scholarly journals Effect of grinding residual stress on bending strength of ceramics.

1989 ◽  
Vol 38 (429) ◽  
pp. 582-588 ◽  
Author(s):  
Kenji SUZUKI ◽  
Keisuke TANAKA ◽  
Yuji YAMAMOTO ◽  
Heizaburo NAKAGAWA
Keyword(s):  
Residual Stress ◽  
Bending Strength

High Dynamic Mechanical Strength of Zirconium-Based Bulk Amorphous Alloys

1998 ◽  
Vol 554 ◽  
Author(s):  
Tao Zhang ◽  
Akihisa Inoue
Keyword(s):  
Residual Stress ◽  
Mechanical Strength ◽  
Amorphous Alloys ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Tensile Fracture ◽  
Uniaxial Tensile ◽  
Cast Sample ◽  
Bulk Amorphous Alloys ◽  
Squeeze Cast

AbstractA bulk amorphous Zr55Al10Ni5Cu30 alloy prepared by squeeze casting was found to exhibit high mechanical strength values, i.e., uniaxial tensile fracture strength (σt) of 1850 MPa, three-point bending strength (σb) of 3200 MPa, bending fatigue strength (σf) of 1100 MPa, Charpy impact fracture energy (Ef) of 135 kJ/m2 and fracture toughness of 68 MPa√m. The σb, σf and Ef are about two times higher than those for the corresponding bulk amorphous alloys prepared by unidirectional solidification and powder consolidation techniques, though the σt of the squeeze cast sample is higher by about 15 % than those for the other samples. The remarkable increases in the σb, σf and EF are presumably due to the introduction of high compressive residual stress of about 1240 MPa in the outer surface region only for the squeeze cast sample. The finding of the effectiveness of the compressive residual stress on the increase in the mechanical strength under the bending stress mode is important and expected to be widely used as a new strengthening mechanism for bulk amorphous alloys, as is the case for reinforced oxide glasses subjected to strengthening treatment.

Effect of residual stress on the bending strength of ground Al2O3/TiCN ceramics

2003 ◽  
Vol 80 (1) ◽  
pp. 305-308 ◽  
Author(s):  
Haitao Yang ◽  
Ling Gao ◽  
Runzhang Yuan ◽  
Kyung-Ryul Kim ◽  
Jae-Youn Jung
Keyword(s):  
Residual Stress ◽  
Bending Strength

Identification of process-induced residual stress/strain distribution in thick thermoplastic composites based on in situ strain monitoring using optical fiber sensors

2019 ◽  
Vol 53 (24) ◽  
pp. 3445-3458 ◽  
Author(s):  
Takuhei Tsukada ◽  
Shu Minakuchi ◽  
Nobuo Takeda
Keyword(s):  
Residual Stress ◽  
Strain Distribution ◽  
Bending Strength ◽  
Thermoplastic Composite ◽  
High Rate ◽  
Strength Increase ◽  
Transverse Strain ◽  
Thickness Direction ◽  
Stress Strain ◽  
Thin Carbon

In thick thermoplastic composite laminates, nonuniform temperature distribution arises in the through-thickness direction during high-rate manufacturing processes. This causes the so-called thermal skin-core effect. The surface region solidified in advance constrains shrinking of the inside region, so nonuniform residual stress/strain distribution arises in the through-thickness direction. This study quantitatively clarified this mechanism and identified the amount of residual stress/strain by utilizing fiber optic–based internal strain measurement and process simulation. First, in-plane transverse strain of thin carbon fiber/polyphenylenesulfide laminates was measured using fiber Bragg grating sensors to determine two key parameters for stress/strain simulation; thermal/crystalline shrinkage strain and composite stiffness. Abaqus-based simulation using these properties was then performed to calculate stress/strain distribution in thick laminates. The simulated strain agreed well with the measured value and it was confirmed that the residual stress developed in a relatively low temperature range. In addition, transverse three-point bending tests were conducted to validate the amount of residual stress calculated by the simulation. The bending strength increased by the thermal skin-core effect and the amount of strength increase coincided with the simulation, confirming the validity of the simulation. Extension of the proposed approach to the evaluation of the morphological skin-core effect is also discussed.

Effect of Temperature on Strength and Residual Stress Distribution in Silicon Nitride to 304 Stainless Steel Brazed Joints

2004 ◽  
Vol 449-452 ◽  
pp. 881-884 ◽  
Author(s):  
Do Won Seo ◽  
Ho Chel Yoon ◽  
Jin Yi Lee ◽  
Jae Kyoo Lim
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
High Temperature ◽  
Silicon Nitride ◽  
Residual Stresses ◽  
Bending Strength ◽  
304 Stainless Steel ◽  
Effect Of Temperature ◽  
High Temperature Strength ◽  
Mechanical And Thermal Properties

Ceramics are significantly used in many industrial applications due to their excellent mechanical and thermal properties such as high temperature strength, low density, high hardness, low thermal expansion and good corrosion properties. To combine the specific advantages of ceramics with that of metals, they are often used together within one composite component. In this study, the effect of temperature on fracture characteristics of silicon nitride joined to 304 stainless steel brazed with Ti active alloy are investigated in room and high temperature regions. And analytical studies on the residual stress of dissimilar brazed joint are performed by the finite element method. Four-point bending strength and deflection of interlayer increase with increasing strain rate in room temperature. As the test temperature increases, the bending strength decreases, but the deflection of interlayer is almost constant. The residual stresses redistribute after cutting of joint and the maximum tensile stress occurs on the new free surface at the ceramic near the interface. The singularity of residual stresses at the ceramic near the interface is characterized by elastic-plastic properties of ceramic and inserted materials.­

