Further Aspects of Fracture Resistance Measurement on Thin Sheet Material: Yield Stress and Crack Length

2009 ◽  
pp. 99-99-12 ◽  
Author(s):  
AM Sullivan ◽  
J Stoop
Keyword(s):  
Crack Length ◽  
Yield Stress ◽  
Fracture Resistance ◽  
Sheet Material ◽  
Thin Sheet ◽  
Resistance Measurement ◽  
Thin Sheet Material

To the Influence of the Deformation Speed on Hardening Process during the Cold Sheet Forming

2018 ◽  
Vol 284 ◽  
pp. 513-518 ◽  
Author(s):  
Sergey A. Tipalin ◽  
Michael A. Petrov ◽  
N.F. Shpunkin
Keyword(s):  
Sheet Metal Forming ◽  
Metal Forming ◽  
Sheet Material ◽  
Thin Sheet ◽  
Hardening Process ◽  
Deformation Speed ◽  
Thin Sheet Material ◽  
Simulation Results ◽  
Hardening Curve ◽  
Material Forming

The accuracy of the simulation results of stamping processes of thin sheet material depends on the correct properties’ specification, namely stamping ability. Experiments have been carried out and the influence of the deformation speed on the hardening exponent during cold sheet metal forming was studied. It was found out, that strain changed 100 times can influence the strain grade of the hardening curve of about 10%. This regularity has been taken into consideration prior to the calculation in any CAE-software for material forming.

An Investigation on Deformation-Based Micro Surface Texturing

2011 ◽  
Author(s):  
Rui Zhou ◽  
Jian Cao ◽  
Kornel Ehmann ◽  
Chun Xu
Keyword(s):  
Sheet Material ◽  
Thin Sheet ◽  
Surface Texturing ◽  
Channel Depth ◽  
Surface Textures ◽  
Numerical Studies ◽  
Micro Channels ◽  
Thin Sheet Material ◽  
Wear Reduction ◽  
Final Profile

Micro surface textures have various applications, such as friction/wear reduction and bacteria sterilization. Deformation-based micro surface texturing has the potential of economically creating micro surface textures over a large surface area. A novel desktop micro surface texturing system is proposed for efficiently and economically fabricating micro channels on the surface of thin sheet material for micro fluid and friction/wear reduction applications. Both experimental and numerical studies were employed to analyze the problems of the flatness of the textured sheet, the uniform of the channel depth and pile-ups built up during the micro surface texturing process. The results demonstrated a clear relationship between relative velocity of the upper and lower rolls and the flatness of the textured sheet and the final profile of the micro channels.

Reinforced Plastics for Jet Lift Engines

1967 ◽  
Vol 71 (677) ◽  
pp. 355-365 ◽  
Author(s):  
H. E. Gresham ◽  
C. G. Hannah
Keyword(s):  
Sheet Material ◽  
Thin Sheet ◽  
Economic Factor ◽  
Specific Strength ◽  
Reinforced Plastics ◽  
Thin Sheet Material ◽  
Good Heat Resistance ◽  
Ply Orientation ◽  
Rain Erosion ◽  
Good Heat

Summary:—Extensive use of reinforced plastics has contributed significantly to the success of small VTOL engines, notably the Rolls-Royce RB 162 series in whose compressors it has been possible to demonstrate their versatility and ruggedness. The choice of reinforced plastics for such obvious reasons as lightness, specific strength and corrosion resistance has been fully justified, while apparent deficiencies in stiffness and rain erosion resistance have not proved embarrassing.Considerable use has been made of epoxy resin pre-impregnated sheet incorporating non-woven parallel aligned glass fibre, in particular the “Scotchply” series of “pre-pregs”. Exceptionally high fibre contents have been achieved, resulting in higher strengths and moduli than are usual with glass-reinforced plastics and furthermore, since Scotchply has proved so uniform in composition and ply thickness it has been possible to precision-mould most components with such accuracy that machining is eliminated—a major economic factor. Further economies have been achieved by minimising press curing times by the use of latent catalytic type hardeners for the resin systems which, in addition, confer long storage life and good heat resistance. The use of very thin sheet material has allowed much ply orientation within laminates, resulting in substantial and controllable variations in anisotropy, allowing properties to be tailored more nearly to meet the conditions imposed.

