Skip Nav Destination
Close Modal
By
Sara Fernandez, María José Quintana, José Ovidio García, Luis Felipe Verdeja, Roberto González ...
By
Christopher A. Walton, Benjamin E. Nesbit, Henrique M. Candia, Zachary A. Myers, Wilburn R. Whittington ...
By
Cassio Barbosa, Simone Kessler de Barros, Ibrahim de Cerqueira Abud, Joneo Lopes do Nascimento, Sheyla Santana de Carvalho
Update search
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
Filter
- Title
- Authors
- Author Affiliations
- Full Text
- Abstract
- Keywords
- DOI
- ISBN
- EISBN
- Issue
- ISSN
- EISSN
- Volume
- References
NARROW
Format
Topics
Book Series
Date
Availability
1-20 of 34
Mixed-mode fracture
Close
Follow your search
Access your saved searches in your account
Would you like to receive an alert when new items match your search?
1
Sort by
Series: ASM Handbook
Volume: 11B
Publisher: ASM International
Published: 15 May 2022
DOI: 10.31399/asm.hb.v11B.a0006919
EISBN: 978-1-62708-395-9
Abstract
This article reviews the impact response of plastic components and the various methods used to evaluate it.. It describes the effects of loading rate on polymer deformation and the influence of temperature and strain rate on failure mode. It discusses the advantages and limitations of standard impact tests, the use of puncture tests for assessing material behavior under extreme strain, and the application of fracture mechanics for analyzing impact failures. It also develops and demonstrates the theory involved in the design and analysis of thin-walled, injection-molded plastic components.
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001753
EISBN: 978-1-62708-241-9
Abstract
A failure analysis investigation was conducted on a fractured aluminum tailwheel fork which failed moments after the landing of a privately owned, 1955 twin-engine airplane. Nondestructive evaluation via dye-penetrant inspection revealed no discernible surface cracks. The chemical composition of the sand-cast component was identified via optical emission spectroscopy and is comparable to an aluminum sand-cast alloy, AA 712.0. Metallographic evaluation via optical microscopy and scanning electron microscopy revealed a high degree of porosity in the microstructure as well as the presence of deleterious intermetallic compounds within interdendritic regions. Macrohardness testing produced hardness values which are noticeably higher than standard hardness values for 712.0. The primary fracture surfaces indicate evidence of mixed-mode fracture, via intergranular cracking, cleaved intermetallic particles, and dimpled cellular regions in the matrix. The secondary fracture surface demonstrates similar features of intergranular fracture.
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001760
EISBN: 978-1-62708-241-9
Abstract
This article presents a failure analysis of an aluminum cylinder head on an automotive engine. During an endurance test, a crack initiated from the interior wall of a hole in the center of the cylinder head, then propagated through the entire thickness of the component. Metallurgical examination of the crack origin revealed that casting pores played a role in initiating the crack. Stress components, identified by finite element analysis, also played a role, particularly the stresses imposed by the bolt assembly leading to plastic strain. It was concluded that the failure can be prevented by eliminating the bolt hole, using a different type of bolt, or adjusting the fastening torque.
Book Chapter
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001816
EISBN: 978-1-62708-241-9
Abstract
This paper describes the superplastic characteristics of shipbuilding steel deformed at 800 °C and a strain rate less than 0.001/s. After the superplastic deformation, the steel presents mixed fractures: by decohesion of the hard (pearlite and carbides) and ductile (ferrite) phases and by intergranular sliding of ferrite/ferrite and ferrite/pearlite, just as it occurs in stage III creep behavior. The behavior is confirmed through the Ashby-Verrall model, according to which the dislocation creep (power-law creep) and diffusion creep (linear-viscous creep) occur simultaneously.
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001821
EISBN: 978-1-62708-241-9
Abstract
A fire in a storage yard engulfed several propane delivery trucks, causing one of them to explode. A series of elevated-temperature stress-rupture tears developed along the top of the truck-mounted tank as it was heated by the fire. Unstable fracture then occurred suddenly along the length of the tank and around both end caps, following the girth welds that connect them to the center portion of the tank. The remaining contents of the tank were suddenly released, aerosolized, and combusted, creating a powerful boiling liquid expanding vapor explosion (BLEVE). Based on the metallography of the tank pieces, the approximate tank temperature at the onset of explosion was determined. Metallurgical analysis provided additional insights as well as a framework for making tanks less susceptible to this destructive failure mechanism.
