scholarly journals Techniques for Thin-Walled Element Milling with Respect to Minimising Post-Machining Deformations

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4723
Author(s):  
Magdalena Zawada-Michałowska ◽  
Józef Kuczmaszewski ◽  
Stanisław Legutko ◽  
Paweł Pieśko
Keyword(s):  
High Speed ◽  
High Performance ◽  
Rolling Direction ◽  
High Speed Cutting ◽  
Analysis Of Results ◽  
Parallel Direction ◽  
Considerable Impact ◽  
Thin Walled ◽  
Technological History ◽  
The Impact

The paper examines the impact of selected machining techniques and the semi-finished product technological history on deformations of thin-walled elements made of EN AW-2024 T351 aluminium alloy after milling. The following techniques have been implemented: High Performance Cutting, High Speed Cutting, conventional finishing (CF) and combinations of these techniques. As for the semi-finished product technological history, the rolling direction has been analysed. It has been assumed that it can be relevant in relation to the cutting tool feed direction and, in consequence, exert considerable impact on the stress, as well as deformation following machining. The interest in this issue proceeds from significant challenges faced by the industry, particularly in the aerospace sector. The analysis of results obtained has shown that milling in the direction perpendicular to the rolling direction results in larger deformations than milling in the parallel direction. Additionally, it has been revealed that applying a correctly selected machining technique makes it possible to minimise post-machining deformations of thin-walled elements.

Investigation of the Impact Analysis of Microscale Thin-Walled Structures Manufactured by High-Speed Machining

2006 ◽  
Vol 326-328 ◽  
pp. 1599-1602
Author(s):  
Bo Sung Shin
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
High Speed ◽  
Impact Analysis ◽  
Thin Wall ◽  
High Speed Machining ◽  
High Speed Cutting ◽  
Thin Walled Structures ◽  
Thin Walled ◽  
The Impact

High-speed machining (HSM) is very useful method as one of the most effective manufacturing processes because it has excellent quality and dimensional accuracy for precision machining. Recently micromachining technologies of various functional materials with very thin walls are needed in the field of electronics, mobile telecommunication and semiconductors. However, HSM is not suitable for microscale thin-walled structures because of the lack of their structure stiffness to resist high-speed cutting force. A microscale thin wall machined by HSM shows the characteristics of the impact behavior because the high-speed cutting force works very shortly on the machined surface. We propose impact analysis model in order to predict the limit thickness of a very thin-wall and investigate its limit thickness of thin-wall manufactured by HSM using finite element method. Also, in order to verify the usefulness of this method, we will compare finite element analyses with experimental results and demonstrate some applications.

scholarly journals Pre-Machining of Rolled Plates as an Element of Minimising the Post-Machining Deformations

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4777
Author(s):  
Magdalena Zawada-Michałowska ◽  
Józef Kuczmaszewski ◽  
Paweł Pieśko
Keyword(s):  
Surface Layer ◽  
High Speed ◽  
High Performance ◽  
Rolling Direction ◽  
Rolling Process ◽  
Textured Surface ◽  
Technological Parameters ◽  
Feed Direction ◽  
Thin Walled ◽  
Rolled Plates

The paper presents the influence of the milling strategy, the relation between the cutting tool feed direction and the rolling direction, as well as the pre-machining consisting of the removal of the textured surface layer of rolled plates in the rolling process on the thin-walled elements deformations made of the EN AW-2024 T351 wrought aluminium alloy, after milling. The research used strategies such as: high-performance cutting (HPC), high-speed cutting (HSC) and conventional milling (CM), as well as their combinations. Another tested variable was the relation between the tool feed direction and the rolling direction. In addition, the tests were carried out in the following versions: leaving the textured surface layer created after plastic working and with its removal with technological parameters corresponding to HSC and CM. Based on the obtained results, it was found that the post-machining deformation of thin-walled elements can be minimised owing to the use of a selected milling strategy and its combination with pre-machining (or lack thereof). It was also observed that larger deformations were obtained for samples after milling in the direction perpendicular to the rolling direction.

