/flood cooling with general cutting fluid (emulsifiers). Experiments were prearranged in par with Taguchi?s technique and a suitable L18 orthogonal array was formulated and the outputs obtained viz., interface temperature and cutting forces (torque/thrust force) were analyzed by adopting response surface methodology (RSM). For interface temperature, type of coolant is the most influencing factor, whereas for cutting forces, the impact of feed rate, drill speed and type of coolant are significant. Response surfaces were fitted for the outputs and subsequently a higher polynominal regression equation was developed for prediction. The optimum condition obtained for constraint multiobjective optimization using desirability approach was: drill speed of 42.49 m/min, feed rate of 0.05 mm/rev and cooling type as cryogenic cooling. The main objecive is to minimize the interface temperature and torque subjected to the constraint thrust force (?1500 N). Confirmation experiment performed with optimum condition displays a significant enhancement in output results.

Improved Inverse Solutions for On-Line Machine Tool Monitoring

2004 ◽  
Vol 126 (2) ◽  
pp. 311-316 ◽  
Author(s):  
Lorraine Olson ◽  
Robert Throne ◽  
Eric Rost
Keyword(s):  
Machine Tool ◽  
Sensor Data ◽  
Interface Temperature ◽  
Physical Parameters ◽  
Temperature Profiles ◽  
Tool Insert ◽  
Tool Monitoring ◽  
Inverse Solutions ◽  
The Impact ◽  
Original Configuration

The identification of tool/chip interface temperatures from remote sensor measurements is a steady inverse heat transfer problem that arises in online machine tool monitoring. In a previous paper we developed a set of inverse approaches, vector projection inverse methods, specifically for this problem. These methods rely on two types of sensor measurements: temperatures and heat fluxes. However, because of the extreme ill-conditioning of the tool configuration we studied previously, only a very limited amount of information could be obtained using any of the inverse approaches examined. In an effort to understand the impact of physical parameters on the conditioning of the problem we examined two modifications to the simulated cutting tool: we increased the thermal conductivity of the tool insert, and we reduced the thickness of the tool insert. Inverse solutions were computed on both configurations with all methods for two temperature profiles and various noise levels. The estimated tool/chip interface temperature for the high conductivity tool showed no improvement compared to the original configuration, since the temperature profiles on the sensor surface were unchanged. However, for the thinner tool, the estimated temperatures were substantially more accurate than with the original configuration. With this thinner tool configuration, an optimal set of four sensors could be used to estimate these temperatures at the tool/chip interface to within a few degrees, even with noisy sensor data.

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