An Analytical Method for Predicting Direct Tensile Creep Fracture in Brittle Solids Containing Initial Microcracks

2021 ◽  
Author(s):  
Xiaozhao Li ◽  
Chengzhi Qi
Keyword(s):  
Analytical Method ◽  
Tensile Creep ◽  
Creep Fracture ◽  
Brittle Solids ◽  
Direct Tensile

Cycle-Dependent and Time-Dependent Bone Fracture With Repeated Loading

1983 ◽  
Vol 105 (2) ◽  
pp. 166-170 ◽  
Author(s):  
D. R. Carter ◽  
W. E. Caler
Keyword(s):  
Low Cycle Fatigue ◽  
Strain Range ◽  
Creep Damage ◽  
Cyclic Strain ◽  
Fatigue Tests ◽  
Time Dependent ◽  
Tensile Creep ◽  
Repeated Loading ◽  
Time To Failure ◽  
Creep Fracture

Fatigue tests of human cortical bone (up to 1.74 × 106 cycles) were conducted under tension-compression (T-C) and zero-tension (O-T) modes with a 2Hz, stress controlled, sinusoidal loading history. Tensile creep-fracture tests at constant stress levels were also performed. The relationship between the initial cyclic strain range and cycles to failure with the T-C specimens were consistent with that derived previously in low-cycle fatigue under strain control. Using a time-dependent failure model, the creep-fracture data was found to be consistent with previous studies of the influence of strain rate on the monotonic tensile strength of bone. The model also predicted quite well the time to failure for the O-T fatigue specimens, suggesting that creep damage plays an important role in O-T fatigue specimens.

Tensile creep and creep fracture of a fibre-reinforced SiS/SiC composite

1998 ◽  
Vol 39 (6) ◽  
pp. 729-734 ◽  
Author(s):  
B. Wilshire ◽  
F. Carreño ◽  
M.J.L. Percival
Keyword(s):  
Tensile Creep ◽  
Creep Fracture

Combination of Experiments and Continuum Damage Mechanics Approach for Prediction of Creep Fracture in an Advanced 9%Cr Steel

2016 ◽  
Vol 258 ◽  
pp. 591-594 ◽  
Author(s):  
Vàclav Sklenička ◽  
Květa Kuchařová ◽  
Marie Kvapilová ◽  
Petr Král ◽  
Jiří Dvořák
Keyword(s):  
Applied Stress ◽  
Fracture Mode ◽  
Damage Mechanics ◽  
Creep Damage ◽  
Tensile Creep ◽  
Experimental Investigations ◽  
Creep Tests ◽  
P92 Steel ◽  
Creep Fracture ◽  
Damage And Fracture

As candidate materials for high-temperature components, most attention has been paid to improving tempered martensitic creep-resistant 9-12%Cr steels. In this work, creep damage and fracture behaviour of an advanced W-modified P92 steel (ASTM Grade P92) was investigated at 600 and 650°C. Tensile creep tests were followed by fractographic analysis of crept and broken specimens. Besides experimental investigations, the creep damage tolerance parameter λ has been used to assess the creep fracture mode. In accordance with experiments the values of λ indicate variety in the fracture mode and provide some evidence on accelerated degradation of the creep strength. The SEM investigations of creep fracture surface revealed substantial changes in microfractographic features of creep fracture. At high applied stress level, the fracture was frequently transgranular due to local loss of a stability of plastic deformation. The fracture ductility drops with decreasing applied stress, demonstrating ductile dimple (transgranular) to brittle (intergranular cavitation) transition of the fracture mode. It was suggested that both the creep deformation and fracture processes are controlled by the same processes and the rate controlling mechanism is most probably climb of intergranular mobile dislocations.

