Experimental and 3D FE evaluation of crack initiation energy J1C in Al6061-TiC composites

2018 ◽  
Vol 11 (1) ◽  
pp. 63-72
Author(s):  
M.S. Raviraj ◽  
C.M. Sharanaprabhu ◽  
G.C. Mohankumar
Keyword(s):  
Crack Initiation ◽  
Initiation Energy

Damage and Fracture Mechanisms during Mode I and III Loading of Wood

Holzforschung ◽  
2001 ◽  
Vol 55 (5) ◽  
pp. 525-533 ◽  
Author(s):  
E.K. Tschegg ◽  
K. Frühmann ◽  
S.E. Stanzl-Tschegg
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Fracture Energy ◽  
Fracture Mechanisms ◽  
Mode I ◽  
Mode Iii ◽  
Initiation Energy ◽  
Specific Fracture Energy ◽  
Damage And Fracture ◽  
Specific Fracture

Summary Tests under mode I and mode III loading were performed on side grooved Compact-Tension specimens of larch and beech under steady state crack propagation to study the damage and fracture behaviour and the influence of two fibre orientations. From the complete load-displacement diagram, all important damage and fracture mechanical values (stiffness/compliance, microstructural damage, crack initiation energy, specific fracture energy, etc.) have been determined. Crack initiation energy and specific fracture energy are approximately ten times higher for mode III loading than for mode I loading in both wood species. Crack initiation occurs in mode III under external mode III loading, crack propagation, however, takes place under mode I, owing to crack surface interference. The influence of fibre orientation on the (fracture) mechanical properties of beech and larch is different. This difference may be explained mainly by the high number of rays in beech.

Loading Rate Sensitivity of Fracture Absorption Energy of Bainitic-Austenitic TRIP Steel

2015 ◽  
Vol 833 ◽  
pp. 3-6
Author(s):  
Qian Zhou ◽  
Li He Qian ◽  
Jiang Ying Meng ◽  
Lei Jie Zhao ◽  
Fu Cheng Zhang
Keyword(s):  
Crack Initiation ◽  
Trip Steel ◽  
Loading Rate ◽  
Rate Sensitivity ◽  
Crack Initiation And Propagation ◽  
Initiation Energy ◽  
Loading Rates ◽  
Absorption Energy ◽  
Initiation And Propagation

Fracture absorption energies of U-notched and pre-cracked samples of a bainitic-austenitic TRIP steel were studied at different loading rates. The results show that the total absorbed energies increase with increasing the loading rate for the two types of samples. For the U-notched samples, both crack initiation and propagation energies exhibit considerably larger values at higher loading rates. However, for the pre-cracked samples, the crack propagation energy increases noticeably with increasing the loading rate, whereas the crack initiation energy does not show an obvious rise with loading rates. These results are discussed in terms of the amount and role of austenite-to-martensite transformation occurring at various loading rates.

Cracking Resistance Characterization of Asphalt Concrete Containing Reclaimed Asphalt Pavement at Intermediate Temperatures

2017 ◽  
Vol 2633 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Zhou Zhou ◽  
Xingyu Gu ◽  
Fujian Ni ◽  
Qiang Li ◽  
Xiang Ma
Keyword(s):  
Crack Initiation ◽  
Fracture Energy ◽  
Asphalt Concrete ◽  
Asphalt Pavement ◽  
Image Correlation ◽  
Reclaimed Asphalt Pavement ◽  
Cracking Resistance ◽  
Initiation Energy ◽  
Reclaimed Asphalt ◽  
Cumulative Rate

The cracking resistance of asphalt concrete (AC) that contains reclaimed asphalt pavement (RAP) was evaluated in this study with a fracture energy approach. Monotonic and cyclic semicircular bending (SCB) tests were performed with the digital image correlation to correlate crack length with fracture energy. Five types of AC that contained various RAP content (0%, 15%, 30%, 40%, 50%) were evaluated at two intermediate temperatures (15°C and 25°C). On the basis of the relationship between fracture energy and crack extension length, several performance indicators for cracking were proposed: fracture energy and crack initiation energy in monotonic and cyclic SCB tests, an energy cumulative rate in monotonic SCB tests, a fatigue accumulation index (FAI), a fracture energy index, and the slope of the crack steady propagation stage (SOCSP) in cyclic SCB tests. The effects of the RAP content on these indicators were investigated. It was observed from the test results that RAP reduced the fracture energy and crack initiation energy in the monotonic and the cyclic SCB tests. RAP led to a lower energy cumulative rate than an AC mix without RAP in the monotonic SCB tests. Similarly, the FAI and SOCSP values were found to decrease with an increase in RAP content in the cyclic SCB tests. These results indicated that, in general, the addition of RAP reduced the cracking resistance at intermediate temperatures.