A New Coolant Supply Method Using a Coolant Flow Guided Flexible Sheet Attracted to a Wheel Surface

2005 ◽  
Vol 291-292 ◽  
pp. 227-232 ◽  
Author(s):  
Kiyoshi Suzuki ◽  
Shinichi Ninomiya ◽  
Manabu Iwai ◽  
Yoshiaki Shishido ◽  
Tetsutaro Uematsu
Keyword(s):  
Flow Rate ◽  
Sheet Material ◽  
Thin Sheet ◽  
Coolant Flow ◽  
New Method ◽  
Coolant Flow Rate ◽  
Nozzle Outlet ◽  
Wheel Surface ◽  
Profile Grinding ◽  
Thin Sheet Material

To improve the characteristic of the floating nozzle method, a new coolant supply method using a coolant flow guided flexible sheet was developed. In this method, all the coolant supplied from the nozzle outlet can surely be directed immediately to the grinding point, because the coolant flow guided flexible sheet made of a thin sheet material is attracted to the wheel surface automatically, and confines the coolant between the wheel surface and the sheet. Therefore, the coolant can be completely prevented from deviating away from the grinding point. In fact, when the coolant flow rate of 4 l/min was supplied from the upper part of the wheel by using this method, the amount of coolant that reached the grinding point was 18 times higher than the case of only the floating nozzle method. It was clarified that this method had the effect to improve the grinding performance. Furthermore, this new method has a possibility of the wide application such as in profile grinding and cam grinding.

The strength of butt welded joints in thin sheet material

1992 ◽  
Vol 6 (2) ◽  
pp. 151-156
Author(s):  
P Hollmich ◽  
P Dubberstein ◽  
W Möbius
Keyword(s):  
Welded Joints ◽  
Sheet Material ◽  
Thin Sheet ◽  
Thin Sheet Material

scholarly journals Possibilities of precision material micro-processing by laser pulse copper-vapor radiation

2017 ◽  
Vol 2 (2) ◽  
pp. 36-48
Author(s):  
Мишик Казарян ◽  
Mishik Kazaryan ◽  
Николай Лябин ◽  
Nikolay Lyabin ◽  
Александр Григорьянц ◽  
...  
Keyword(s):  
Radiation Power ◽  
Sheet Material ◽  
Thin Sheet ◽  
Visible Spectrum ◽  
Copper Vapor ◽  
Micro Cracks ◽  
Thin Sheet Material ◽  
Spectrum Region ◽  
Experimental Researches

The paper reports the results of experimental researches on microprocessing by laser copper-vapor radiation with wave-lengths of radiation in the visible spectrum region of 510.6 and 578.2 nm and the frequency of pulse repetition of 14-15kHz, a nano-second duration of pulses and a peak power density of 109-1011 W/cm2 in the focused spot light with the diameter of 10…20µkm. The investigations carried out became a basis for the creation of modern automated laser technological plants “Caravelle-2” and “Caravelle-2M” and with the average radiation power of 6-8W, an operation field of horizontal XY- table 100x100 and 200x200mm and positioning accuracy on axes ±2µkm for the precision micro-machining of foil materials – 0.01-0.2mm; “Caravelle-1” and “Caravelle-1M” with the radiation power of 10-15 20-25 W, an operation field of XY-table 150x150mm for the thin-sheet material micro-processing – 0.3-0.5mm and 0.6-1mm. The productivity of the plants mentioned as compared with common methods including also EEM is by an order and more higher. Material micro-processing with laser nano-second copper-vapor radiation ensures a higher quality of a cut: minor roughness of a cut surface (≥1…3µkm) and the area of thermal impact (≤3…5µkm) and stratifications and micro-cracks do not appear in such heat-resistant material as molybdenum and tungsten.

scholarly journals Development of Microstructures with Improved Cryogenic Toughness Through Local Variations in Stress State: Aluminum-Lithium Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
K. T. Venkateswara Rao ◽  
R. O. Ritchie
Keyword(s):  
Stress State ◽  
Sheet Material ◽  
Thin Sheet ◽  
Local Stress ◽  
Cryogenic Temperatures ◽  
Aluminum Lithium ◽  
Thin Sheet Material ◽  
Local Stress State ◽  
Crack Tip Constraint ◽  
Induced Changes

AbstractMicrostructurally-induced changes in the local stress state (triaxial constraint) and their effect on fracture-toughness behavior are examined at ambient and cryogenic temperatures in an Al-Li-Cu-Zr alloy, processed in the form of 12.7 mm-thick "naturally laminated" plate containing aligned-weak interfaces and 1.6 mm-thin unlaminated sheet. It is shown that marked improvements in long-transverse (L-T) toughness can be achieved in the plate material at cryogenic temperatures by promoting through-thickness delamination along these interfaces, which relaxes local constraint and promotes a fracture-mode transition from global plane strain to local plane stress. Conversely, in thin sheet material, the absence of such interface delamination leads to a reduction in toughness with decrease in temperature, consistent with the greater degree of crack-tip constraint.

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