Book Chapter
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001781
EISBN: 978-1-62708-241-9
Abstract
A commercial hybrid-iron golf club fractured during normal use. The club fractured through its cast aluminum alloy hosel. Optical analysis revealed casting pores through 20% of the hosel thickness. Mechanical properties were determined from characterization results, then used to construct a finite element model to analyze material performance under failure conditions. In addition, a full scale structural test was conducted to determine failure strength. It was concluded that the club failed not from ground impact but from a force reversal at the bottom of the downswing. Large moments generated during the downswing aggravated by manufacturing defects and stress concentration combined to create an overload condition.
Book Chapter
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001791
EISBN: 978-1-62708-241-9
Abstract
A pipe in the lateral wall of a boiler powering an aircraft carrier flat-top boat failed during a test at sea. The pipe was made from ASTM 192 steel, an adequate material for the application. Microstructural analysis along with equipment operating records provided valuable insight into what caused the pipe to rupture. Although the pipe had been replaced just 50 h before the accident, the analysis revealed incrustations and corrosion pits on the inner walls and oxidation on the outer walls. Microstructural changes were also observed, indicating that the steel was exposed to high temperatures. The combined effect of pitting, incrustations, and phase transformations caused the pipe to rupture.
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001801
EISBN: 978-1-62708-241-9
Abstract
Both rods in a Harrington rod cervical stent failed after a short time in service. Metallurgical analysis revealed a significant number of notches as well as enlarged grain size in one of the two rods, rough shallow-cracked surfaces along the bend profiles, possible signs of corrosion, and fractures (on both rods) near indentations imparted by retaining clamps. The observations suggest that surface roughness and bending defects initiated cracking that led to the fatigue failure of the compromised rod, followed some time later by the overload fracture of the second rod.
Series: ASM Failure Analysis Case Histories
Volume: 3
Publisher: ASM International
Published: 01 December 2019
DOI: 10.31399/asm.fach.v03.c9001802
EISBN: 978-1-62708-241-9
Abstract
Superelastic nitinol wires that fractured under various conditions were examined under a scanning electron microscope in order to characterize the fracture surfaces, produce reference data, and compare the findings with prior published work. The study revealed that nitinol fracture modes and morphologies are generally consistent with those of ductile metals, such as austenitic stainless steel, with one exception: Nitinol exhibits a unique damage mechanism under high bending strain, where damage occurs at the compression side of tight bends or kinks while the tensile side is unaffected. The damage begins as slip line formation due to plastic deformation, which progresses to cracking at high strain levels. The cracks appear to initiate from slip lines and extend in shear (mode II) manner.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.usage.c0090988
EISBN: 978-1-62708-236-5
Abstract
A jack cylinder split open during simulated service testing. The intended internal test pressurization was reportedly analogous to typical service. The material and mechanical properties of the cylinder pipe were unknown, although subsequent testing showed that the pipe satisfied the requirements for a grade 1045 medium-carbon, plain carbon steel. Investigation (visual inspection, chemical analysis, 2% nital etched 119x images, and tension testing) supported the conclusion that the cylinder pipe burst in a mixed brittle-ductile manner due to overpressurization. It is likely that the bearing strength of the pipe was slightly compromised by a low-strength layer of decarburization. Recommendations included evaluating the testing procedure for the possibility of inadvertent overpressurization and analyzing successfully tested cylinders to identify changes in material, and perhaps heat treatment, that may have contributed to this failure.
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001252
EISBN: 978-1-62708-235-8
Abstract
An octagonal steel ingot weighing 13 tons made of manganese-molybdenum steel developed gaping cross-cracks on all eight sides in the forging press during initial pressure application. It was reported that the steel had been melted in a basic 12-ton arc furnace, oxygenated, furnished with 42 kg of 75% ferrosilicon and 12 kg aluminum additions, alloyed with 160 kg of 80% ferromanganese, and finally deoxidized in the ladle with 42 kg calcium silicon. For metallographic examination a plate approximately 100 mm thick was cut parallel to one of the eight planes. Platelet-like particles could be discerned on the conchoidal fracture planes with the SEM. The precipitates proved to be thin and partially transparent platelets of a hexagonal crystal lattice whose parameters resemble those of AIN. The precipitates were at least in part still undissolved in spite of the long holding period at high initial forging temperature. Another block melted under the same conditions and immediately after the defective one, was forged into a gear ring without any trouble. This ring was free of grain boundary precipitates, but it contained only 0.012 % AI and 0.0102 % N.
