Effects of the Stress Concentration and Plane Stress on the Essential Work of Fracture (EWF) Method

2014 ◽  
Vol 1042 ◽  
pp. 32-37
Author(s):  
Chao Zhao ◽  
Xiong Chen ◽  
Chang Sheng Zhou ◽  
Hong Mei Wang
Keyword(s):  
Stress Concentration ◽  
Plane Stress ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Uniaxial Tensile ◽  
Geometric Features ◽  
Double Edge ◽  
Double Base ◽  
Relationship Of ◽  
The Relationship

In this article, we used standard dumbbell specimen (SDS), compact tension specimen (CTS) and Double edge notched specimen (DENS) which made of materials of modified double-base propellant to do the uniaxial tensile experiments under different tensile rates. In comparison, three kinds of specimen whoes geometric features are similar with the specimen above but the thickness is smaller, were also used to get the relationship of force (F) and displacement (l). After analysis of these relationship, we confirmed that the plane stress and stress concentration influence the use of EWF method. The experimental results prove that the geometric features of the specimen which are proposed by B.cotterell and J.K.reddel are absolutely right. But for the thicker specimen used by GUAN GONG and other researchers, we can just know the trend is correct, and should do further research to know the influence which specimen’s geometric characteristics bring to experiment.

Stress Distribution in Be Compact Tension Specimen

2007 ◽  
Vol 561-565 ◽  
pp. 2033-2036
Author(s):  
Rui Wen Li ◽  
Ping Dong
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
X Ray ◽  
Measured Stress ◽  
Local Stresses ◽  
Fracture Behaviors

Beryllium (Be) is susceptible to introduce stress because it is a brittle metal with a high elastic modular. The compact tension (CT) specimens of beryllium were designed to determinate stress and fracture behaviors. Stress distribution near notch in CT beryllium was measured by the combination of an X-ray stress analysis and a custom-designed load device. The results show that local stresses near notch tip are much higher than those on other area. Thus, stress concentration lead the CT specimens fracture along the notch direction. Residual stresses due to machining are remained. A finite element ( FE ) calculation on the same loaded geometry was made, and the result is agreement with the measured stress distribution near notch.

Tensile testing low density multilayers: Aluminum/titanium

1998 ◽  
Vol 13 (10) ◽  
pp. 2902-2909 ◽  
Author(s):  
D. Josell ◽  
D. van Heerden ◽  
D. Read ◽  
J. Bonevich ◽  
D. Shechtman
Keyword(s):  
Thin Films ◽  
Yield Stress ◽  
Tensile Testing ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Low Density ◽  
Multilayer Thin Films ◽  
Bilayer Thickness ◽  
Relationship Of ◽  
The Relationship

Yield stresses, ultimate tensile strengths, and specific strengths of aluminum/titanium multilayer thin films are determined from the results of uniaxial tensile tests. The plasticity in the stress-strain curves, the nature of the fracture surfaces, and the relationship of the yield stress and the bilayer thickness are discussed. Properties are compared with those of other multilayer materials published in the literature.

Effect of Side Grooves on Plane Stress Fracture Behavior of Compact Tension Specimens Made of Ultra-High Strength Steel

2016 ◽  
Vol 713 ◽  
pp. 159-162
Author(s):  
M. Dabiri ◽  
T. Skriko ◽  
M. Amraei ◽  
T. Björk
Keyword(s):  
Stress Fracture ◽  
Plane Stress ◽  
High Strength Steel ◽  
Surface Deformation ◽  
Stress Triaxiality ◽  
High Strength ◽  
Compact Tension ◽  
Uniaxial Tensile ◽  
Fracture Plane ◽  
Ultra High Strength Steel

Thin compact tension specimens made of direct quenched ultra-high strength steel were tested under constant rate uniaxial tensile load. The length of the crack was monitored using optical microscopes on both sides of the specimens during the fatigue pre-cracking (using a chevron V-notch). Deformations during the crack lengthening were recorded by a full-field measurement technique using a set of digital cameras to check the effect of side grooves on reduction of surface deformation. The Specimen without side grooves showed a high level of plasticity, thickness reduction, and crack growth along a deviating path. In addition, the fracture surface showed excessive failure along the inclined plane. The presence of side grooves, however, led to the decrease of the maximum applied force at final fracture while the force prior to crack tearing was almost the same as the specimen without side grooves. Grooves significantly reduced the inclination of the fracture plane and plastic deformation due to removal of low stress triaxiality on the surface. They led to the fracture along a straight path and approximately even surface which makes them beneficial especially when compliance method is used in plane stress fracture tests.