The effect of fiber orientation on matrix plasticity and fracture behavior of SiC fiber-reinforced titanium matrix composites

1994 ◽  
Vol 9 (7) ◽  
pp. 1767-1779 ◽  
Author(s):  
Hsing-Pang Chiu ◽  
S.M. Jeng ◽  
J-M. Yang
Keyword(s):  
Plastic Deformation ◽  
Crack Initiation ◽  
Fiber Orientation ◽  
Fracture Behavior ◽  
Critical Energy ◽  
Plastic Deformation Zone ◽  
Initiation Energy ◽  
Critical Energy Release Rate ◽  
The Matrix ◽  
Notch Length

The effect of fiber orientation on the matrix plasticity and fracture behavior of SCS-6 fiber-reinforced Ti-15V-3Al-3Cr-3Sn composites was studied. The laminates used in this study were [0]6, [0/±45]s, and [90/±45]s. Three-point bending tests were conducted on chevron-notched specimens to determine the crack initiation energy, fracture toughness, and fracture strength as a function of notch length. The critical energy release rate was determined from the slope of the crack initiation energy versus notch length curve. The damage evolution and development of the matrix plastic deformation zone at the notch tip during the crack initiation and propagation as a function of fiber orientation were also determined. The relationships among the crack-tip matrix plastic deformation zone size, the critical energy release rate, and notch strength of the composites were discussed.

Impact Properties of TIG Welded AZ31 Magnesium Alloy Joints

2010 ◽  
Vol 638-642 ◽  
pp. 1512-1517
Author(s):  
Toshikatsu Asahina ◽  
Kazuyoshi Katoh ◽  
Hiroshi Tokisue
Keyword(s):  
Magnesium Alloy ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Welded Joints ◽  
Industrial Robot ◽  
Weight Ratio ◽  
Az31 Magnesium Alloy ◽  
Damping Capacity ◽  
Initiation Energy ◽  
Impact Properties

Magnesium and its alloys are the lightest among the metallic materials which are in common use, having a high strength-to-weight ratio along with an excellent machinability and a high damping capacity.　Because of these characteristics, nowadays they are applied to various structural parts such as aircraft, automobiles, optical and electronic instruments, industrial robot components. 　TIG welded joints of AZ31 magnesium alloy has high joint efficiency which can be obtained by the selection of optimum welding conditions. If the welded joints of magnesium alloy are applied to the structure materials, it is very important not only the strength of under static load but also the strength of under dynamic load. However, there is only few report about impact properties of welded AZ31 magnesium alloy joints. In this research, AZ31 magnesium alloy plates 6 mm in thickness were welded on butt welding of square groove without root gap and filler wire using TIG welding process. AZ31 magnesium alloy was carried out at various welding conditions. The effects of welding conditions and notch location on impact properties were studied. Impact values of welded joints were nearly equal to those of the base metal, regardless of welding current. In case of the notched specimens of welded joints, crack initiation energy showed slightly lower than crack propagation energy, regardless of notch location. But, unnotched specimens of welded joints, crack initiation energy showed remarkably high value than crack propagation energy. This means, crack initiation energy spent the large amount of total absorbed energy.

Rubber Fracture Characterization Using J-Integral

1988 ◽  
Vol 16 (1) ◽  
pp. 44-60 ◽  
Author(s):  
C. L. Chow ◽  
J. Wang ◽  
P. N. Tse
Keyword(s):  
Crack Initiation ◽  
Carbon Black ◽  
Natural Rubber ◽  
Fracture Parameter ◽  
J Integral ◽  
Specimen Length ◽  
Fracture Characterization ◽  
Premature Failure ◽  
Testing Procedures ◽  
Material Evaluation

Abstract The use of the J-integral to investigate fracture characterization in a carbon black reinforced natural rubber is described. Three applications to crack initiation are included: two based on the use of a hypothetical zero specimen length and one on conventional testing procedures for metals. While the validity of the zero-length methods is questionable, the conventional method yielded a consistent Jc value of 1.01 N/mm for a typical tire compound. This value was obtained from 24 combinations of varying specimen geometries and pre-crack lengths. The J-integral is revealed as a valid fracture parameter that is applicable not only for material evaluation but also for designing tire structures to resist premature failure. These conclusions disagree with those from an earlier investigation, so the causes for the discrepancies are examined and discussed.

Analysis of the Crack Initiation at Non-Metallic Inclusions in High-Strength Steels

2012 ◽  
Vol 49 (8) ◽  
pp. 468-479 ◽  
Author(s):  
P. Grad ◽  
B. Reuscher ◽  
A. Brodyanski ◽  
M. Kopnarski ◽  
E. Kerscher
Keyword(s):  
Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Metallic Inclusions
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