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c0049797
EISBN: 978-1-62708-235-8
Abstract
An AISI 4340 threaded steel connecting rod that was part of a connecting linkage used between a parachute and an instrumented drop test assembly fractured under high dynamic loading when the assembly was dropped from an airplane. A large flaw that originated from the root of a machined thread groove was visible on the fracture surface. Heavy oxidation at elevated temperatures was indicated as most of the surface of the flaw was black. Fine secondary cracks aligned transverse to the growth direction was revealed by scanning electron microscopy. It was established that intergranular cracking observed in this alloy was caused during heat treating as the thread root served as an effective stress concentration and induced quench cracking. It was found that fracture in the overload region occurred by a ductile void growth and coalescence process. Premature failure of the threaded rod was thus attributed to the presence of the quench crack flaw caused by an improper machining sequence and heat treatment practice.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.rail.c9001444
EISBN: 978-1-62708-231-0
Abstract
To permit bolting of a 90 lb/yd. flat-bottomed rail to a steel structure, rectangular slots 2 in. wide x 1 in. deep were flame-cut in the base of the rail at 2 ft intervals to suit existing bolt holes. During subsequent handling, one of the rails (which were about 25 ft long) was dropped from a height of approximately 6 ft on to a concrete floor and it fractured into 11 pieces, each break occurring at a slot. The sample piece submitted for examination showed a wholly brittle fracture at each end, the fractures having originated at the sharp corners of the slots. During flame-cutting, a narrow band of material on each side of the cut was raised above the hardening temperature. When the torch had passed the rate of abstraction of heat from this zone by conduction into the cold mass of the rail was sufficiently rapid to amount to a quench and thus cause local hardening. The steel in the regions of the slots possessed little capacity for deformation, and fracturing of the martensitic layer, under cooling or impact stresses, would be likely to occur. The slots should have been cut mechanically.
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.rail.c9001585
EISBN: 978-1-62708-231-0
Abstract
On 15 March 2000, a National Railroad Passenger Corporation (Amtrak) train traveling from Chicago to Los Angeles derailed in Carbondale, KS. After the initial on-scene investigation, 12 pieces of rail were sent to the materials laboratory for examination. Ten of them were from the point of derailment (POD). A vertical crack was observed in the head of the rail (vertical split head). The crack was at least 233 in. (591 cm) long, continuing through the entire lengths of most pieces recovered from the POD. The vertical fracture surface had features consistent with overstress fracture with short-term exposure to an oxygen-rich environment. Fracture features emanated from longitudinally-aligned inclusions rich in aluminum.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.bldgs.c0090943
EISBN: 978-1-62708-219-8
Abstract
A very large diameter worm gear that had been in service in a dam for more than 60 years exhibited cracks and was removed. It was reported that the high-strength, low-ductility cast bronze gear was only rarely stressed during service, associated with infrequent opening and closing of gates. Due to the age of the gear and the time frame of its manufacture, no original material specifications or strength requirements could be located. Likewise, no maintenance records of possible repairs to the gear were available. Investigation (visual inspection, chemical analysis, tension and hardness testing, 119x SEM images, and potassium dichromate etched 297x metallographic images) supported the conclusion that the bronze gear cracked via mixed-mode overload, rather than by a progressive mechanism such as fatigue or stress-corrosion cracking. The cracking was not associated with regions that would be highly stressed and did not appear to be consistently correlated to casting imperfections, repair welds, or associated heat-affected zones. Cracking across the gear face suggested that bending forces from misalignment were likely responsible for the cracking. Recommendations included further review of the potential root cause.