scholarly journals Monitoring and characterization of vibration and shock conditions aboard high-performance marine craft

2018 ◽  
Vol 233 (4) ◽  
pp. 1068-1081
Author(s):  
Manudul Pahansen de Alwis ◽  
Karl Garme
Keyword(s):  
Real Time ◽  
High Speed ◽  
High Performance ◽  
Severity Index ◽  
Irregular Waves ◽  
Vibration Exposure ◽  
Data Set ◽  
Real Time Analysis ◽  
Impact Acceleration ◽  
The Impact

The stochastic environmental conditions together with craft design and operational characteristics make it difficult to predict the vibration environments aboard high-performance marine craft, particularly the risk of impact acceleration events and the shock component of the exposure often being associated with structural failure and human injuries. The different timescales and the magnitudes involved complicate the real-time analysis of vibration and shock conditions aboard these craft. The article introduces a new measure, severity index, indicating the risk of severe impact acceleration, and proposes a method for real-time feedback on the severity of impact exposure together with accumulated vibration exposure. The method analyzes the immediate 60 s of vibration exposure history and computes the severity of impact exposure as for the present state based on severity index. The severity index probes the characteristic of the present acceleration stochastic process, that is, the risk of an upcoming heavy impact, and serves as an alert to the crew. The accumulated vibration exposure, important for mapping and logging the crew exposure, is determined by the ISO 2631:1997 vibration dose value. The severity due to the impact and accumulated vibration exposure is communicated to the crew every second as a color-coded indicator: green, yellow and red, representing low, medium and high, based on defined impact and dose limits. The severity index and feedback method are developed and validated by a data set of 27 three-hour simulations of a planning craft in irregular waves and verified for its feasibility in real-world applications by full-scale acceleration data recorded aboard high-speed planing craft in operation.

Application and Advance in Super-Hard Tool Material

2011 ◽  
Vol 84-85 ◽  
pp. 228-231
Author(s):  
Jing Su ◽  
Yu Hua Zhang ◽  
Di Wang
Keyword(s):  
High Speed ◽  
High Performance ◽  
Cubic Boron Nitride ◽  
Tool Material ◽  
Polycrystalline Diamond ◽  
High Speed Cutting ◽  
Machining Quality ◽  
Finished Surface ◽  
Materials Used ◽  
Surface Precision

For the excellent properties, super-hard tool material has received much attention from researchers. The development of super-hard tool material for high-speed cutting could brought high machining quality and surface precision. For an engineer, adopt high performance of tool material, for example wearing resistance, high stability of PCD (polycrystalline diamond) and PCBN (poly cubic boron nitride) can get more information for obtaining higher finished surface quality that cannot acquire just by common cutting process. This paper introduces super-hard cutters materials (PCD and PCBN) development, and discusses several material properties. The features of materials used in different cutting fields are given.

scholarly journals Research on Blade-Casing Rub-Impact Mechanism by Experiment and Simulation in Aeroengines

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jie Hong ◽  
Tianrang Li ◽  
Zhichao Liang ◽  
Dayi Zhang ◽  
Yanhong Ma
Keyword(s):  
High Speed ◽  
High Performance ◽  
Element Model ◽  
Physical Parameters ◽  
Test Rig ◽  
Calculation Results ◽  
Rotor Support ◽  
Blade Tip ◽  
Set Up ◽  
The Impact

Aeroengines pursue high performance, and compressing blade-casing clearance has become one of the main ways to improve turbomachinery efficiency. Rub-impact faults occur frequently with clearance decreasing. A high-speed rotor-support-casing test rig was set up, and the mechanism tests of light and heavy rub-impact were carried out. A finite element model of the test rig was established, and the calculation results were in good agreement with the experimental results under both kinds of rub-impact conditions. Based on the actual blade-casing structure model, the effects of the major physical parameters including imbalance and material characteristics were investigated. During the rub-impact, the highest stress occurs at the blade tip first and then it is transmitted to the blade root. Deformation on the impact blade tip generates easily with decreased yield strength, and stress concentration at the blade tip occurs obviously with weaker stiffness. The agreement of the computation results with the experimental data indicates the method could be used to estimate rub-impact characteristics and is effective in design and analyses process.