Simplification of the Parametric Transformation Equations for Analysis of Plane Stress

2012 ◽  
Vol 591-593 ◽  
pp. 2499-2503
Author(s):  
Mao Lin Du ◽  
Guo Liang Chen ◽  
Kui Ying Pu
Keyword(s):  
Plane Stress ◽  
Maximum Stress ◽  
Extreme Value ◽  
Shear Stresses ◽  
Angular Parameter ◽  
Two Systems ◽  
Relationship Of ◽  
The Relationship ◽  
Parametric Transformation ◽  
Mohr’S Circle

For the analysis of plane stress, there are two methods, transformation of equation and Mohr’s circle. With the former method, the two principle angles are found by taking derivative to determine the extreme value of stresses. However, it is unknown which one of the two principle angles corresponding to the maximum stress. Moreover, the relationship between the two methods is inexplicit, as the angle of the rotation of the element is eliminated to derive the equation of Mohr’s circle. Using trigonometric relations, considering two systems of sign conventions for shear stresses, simplified parametric transformation equations are obtained. A unique principle angle is easy to be found corresponding to a principle stress. It is obvious that the graph of the simplified equations is a circle. The relationship of the angle of the rotation of the element and the angular parameter of the circle is explicit.

The Relationship of the Resistance Curve and Gc to Specimen Configuration

1977 ◽  
Vol 28 (1) ◽  
pp. 28-38 ◽  
Author(s):  
N J I Adams ◽  
H G Munro
Keyword(s):  
Fracture Toughness ◽  
Plastic Zone ◽  
Aluminium Alloys ◽  
Crack Extension ◽  
Thin Sheet ◽  
Compact Tension ◽  
Resistance Curve ◽  
Resistance Curves ◽  
Relationship Of ◽  
The Relationship

SummaryFollowing a brief introduction, an examination is presented of the factors which define fracture toughness, resistance-curve relationships and the extent of stable crack extension in thin-sheet failure. Tests have been performed on three aluminium alloys to establish the variations in the shape of resistance curves, using both compliance-indicated and measured absolute values of crack length in compact tension specimens and centre crack sheets. The results show that both the toughness and the resistance curves of the two specimen types are different and that these differences cannot be explained wholly by consideration of crack tip plastic zone sizes.

The Fined COD Transform Formula for CT Specimens to Investigate Material Fracture Toughness

2012 ◽  
Vol 188 ◽  
pp. 11-16
Author(s):  
Yao Yao ◽  
Li Xun Cai ◽  
Chen Bao ◽  
Han Jiang
Keyword(s):  
Crack Opening ◽  
Crack Tip ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Element Analysis ◽  
Material Fracture ◽  
Crack Tip Opening ◽  
The Relationship

For front-force compact tension specimen (FFCT), based on the refined results of the relationship between crack tip opening displacement and load line crack opening displacement from Finite Element Analysis (FEA), the influences of material properties and plastic deformation near the crack tip have been analyzed. A simplified and accurate transform formula for FFCT specimens is presented in this paper, and the error analysis is conducted.

Effect of Transition Curve on Gear Bending Strength

2010 ◽  
Vol 34-35 ◽  
pp. 1640-1644
Author(s):  
Li Ping Wang ◽  
Ying Qiang Xu ◽  
Lei Lei Wang ◽  
Qiong Wei Zhang
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Bending Strength ◽  
Transition Curve ◽  
Relation Model ◽  
Relationship Of ◽  
The Relationship ◽  
Transition Curves

Transition curve is very important to bending strength and life of gear. In order to improve the bending strength of gear, the shape of three kinds of transition curve (ordinary fillet cutter tip, single circle arc cutter tip and double circle arc cutter tip) was analyzed respectively, the relationship of double circle arc cutter tip parameters was established, the relation model of sensitive part of gear and stress concentration factor ( J and γ) was determined, the effect of different transition curves of gear on bending strength ( ) was explored. The results of analysis show that the bending strength of gear cut by double circle arc cutter tip increases by 10% comparing with that of gear cut by ordinary fillet cutter tip. It provides theories foundation for the design of high bending strength gear.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

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