scholarly journals Reliability Analysis of Uniaxially Ground Brittle Materials

1996 ◽  
Vol 118 (4) ◽  
pp. 863-871 ◽  
Author(s):  
J. A. Salem ◽  
N. N. Nemeth ◽  
L. M. Powers ◽  
S. R. Choi
Keyword(s):  
Silicon Carbide ◽  
Flexural Strength ◽  
Fracture Strength ◽  
Mixed Mode ◽  
Strength Distribution ◽  
Principal Stress Direction ◽  
Reliability Models ◽  
Machining Damage ◽  
Fast Fracture ◽  
Strength Distributions

The fast fracture strength distribution of uniaxially ground, alpha silicon carbide was investigated as a function of grinding angle relative to the principal stress direction in flexure. Both as-ground and ground/annealed surfaces were investigated. The resulting flexural strength distributions were used to verify reliability models and predict the strength distribution of larger plate specimens tested in biaxial flexure. Complete fractography was done on the specimens. Failures occurred from agglomerates, machining cracks, or hybrid flaws that consisted of a machining crack located at a processing agglomerate. Annealing eliminated failures due to machining damage. Reliability analyses were performed using two and three-parameter Weibull and Batdorf methodologies. The Weibull size effect was demonstrated for machining flaws. Mixed mode reliability models reasonably predicted the strength distributions of uniaxial flexure and biaxial plate specimens.

scholarly journals Reliability Analysis of Uniaxially Ground Brittle Materials

1995 ◽  
Author(s):  
Jonathan A. Salem ◽  
Noel N. Nemeth ◽  
Lynn M. Powers ◽  
Sung R. Choi
Keyword(s):  
Silicon Carbide ◽  
Flexural Strength ◽  
Fracture Strength ◽  
Mixed Mode ◽  
Strength Distribution ◽  
Principal Stress Direction ◽  
Reliability Models ◽  
Machining Damage ◽  
Fast Fracture ◽  
Strength Distributions

The fast fracture strength distribution of uniaxially ground, alpha silicon carbide was investigated as a function of grinding angle relative to the principal stress direction in flexure. Both as-ground and ground/annealed surfaces were investigated. The resulting flexural strength distributions were used to verify reliability models and predict the strength distribution of larger plate specimens tested in biaxial flexure. Complete fractography was done on the specimens. Failures occurred from agglomerates, machining cracks, or hybrid flaws that consisted of a machining crack located at a processing agglomerate. Annealing eliminated failures due to machining damage. Reliability analyses were performed using two and three parameter Weibull and Batdorf methodologies. The Weibull size effect was demonstrated for machining flaws. Mixed mode reliability models reasonably predicted the strength distributions of uniaxial flexure and biaxial plate specimens.

Prediction of the Strength of Ceramic Tubular Components: Part II — Experimental Verification

1991 ◽  
Author(s):  
D. L. Shelleman ◽  
O. M. Jadaan ◽  
J. C. Conway ◽  
J. J. Mecholsky
Keyword(s):  
Silicon Carbide ◽  
Statistical Theory ◽  
Room Temperature ◽  
Strength Distribution ◽  
Ring Test ◽  
Stress Distributions ◽  
Pressure Test ◽  
Tubular Components ◽  
Tubular Specimens ◽  
Strength Distributions

Abstract The strength distribution of reaction bonded silicon carbide tubes that failed by internal pressurization was predicted from strength distributions obtained from simple laboratory test specimens at room temperature. The strength distributions of flexure bars, C-rings tested in tension, C-rings tested in compression, diametrally compressed O-rings, and internally pressurized short tubes were compared to the strength distribution of internally pressurized long tubes. The methodology involved application of Weibull statistical theory using elasticity theory to define the stress distributions in the simple specimens. The flexural specimens did not yield acceptable results, since they were ground prior to testing, thereby altering their flaw population in comparison with the processing induced flaw populations of the tubular specimens. However, the short tube internal pressure test, the c-ring tested in tension and the diametrally compressed o-ring test configurations yielded accurate predictions, since these specimens more accurately represent the strength limiting flaw population in the long tubes.

scholarly journals Strength Distribution Changes in a Silicon Nitride as a Function of Stressing Rate and Temperature

1998 ◽  
Author(s):  
Andrew A. Wereszczak ◽  
Kristin Breder ◽  
Mark J. Andrews ◽  
Timothy P. Kirkland ◽  
Mattison K. Ferber
Keyword(s):  
Silicon Nitride ◽  
Crack Growth ◽  
Failure Probability ◽  
Life Prediction ◽  
Slow Crack Growth ◽  
Strength Distribution ◽  
Porous Region ◽  
Machining Damage ◽  
Stressing Rate ◽  
Strength Distributions