Simulation of High-Speed Cutting Process Based on ABAQUS

2011 ◽  
Vol 230-232 ◽  
pp. 1221-1225 ◽  
Author(s):  
Xia Yu ◽  
Xu Yao Sun ◽  
Dan Ke Wei
Keyword(s):  
High Speed ◽  
Chip Morphology ◽  
Material Model ◽  
Rake Angle ◽  
Cutting Process ◽  
Fe Model ◽  
High Speed Cutting ◽  
Line Technology ◽  
Chip Separation ◽  
The Impact

Using the separation line technology, established a FE model of two-dimensional cutting process for AISI4340 steel and discussed some basic theory and pivotal questions associated with the simulation of cutting process including the Johnson-Cook material model, the contact model between tool and chip, criteria of chip separation and so on. In order to study the impact of tool rake angle on the chip morphology and the cutting forces, the high-speed cutting process for AISI 4340 steel was simulated based on ABAQUS software. Also, analyzed the influence of mesh azimuth on the chip morphology and its temperature distribution.

scholarly journals Evaluation of the Potential Electromagnetic Interference in Vertically Stacked 3D Integrated Circuits

2020 ◽  
Vol 10 (3) ◽  
pp. 748
Author(s):  
Dipesh Kapoor ◽  
Cher Ming Tan ◽  
Vivek Sangwan
Keyword(s):  
Integrated Circuits ◽  
Integrated Circuit ◽  
Electromagnetic Interference ◽  
High Speed ◽  
High Performance ◽  
Near Field ◽  
Three Dimensional ◽  
3D Ic ◽  
Three Dimensional Integrated Circuit ◽  
The Impact

Advancements in the functionalities and operating frequencies of integrated circuits (IC) have led to the necessity of measuring their electromagnetic Interference (EMI). Three-dimensional integrated circuit (3D-IC) represents the current advancements for multi-functionalities, high speed, high performance, and low-power IC technology. While the thermal challenges of 3D-IC have been studied extensively, the influence of EMI among the stacked dies has not been investigated. With the decreasing spacing between the stacked dies, this EMI can become more severe. This work demonstrates the potential of EMI within a 3D-IC numerically, and determines the minimum distance between stack dies to reduce the impact of EMI from one another before they are fabricated. The limitations of using near field measurement for the EMI study in stacked dies 3D-IC are also illustrated.

Characters of Deformation and Surface Quality and Cutter Wearing at High-Speed Cutting

2020 ◽  
Vol 980 ◽  
pp. 136-143
Author(s):  
Hu Ping An ◽  
Zhi Yuan Rui ◽  
R. Iyer
Keyword(s):  
Surface Quality ◽  
High Speed ◽  
Cutting Speed ◽  
Manganese Steel ◽  
High Manganese ◽  
High Manganese Steel ◽  
High Speed Cutting ◽  
Metal Ceramic ◽  
Cutting Deformation ◽  
The Impact

In this paper, the impact of cutting speed and feed amount on cutting deformation and surface quality and cutter wear have been studied by the test of high manganese steel cutting with metal ceramic tool at high speed. The results show that it is feasible by cutting high manganese steel with cermet tool at high-speed cutting (HSC). Chip changes into succession segment from band in macrostate. Sawteeth can be seen on the top surface of chip while high temperature feature in burning color and cold welding form appear on the bottom of the chip. The model of surface roughness built can be used to predict surface quality at HSC, and provided cutting optimized parameters scheme. Further research indicates that high-speed cutting has its special deformation mechanism and plastic chips exhibit hot brittleness which provides a favorable condition for solving the chip breaking problem in the cutting of high manganese steel.

