Some observations on the failure locus of npn transistors and its improvement using graded collector structures

1988 ◽  
Vol 135 (4) ◽  
pp. 85
Author(s):  
M.J. Humphreys ◽  
K.I. Nuttall
Keyword(s):  
Failure Locus

Ring Specimen Geometry for Determining the Ductility of Tubulars

2016 ◽  
Author(s):  
M. A. Al Khaled ◽  
I. Barsoum
Keyword(s):  
Stress State ◽  
Plane Strain ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Pressure Vessels ◽  
Ring Specimen ◽  
Lode Parameter ◽  
Wide Range ◽  
Failure Locus

Pressure vessels designed in accordance with the ASME BPVC code are protected against local ductile failure. Recent work has shown that local ductile failure highly depends on the stress state characterized by both stress triaxiality (T) and the Lode parameter (L). In this paper, the effect of stress state on the ductility of a tubular steel is studied. Two ring specimen configurations were optimized to allow the determination of the ductile failure locus of both tensile and plane strain loadings. The geometry of both ring specimen configurations was optimized to achieve a plane strain (L = 0) condition and a generalized tension (L = −1) condition. Notches with different radii were machined on both types to achieve a wide range of stress triaxiality. Specimens were manufactured from SA-106 carbon tubular steel and were tested to determine the ductile failure loci as a function of T and L. Failure locus of SA-106 steel was constructed based on the failure instants and was found to be independent of the variation in the Lode parameter. The ASME-BPVC local failure criterion showed close agreement with experimental results.

Finite Element Analysis of the Knee: Development of a Failure Locus for the Anterior Cruciate Ligament

2010 ◽  
Author(s):  
A. Homyk ◽  
A. Orsi ◽  
S. Wibby ◽  
N. H. Yang ◽  
H. N. Hashemi ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Articular Cartilage ◽  
Sports Injuries ◽  
Cruciate Ligament ◽  
Epidemiology Study ◽  
Collateral Ligament ◽  
Element Analysis ◽  
Acl Injuries ◽  
Failure Locus ◽  
Anterior Cruciate

A full or partial tear of the anterior cruciate ligament (ACL) is a common and painful injury that has been estimated to occur approximately 250,000 times annually in the U.S. [1]. Articular cartilage and meniscal injuries are also associated with ACL injuries [2]. ACL injuries can often lead to degenerative osteoarthritis of the articular cartilage [2]. An epidemiology study of athletic injuries by Majewski et al. [3] determined that out of 19,530 sports injuries, 20% were ACL injuries and 8% were medial collateral ligament (MCL) injuries.

New Ring Specimen Geometries for Determining the Failure Locus of Tubulars

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
M. A. Al-Khaled ◽  
I. Barsoum
Keyword(s):  
Stress State ◽  
Plane Strain ◽  
Stress Triaxiality ◽  
Ductile Failure ◽  
Pressure Vessels ◽  
Ring Specimen ◽  
Lode Parameter ◽  
Wide Range ◽  
Failure Locus

Pressure vessels designed in accordance with the ASME BPVC code are protected against local ductile failure. Recent work has shown that local ductile failure highly depends on the stress state characterized by both stress triaxiality (T) and the Lode parameter (L). In this paper, the effect of stress state on the ductility of a tubular steel is studied. Two ring specimen configurations were optimized to allow the determination of the ductile failure locus at both tensile and plane strain loadings. The geometry of both ring specimen configurations was optimized to achieve a plane strain (L=0) condition and a generalized tension (L=-1) condition. Notches with different radii were machined on both types to achieve a wide range of stress triaxiality. Specimens were manufactured from SA-106 carbon tubular steel and were tested to determine the ductile failure loci as a function of T and L. Failure locus of SA-106 steel was constructed based on the failure instants and was found to be independent of the Lode parameter. The ASME-BPVC local failure criterion showed close agreement with experimental results (EXP).

The Effect of Immersion on the Breaking Force and Failure Locus in an Epoxy/Mild Steel System

1992 ◽  
Vol 38 (3-4) ◽  
pp. 255-268 ◽  
Author(s):  
Greg S. Shaw ◽  
Charles E. Rogers ◽  
Joe H. Payer
Keyword(s):  
Mild Steel ◽  
Breaking Force ◽  
Failure Locus

Determination of Parameters for the Damage Mechanics Approach to Ductile Fracture Based on a Single Fracture Mechanics Test

2017 ◽  
Author(s):  
O. J. Coppejans ◽  
C. L. Walters
Keyword(s):  
Fracture Mechanics ◽  
Damage Mechanics ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Single Fracture ◽  
Post Processing ◽  
Local Approach ◽  
Opening Displacement ◽  
Failure Locus ◽  
Material Points

The local approach to modelling ductile tearing is a useful technique to give insight into fracture mechanics. However, applications of the local approach have been stymied by the high cost of finding the parameters that characterize it because of the number of specimens and expensive post-processing that the testing requires. In this paper, a novel iterative method to extract a failure locus from one Crack Tip Opening Displacement (CTOD) specimen is presented. Material points fail under various different stress states in a CTOD specimen, so many different points on the failure locus can be found through thoughtful post-processing in FEA. A phenomological ductile failure locus is fitted through the stress triaxiality, Lode angle, and plastic strains that cause failure at material points in the CTOD test. Simulating a CTOD test with a different aspect ratio has shown that the failure locus found by this method can be predictive, giving both accurate force versus Crack Mouth Opening Displacement (CMOD) curves and realistic fracture surfaces featuring separate tunnelling and shear lips.

Sign in / Sign up

Export Citation Format

Share Document