Machining damage (a surface flaw) and porous-region-flaw (a volume flaw) populations limited the flexure strengths of a commercially available silicon nitride at 25°C, while these same flaws, along with inclusions, limited flexure strengths at 850°C. The machining damage and porous region flaws were the primary interest in the present study because they caused failure at both temperatures. Censoring revealed that the two-parameter Weibull strength distributions representing each flaw population changed as a function of stressing rate (i.e., dynamic fatigue) and temperature. A decrease in the Weibull scaling parameter is recognized as an indication of slow crack growth or time-dependent strength reduction in monolithic ceramics. Available life prediction codes used for reliability predictions of structural ceramic components consider the slow crack growth phenomenon. However, changes in the Weibull modulus are infrequently observed or reported, and typically are not accounted for in these life prediction codes. In the present study, changes in both Weibull parameters for the strength distributions provided motivation to the authors to survey what factors (e.g., residual stress, slow crack growth, and changes in failure mechanisms) could provide partial or full explanation of the observed distribution changes in this silicon nitride. Lastly, exercises were performed to examine the effects of strength distribution changes on the failure probability prediction of a diesel exhaust valve. Because the surface area and volume of this valve were substantially larger than those of the tested bend bars, it was found that the valve’s failure probability analysis amplified some slight or inconclusive distribution changes which were not evident from the interpretation of the censored bend bar strength data.

scholarly journals Simultaneous effects of rice husk silica and silicon carbide whiskers on the mechanical properties and morphology of sodium geopolymer

2020 ◽  
Vol 54 (29) ◽  
pp. 4611-4620 ◽  
Author(s):  
Akm Samsur Rahman ◽  
Chirag Shah ◽  
Nikhil Gupta
Keyword(s):  
Silicon Carbide ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Silica Nanoparticles ◽  
Rice Husk ◽  
Silicon Carbide Whiskers ◽  
Short Beam ◽  
Spherical Silica ◽  
Beam Shear ◽  
Strength Improvement

The current research is focused on developing a geopolymer binder using rice husk ash–derived silica nanoparticles. Four types of rice husks were collected directly from various rice fields of Bangladesh in order to evaluate the pozzolanic activity and compatibility of the derived rice husk ashes with precursors of sodium-based geopolymers. Silicon carbide whiskers were introduced into sodium-based geopolymers in order to evaluate the response of silicon carbide whiskers to the interfacial bonding and strength of sodium-based geopolymers along with rice husk ashes. Compression, flexural and short beam shear tests were performed to investigate the synergistic effect of rice husk ashes–derived silica and commercially available silicon carbide whiskers. Results show that rice husk ashes–derived spherical silica nanoparticles reduced nano-porosity of the geopolymers by ∼20% and doubled the compressive strength. The simultaneous additions of rice husk ashes and silicon carbide whiskers resulted in flexural strength improvement by ∼27% and ∼97%, respectively. The increase in compressive strength due to the inclusion of silica nanoparticles is related to the reduction in porosity. The increase in flexural strength due to simultaneous inclusion of silica and silicon carbide whiskers suggest that silica particles are compatible with the metakaolin-based geopolymers, which is effective in consolidation. Finally, microscopy suggest that silicon carbide whiskers are effective in increasing bridged network and crack resistance.

Fatigue Reliability Functions in Semilogarithmic Coordinates

1991 ◽  
Author(s):  
Vladimir A. Avakov
Keyword(s):  
Fatigue Life ◽  
Coordinate System ◽  
Strength Distribution ◽  
Fatigue Reliability ◽  
Life Distribution ◽  
Similar Transformation ◽  
Asymptotic Type ◽  
Life Distributions ◽  
Strength Distributions

Abstract In the previous publication [2], the transformation between fatigue life and strength distribution was established using double-logarithmic coordinate system (lnN-lnS). Here, a similar transformation is established using a semi logarithmic (lnN-S) coordinate system. With the aid of the developed orthogonal relations, lognormal, Weibull and three-parameter logweibull life distributions have been transformed into normal, asymptotic type 1 of smallest value, and three-parameter Weibull strength distributions, respectively. This procedure may be applied to other types of fatigue life distribution.

analysis of mechanical properties of ceiling boards based on corn cobs and coconut coir waste with latex adhesive

2021 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Ety Jumiati ◽  
Ufik Eliati Tumanggor ◽  
Abdul Halim Daulay
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Fracture Strength ◽  
Test Results ◽  
Hot Press ◽  
Optimal Result ◽  
Corn Cob ◽  
Corn Cobs ◽  
Test Parameters ◽  
Coconut Coir

<p align="center"><strong><em>Abstract</em></strong></p><p>Ceiling evelopment by utilizing waste corn cobs, coconut coir with gypsum flour an the adition of latex adhesive. Variations in the composition of the mixture of corn cobs, coconut coir, gypsum flour with latex adhesive include sample A (0:0:100:15), sample B (3:3:94:15), sample C (6:6:88:15), sample D (9:9:82:15), sample E (12:12:76:15), and sample F (15:15:70:15) with emphasis using a <em>hot press </em>and drying for 28 days. The test parameters include flexural strength and fracture strength. The test results show that sample B in the composition (3:3:94:15) is the optimal result. In this composition, the resulting ceiling board has the characteristics of a flexural strength of 3966,39 kgf/cm<sup>2</sup> and a fracture strength of 1088,6 kgf/cm<sup>2</sup>.</p><p><strong><em>Keyword :</em></strong><em> Lateks , Ceiling Board, Coconut Coir, Corn Cob</em></p><p><em> </em></p>

Evaluation of Scale Dependent of Fast Fracture Strength of Micro Component

2007 ◽  
Author(s):  
Toshikazu Okazaki ◽  
Shunsuke Nakamura ◽  
Hideyuki Hirata ◽  
Yutaka Mihara ◽  
Hidenori Yoshimura
Keyword(s):  
Fracture Strength ◽  
Fast Fracture
Sign in / Sign up

Export Citation Format

Share Document