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.modes.c0048498
EISBN: 978-1-62708-234-1
Abstract
A graphite-epoxy tapered-box structure, which consisted of two honeycomb skin panels fastened to a spanwise spar with intermediate chordwise ribs, fractured during testing. Hinge-line deflection of the front spar was revealed. Through-thickness cracks in the forward and trailing edges of the compression-loading skin panel were revealed by nondestructive visual examination. A band of de-lamination between the areas of through-thickness skin fracture at the front and rear spar was revealed. A map of the local directions of crack propagation over the fracture surface was generated by the orientation of river patterns and resin microflow during microscopic examination of sectioned samples of the panel. It was discovered that crack initiation occurred at the periphery of a fastener hole located at the front spar. Propagation occurred chordwise across the compression-loaded skin panel. As a corrective measure, the fastener spacing was reduced to prevent the buckling mode that precipitated fracture.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.matlhand.c0089338
EISBN: 978-1-62708-224-2
Abstract
A steel lifting eye, manufactured from grade 1144 steel, failed during service. The eye ring fractured in two places, adjacent to the threaded shank and diametrically opposite to this region. Woody overload features, typical for resulfurized steels were revealed by SEM. The directionality of the features was found to be suggestive of shear overload. It was observed that fracture preferentially followed the nonmetallic inclusions. The fracture was revealed to be parallel to the direction of the manganese sulfide stringer inclusions. The presence of significant banding of the ferrite and pearlite microstructure was revealed by etching. It was also observed that the fracture is primarily along the inclusions and through bands of ferrite. It was concluded that the lifting eye failed as a result of overload. Fracture occurred parallel to the rolling direction, through manganese-sulfide stringers and ferrite bands in the base metal matrix. The material used for this application was very anisotropic, exhibiting substantially poorer long and short transverse mechanical properties than longitudinal properties.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.mech.c0089254
EISBN: 978-1-62708-225-9
Abstract
A failed tapered-ring sprocket locking device consisted of an assembly of four tapered rings that are retained by a series of cap screws. The middle wedge-shaped rings were pulled closer as the screws were tightened forcing the split inner ring to clamp tightly onto the shaft. One of the wedge-shaped middle rings fractured prior to having been fully torqued, preventing the sprocket from being locked to the shaft. “Woody” fracture features, as a result of decohesion between a high volume fractions of manganese sulfide stringers and the matrix, was revealed during examination. The material was revealed by chemical analysis to be resulfurized grade of carbon steel (SAE type 1144, UNS G11440) which has enhanced longitudinal tensile properties but low transverse properties. It was observed that when the fastening screws were torqued, a significant hoop stress was placed on the middle rings and it caused the failure at the large inclusion present at the minimum section thickness zone of the middle ring. It was concluded that since the material contained a high volume fraction of these inclusions, the material choice was not appropriate for this application. A nonresulfurized grade of low-alloy steel was suggested as recommendation.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.process.c9001421
EISBN: 978-1-62708-235-8
Abstract
The bottom flange of a vertical pipe coupled to an isolating valve in a steam supply line to a turbine failed. Steam pressure was 1,500 psi and the temperature 416 deg C (780 deg F). Multiple cracking occurred in the bore of the flange. A quarter-segment was cut out and examined. The cracks were located in the part of the flange that formed a continuation of the pipe bore. The majority of them originated at the end of the flange bore and extended axially along the pipe and radially across the flange face. Magnetic crack detection revealed a further number of cracks in the weld deposit. While the fracture in the weld metal was of the ductile type exhibiting a fine fibrous appearance, that in the flange material was of the cleavage type. Microscopic examination revealed that the cracks were blunt-ended fissures of the type characteristic of corrosion-fatigue. It was concluded that cracking was due to corrosion-fatigue, which arose from the combined effect of a fluctuating tensile stress in the presence of a mildly corrosive environment.
Book Chapter
Series: ASM Failure Analysis Case Histories
Publisher: ASM International
Published: 01 June 2019
DOI: 10.31399/asm.fach.conag.c0047479
EISBN: 978-1-62708-221-1
Abstract
A cast dragline bucket tooth failed by fracturing after a short time in service. The tooth was made of medium-carbon low-alloy steel heat treated to a hardness of 555 HRB. The fracture surface was covered with chevron marks. These converged at several sites on the surface of the tooth. A hardfacing deposit was located at each of these sites. Visual inspection of the hardfacing deposits revealed numerous transverse cracks, characteristic of many types of hardfacing. This failure was caused by cracks present in hardfacing deposits that had been applied to the ultrahigh-strength steel tooth. Given the small critical crack sizes characteristic of ultrahigh-strength materials, it is generally unwise to weld them. It is particularly inadvisable to hardface ultrahigh-strength steel parts with hard, brittle, crack-prone materials when high service stresses will be encountered. The operators of the dragline bucket were warned against further hardfacing of these teeth.
1