scholarly journals Architecture and Evolution of Blade Assembly in β-propeller Lectins

Structure ◽  
2019 ◽  
Vol 27 (5) ◽  
pp. 764-775.e3 ◽  
Author(s):  
François Bonnardel ◽  
Atul Kumar ◽  
Michaela Wimmerova ◽  
Martina Lahmann ◽  
Serge Perez ◽  
...  
Keyword(s):  
Blade Assembly

scholarly journals The Influence of a Mistuned Blade’s Staggle Angle on the Vibration and Stability of a Shaft-Disk-Blade Assembly

2008 ◽  
Vol 15 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Yi-Jui Chiu ◽  
Shyh-Chin Huang
Keyword(s):  
Natural Frequencies ◽  
Linear Trend ◽  
Rotor System ◽  
Instability Point ◽  
Blade System ◽  
Blade Assembly ◽  
The Stability

The influence on coupling vibrations and stability among shaft-torsion, disk-transverse and blade-bending of a rotor system with a mistuned blade's staggle angle was investigated analytically. A shaft-disk-blade system has been found existing two types of coupling vibrations, disk-blade (DB), and blade-blade (BB) modes when the shaft was assumed rigid. If the shaft's torsional flexibility was taken into account, an additional type of coupling modes, shaft-disk-blade (SDB), appeared. When an angle-mistuned blade existed, the blades periodicity was destroyed and it was found to change not only the natural frequencies but also the types of modes. Due to blade's mistune, the shaft torsion had to participate to balance such that DB modes vanished and replaced by SDB modes. A mistuned staggle angle was numerically found to alter the natural frequencies in an almost linear trend. At last, the rotational effects were found to merge frequency loci and eventually reached an instability point. Very interestingly, a mistuned blade diminished the possible instability caused by blade-dominating modes, which existed in a perfect and periodic rotor. In words, the rotor might benefit from a mistuned blade from the stability viewpoint. The shaft-dominating mode, yet, was unaffected by the mistune and retained a possible instability.

Performance Simulations of a Gas Turbine Disk-Blade Assembly Employing Miniature Radially Rotating Heat Pipes

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Yiding Cao ◽  
Jian Ling
Keyword(s):  
Heat Pipe ◽  
Numerical Investigation ◽  
Gas Turbines ◽  
Heat Pipes ◽  
Turbine Disk ◽  
Maximum Temperature ◽  
Material Strength ◽  
Inlet Temperature ◽  
Pipe Length ◽  
Blade Assembly

With a substantially increased gas inlet temperature in modern gas turbines, the cooling of turbine disks is becoming a challenging task. In order to reduce the temperature at the disk rim, a new turbine disk incorporating radially rotating heat pipes has been proposed. The objective of this paper is to conduct a numerical investigation for the cooling effectiveness of the rotating heat pipe. One of the major tasks of this paper is to compare the performance between a proposed disk-blade assembly incorporating radially rotating heat pipes and a conventional disk-blade assembly without the heat pipes under the same heating and cooling conditions. The numerical investigation illustrates that the turbine disk cooling technique incorporating radially rotating heat pipes is feasible. The maximum temperature at the rim of the proposed disk can be reduced by more than 100 °C in comparison with that of a conventional disk without heat pipes. However, the average temperature at the blade airfoil surface can be reduced by only about 10 °C. In addition, both the heat pipe length and diameter have an important effect on the turbine disk cooling. Under the permission of material strength, a longer heat pipe or a larger heat pipe diameter will produce a lower temperature at the disk rim.

scholarly journals Parameter Interval Uncertainty Analysis of Internal Resonance of Rotating Porous Shaft–Disk–Blade Assemblies Reinforced by Graphene Nanoplatelets

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5033
Author(s):  
Yi Cai ◽  
Zi-Feng Liu ◽  
Tian-Yu Zhao ◽  
Jie Yang
Keyword(s):  
Uncertainty Analysis ◽  
Internal Resonance ◽  
Micromechanical Model ◽  
Porous Metal ◽  
Graphene Nanoplatelets ◽  
Interval Uncertainty ◽  
Width Ratio ◽  
Rotating Shaft ◽  
Parameter Interval ◽  
Blade Assembly

This paper conducts a parameter interval uncertainty analysis of the internal resonance of a rotating porous shaft–disk–blade assembly reinforced by graphene nanoplatelets (GPLs). The nanocomposite rotating assembly is considered to be composed of a porous metal matrix and graphene nanoplatelet (GPL) reinforcement material. Effective material properties are obtained by using the rule of mixture and the Halpin–Tsai micromechanical model. The modeling and internal resonance analysis of a rotating shaft–disk–blade assembly are carried out based on the finite element method. Moreover, based on the Chebyshev polynomial approximation method, the parameter interval uncertainty analysis of the rotating assembly is conducted. The effects of the uncertainties of the GPL length-to-width ratio, porosity coefficient and GPL length-to-thickness ratio are investigated in detail. The present analysis procedure can give an interval estimation of the vibration behavior of porous shaft–disk–blade rotors reinforced with graphene nanoplatelets (GPLs).

scholarly journals Fracture Failure Mechanisms of Long Single PA6 Fibers

2017 ◽  
Author(s):  
Huiling Ding ◽  
Yongzhen Zhang ◽  
Zhitao He
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Failure Process ◽  
Failure Mechanisms ◽  
Tensile Failure ◽  
Fractographic Analysis ◽  
Fiber Failure ◽  
Fracture Failure ◽  
Blade Assembly ◽  
Fiber Materials

The present study investigates the failure mechanisms of industrial fiber materials, using a custom designed fiber cutting performance test bench. The fracture morphologies of single PA6 fibers are examined by scanning electron microscopy. The analysis reveals that fiber cutting can be distinguished according to four distinct stages of fiber failure represented by shearing, cutting, brittle fracture, and tensile failure, which are the result of different mechanisms active during the processes of crack initiation, extension and fracture. The results of fractographic analysis are further verified by an analysis of the blade assembly speed with respect to time over the entire fracture failure process based on high-speed camera data. The results of fractographic analysis and blade assembly speed are fully consistent.

A Field Emission Probe Forming System with a Magnetic Pre-Accelerator Lens

1976 ◽  
Vol 34 ◽  
pp. 522-523 ◽  
Author(s):  
Huei Pei Kuo ◽  
Benjamin M. Siegel
Keyword(s):  
Field Emission ◽  
Power Dissipation ◽  
Spot Size ◽  
Beam Current ◽  
Magnetic Lens ◽  
Razor Blade ◽  
Computer Optimization ◽  
Exciting Coil ◽  
Blade Assembly ◽  
Magnetic Transfer

A field emission electron probe forming system with a magnetic preaccelerator lens has been developed.The magnetic lens has been designed using computer optimization for best compromise between high lens quality, ease of tip manipulation and tolerable power dissipation of the exciting coil. Figure 1 shows the configuration of the magnetic lens and the field emission tip assembly. The optical properties of the magnetic lens are plotted in Figure 2.The performance of the magnetic pre-accelerator lens was evaluated with a prototype electron optical bench developed by Veneklasen. It consists of a two cylinder accelerator, a magnetic transfer lens and a projector lens followed by a razor blade assembly for measurement of the spot size and the beam current.

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