Densitometric Identification of Primitive Erythroblasts After Reaction With Diaminobenzidine

1973 ◽  
Vol 31 ◽  
pp. 328-329
Author(s):  
John A. Trotter
Keyword(s):  
Red Blood Cells ◽  
Analytical Method ◽  
Blood Cells ◽  
Guinea Pigs ◽  
Specific Protein ◽  
Visual Examination ◽  
Hemoglobin Synthesis ◽  
Peroxidatic Activity ◽  
Small Density

Hemoglobin is the specific protein of red blood cells. Those cells in which hemoglobin synthesis is initiated are the earliest cells that can presently be considered to be committed to erythropoiesis. In order to identify such early cells electron microscopically, we have made use of the peroxidatic activity of hemoglobin by reacting the marrow of erythropoietically stimulated guinea pigs with diaminobenzidine (DAB). The reaction product appeared as a diffuse and amorphous electron opacity throughout the cytoplasm of reactive cells. The detection of small density increases of such a diffuse nature required an analytical method more sensitive and reliable than the visual examination of micrographs. A procedure was therefore devised for the evaluation of micrographs (negatives) with a densitometer (Weston Photographic Analyzer).

Dislocation Substructures Produced During Tensile, Creep, and Fatigue Deformation of Ti3Al at 700°C

1977 ◽  
Vol 35 ◽  
pp. 272-273
Author(s):  
S. M. L. Sastry
Keyword(s):  
Intermetallic Compound ◽  
Strain Rate ◽  
Tensile Creep ◽  
Slip Systems ◽  
Slip Vector ◽  
Superlattice Structure ◽  
Slip Activity ◽  
Dislocation Arrangement ◽  
Ordered Intermetallic ◽  
Tangled Dislocation

Ti3Al is an ordered intermetallic compound having the DO19-type superlattice structure. The compound exhibits very limited ductility in tension below 700°C because of a pronounced planarity of slip and the absence of a sufficient number of independent slip systems. Significant differences in slip behavior in the compound as a result of differences in strain rate and mode of deformation are reported here.Figure 1 is a comparison of dislocation substructures in polycrystalline Ti3Al specimens deformed in tension, creep, and fatigue. Slip activity on both the basal and prism planes is observed for each mode of deformation. The dominant slip vector in unidirectional deformation is the a-type (b) = <1120>) (Fig. la). The dislocations are straight, occur for the most part in a screw orientation, and are arranged in planar bands. In contrast, the dislocation distribution in specimens crept at 700°C (Fig. lb) is characterized by a much reduced planarity of slip, a tangled dislocation arrangement instead of planar bands, and an increased incidence of nonbasal slip vectors.

Bulk standards for low-temperature biological x-ray microanalysis

1984 ◽  
Vol 42 ◽  
pp. 282-283
Author(s):  
P. Echlin ◽  
M. McKoon ◽  
E.S. Taylor ◽  
C.E. Thomas ◽  
K.L. Maloney ◽  
...  
Keyword(s):  
Phase Separation ◽  
Low Temperature ◽  
Analytical Method ◽  
Salt Solutions ◽  
Absolute Concentration ◽  
Cooling Process ◽  
X Ray ◽  
The Absolute ◽  
Analytical Procedures ◽  
Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

Tensile Creep of Y-Si3N4: II. Cavitation

1991 ◽  
Vol 49 ◽  
pp. 972-973 ◽  
Author(s):  
B. J. Hockey ◽  
S. M. Wiederhorn
Keyword(s):  
Silicon Nitride ◽  
Creep Rupture ◽  
Tensile Creep ◽  
Sintering Aids ◽  
Microstructural Changes

ATEM has been used to characterize three different silicon nitride materials after tensile creep in air at 1200 to 1400° C. In Part I, the microstructures and microstructural changes that occur during testing were described, and consistent with that description the designations and sintering aids for these materials were: W/YAS, a SiC whisker reinforced Si3N4 processed with yttria (6w/o) and alumina (1.5w/o); YAS, Si3N4 processed with yttria (6 w/o) and alumina (1.5w/o); and YS, Si3N4 processed with yttria (4.0 w/o). This paper, Part II, addresses the interfacial cavitation processes that occur in these materials and which are ultimately responsible for creep rupture.

On impact upon brittle solids

2000 ◽  
Vol 10 (PR9) ◽  
pp. Pr9-281-Pr9-286 ◽  
Author(s):  
N. K. Bourne ◽  
J. C.F. Millett
Keyword(s):  
Brittle Solids
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