A Study on Grinding Parameter Optimization of Reaction Bonded Silicon Carbide

2013 ◽  
Vol 631-632 ◽  
pp. 660-665 ◽  
Author(s):  
Yao Wang ◽  
Zha Yan Feng
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Silicon Carbide ◽  
Residual Stresses ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Grinding Parameters ◽  
Depth Analysis ◽  
Cut Depth ◽  
Full Factorial

In order to enhance the efficiency and the surface smooth degree of the RBSiC grinding, a three factors two levels full factorial design was utilized to optimize the process. Combined with the effects of grinding parameters on surface roughness, the grit cut depth analysis was employed to choose the appropriate grinding parameters. The strength reliability and the residual stresses of the RBSiC ground using the optimized parameters were investigated. The results show that comparing to the polished RBSiC the ground ones have higher compressive residual stress, lower crack scatter and similar average bending strength.

scholarly journals Influence of grinding zones on the tooth root bending strength of case carburized gears

2021 ◽  
Author(s):  
Karl Jakob Winkler ◽  
Thomas Tobie ◽  
Karsten Stahl
Keyword(s):  
Residual Stress ◽  
Stress State ◽  
Bending Strength ◽  
Decisive Role ◽  
Experimental Investigations ◽  
Tooth Root ◽  
Industrial Practice ◽  
Application Range ◽  
Residual Stress State ◽  
Root Area

AbstractKnowledge of the expected tooth root bending strength plays a decisive role in the design of gear sets. Due to dimensional and shape changes resulting from distortion due to the heat treatment, unintentional, partial grinding in the tooth root area may occur, particularly in the application range of large gears. The influences of an unintentional grinding zone on the tooth root bending strength have not yet been clarified with sufficient accuracy. As a result, grinding zones lead to uncertainties when evaluating the tooth root bending strength and thus to a loss of time and cost in the field of industrial practice.This paper presents experimental investigations on the influence of grinding zones on the tooth root bending strength of case carburized gears. For the experimental investigations, there are three unground reference variants with different blasting treatments: non-blasted, mechanical cleaned by shot blasting and shot peened. The unground reference variants are examined regarding their tooth root bending strength. For the other test gear variants, different grindings zones are applied resulting in light and strong material removal by grinding. The variants with the different grinding zones are examined analogously regarding their tooth root bending strength and are subsequently compared to the reference variants.The results of the experimental investigations show that grinding zones can have diverse influences on the tooth root bending strength of case carburized gears– Non-blasted gears do not show changes regarding the tooth root bending strength with regard to light or strong grinding zones applied within this investigation.– Shot blasted (mechanical cleaned) gears show no change in the tooth root bending strength for light grinding zones (grinding application does not significantly alter the original residual stress state in the tooth root area).– Shot blasted (mechanical cleaned) gears show a reduction of the tooth bending strength of up to 20 % with regard to strong grinding zones (grinding application does significantly alter the original residual stress state in the tooth root area).– Shot peened gears show a behavior similar to that of shot blasted gears with reductions of the tooth root bending strength of up to 30 %.– Shot peening the strong grinding zones as a repair measure can increase the reduced tooth root bending strength again. However, for the investigated test gears, the resulting tooth root bending strength was below the shot blasted reference variant.The results of this paper help to evaluate the influence of grinding zones on the tooth root bending strength of case carburized gears more precisely compared to the generalized reductions of current standards and classifications. The results can be incorporated in standards such as DIN 3390 as well as ISO 6336 and can be applied in the field of industrial practice. Eventually, the findings help to reduce the current loss of time and cost caused by uncertainties regarding grinding zones.

scholarly journals Improvement in Bending Strength of Silicon Nitride through Laser Peening

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 315
Author(s):  
Kazuya Saigusa ◽  
Joji Yamamoto ◽  
Koji Takahashi ◽  
Fumiaki Kumeno ◽  
Norihito Shibuya
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Silicon Nitride ◽  
Compressive Residual Stress ◽  
Bending Strength ◽  
Fracture Initiation ◽  
Laser Peening ◽  
Initiation Point

This study aimed to improve the bending strength and reliability of ceramics using laser peening (LP). In the experiment, LP without coating (LPwC) and with coating (LPC) were applied to silicon nitride (Si3N4) under various conditions. The surface roughness, residual stress, and bending strength were then measured for the non-LP, LPwC, and LPC specimens. The results show that the LPwC specimen had a greater surface roughness but introduced larger and deeper compressive residual stress when compared with the non-LP and LPC specimens. In addition, the bending strength of the LPwC specimen was higher and scatter in bending strength was less compared with the non-LP and LPC specimens. This may be attributed to the transition of the fracture initiation point from the surface to the interior of the LPwC specimen because of the compressive residual stress introduced near the surface. Thus, it was demonstrated that the application of LP is effective in improving the strength and reliability of ceramics.

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