scholarly journals Impact of Modern Virtualization Methods on Timing Precision and Performance of High-Speed Applications

2019 ◽  
Vol 11 (8) ◽  
pp. 179 ◽  
Author(s):  
Veronika Kirova ◽  
Kirill Karpov ◽  
Eduard Siemens ◽  
Irina Zander ◽  
Oksana Vasylenko ◽  
...  
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
High Speed ◽  
High Performance ◽  
Estimation Accuracy ◽  
Network Applications ◽  
High Speed Network ◽  
Timing Precision ◽  
And Performance ◽  
The Impact

The presented work is a result of extended research and analysis on timing methods precision, their efficiency in different virtual environments and the impact of timing precision on the performance of high-speed networks applications. We investigated how timer hardware is shared among heavily CPU- and I/O-bound tasks on a virtualized OS as well as on bare OS. By replacing the invoked timing methods within a well-known application for estimation of available path bandwidth, we provide the analysis of their impact on estimation accuracy. We show that timer overhead and precision are crucial for high-performance network applications, and low-precision timing methods usage, e.g., the delays and overheads issued by virtualization result in the degradation of the virtual environment. Furthermore, in this paper, we provide confirmation that, by using the methods we intentionally developed for both precise timing operations and AvB estimation, it is possible to overcome the inefficiency of standard time-related operations and overhead that comes with the virtualization. The impacts of negative virtualization factors were investigated in five different environments to define the most optimal virtual environment for high-speed network applications.

scholarly journals Variable rotor speed strategy for coaxial compound helicopters with lift–offset rotors

2019 ◽  
Vol 124 (1271) ◽  
pp. 96-120 ◽  
Author(s):  
Y. Yuan ◽  
D. Thomson ◽  
R. Chen
Keyword(s):  
Power Consumption ◽  
High Speed ◽  
High Performance ◽  
Normal Load ◽  
Flight Dynamics ◽  
Load Factor ◽  
Rotor Speed ◽  
Inverse Simulation ◽  
Maneuvering Flight ◽  
The Impact

ABSTRACTThe coaxial compound helicopter with lift-offset rotors has been proposed as a concept for future high-performance rotorcraft. This helicopter usually utilizes a variable-speed rotor system to improve the high-speed performance and the cruise efficiency. A flight dynamics model of this helicopter associated with rotor speed governor/engine model is used in this article to investigate the effect of the rotor speed change and to study the variable rotor speed strategy. Firstly, the power-required results at various rotor rotational speeds are calculated. This comparison indicates that choice of rotor speed can reduce the power consumption, and the rotor speed has to be reduced in high-speed flight due to the compressibility effects at the blade tip region. Furthermore, the rotor speed strategy in trim is obtained by optimizing the power required. It is demonstrated that the variable rotor speed successfully improves the performance across the flight range, but especially in the mid-speed range, where the rotor speed strategy can reduce the overall power consumption by around 15%. To investigate the impact of the rotor speed strategy on the flight dynamics properties, the trim characteristics, the bandwidth and phase delay, and eigenvalues are investigated. It is shown that the reduction of the rotor speed alters the flight dynamics characteristics as it affects the stability, damping, and control power provided by the coaxial rotor. However, the handling qualities requirements are still satisfied with different rotor speed strategies. Finally, a rotor speed strategy associated with the collective pitch is designed for maneuvering flight considering the normal load factor. Inverse simulation is used to investigate this strategy on maneuverability in the Push-up & Pull-over Mission-Task-Element (MTE). It is shown that the helicopter can achieve Level 1 ratings with this rotor speed strategy. In addition, the rotor speed strategy could further reduce the power consumption and pilot workload during the maneuver.

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