Effect of CO2 Saturation and Desorption on the Fatigue Life of Polycarbonate

1994 ◽  
Vol 116 (4) ◽  
pp. 451-456 ◽  
Author(s):  
K. A. Seeler ◽  
Vipin Kumar
Keyword(s):  
Shear Strength ◽  
Fatigue Life ◽  
Yield Strength ◽  
Fatigue Cracks ◽  
Saturation Pressure ◽  
Stress Relief ◽  
Shear Fatigue ◽  
Static Yield ◽  
Swelling Strain ◽  
Slow Growing

The effect of a cycle of CO2 saturation and desorption on the yield strength, Young’s modulus, and fatigue life of polycarbonate was investigated. The fatigue life of the saturation-cycled polycarbonate exceeded that of unprocessed polycarbonate by up to a factor of thirty. The fatigue life of these rough-surfaced saturation-cycled specimens was approximately equal to or greater than that of polished smooth bar specimens. The increase in fatigue life is a function of the CO2 saturation pressure, reaching a maximum at the same saturation pressure at which there is no further reduction in static yield strength. The increased fatigue life is hypothesized to result from one or more of following mechanisms: (1) reduction of shear strength promoting slow-growing shear fatigue cracks: (2) “healing” or blunting of pre-existing flaws or microcracks by swelling strain or by stress relief strain resulting from plasticization by CO2 during saturation.

scholarly journals Effect of Repetitive Collar Replacement on the Residual Strength and Fatigue Life of Retained Hi-Lok Fastener Pins

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 445 ◽  
Author(s):  
David F. Hardy ◽  
David L. DuQuesnay
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Fatigue Life ◽  
Failure Mode ◽  
Residual Strength ◽  
Clamping Force ◽  
Ultimate Shear Strength ◽  
Shear Fatigue ◽  
Static Tensile ◽  
Static Shear

Hi-Lok fasteners were subjected to multiple collar replacements, and were tested under static loading and constant-amplitude fatigue loading, to determine the effect of repetitive collar replacement on the residual strength and fatigue life of a retained Hi-Lok-type fastener pin. Hi-Lok-type fasteners are typically used in aircraft structural joints, and are loaded mainly in shear. Tests were conducted for clamping force, static shear strength, static tensile strength, and shear fatigue life for collars subjected to five collar replacements. The static shear results showed no decrease in the ultimate shear strength of the fastener pin as a function of collar replacement. Static tensile results showed no decrease in the ultimate tensile strength of the fastener as a function of collar replacement, with failure of the aluminum collar remaining the critical failure mode. Similarly, shear fatigue results showed no decrease in the shear fatigue life of the fastened joint as a result of collar replacement, with fracture of the aluminum substrate remaining the critical failure mode. For static shear, static tension, and shear fatigue tests, estimated clamping force was highly consistent between specimens and no decrease in clamping force was observed as a function of collar replacement.

scholarly journals Shear Fatigue Performance of Epoxy Resin Waterproof Adhesive Layer on Steel Bridge Deck Pavement

2021 ◽  
Vol 7 ◽  
Author(s):  
Ying Xu ◽  
Xinpeng Lv ◽  
Chunfeng Ma ◽  
Fengming Liang ◽  
Jiafei Qi ◽  
...  
Keyword(s):  
Shear Strength ◽  
Fatigue Life ◽  
Epoxy Resin ◽  
Bridge Deck ◽  
Adhesive Layer ◽  
Fatigue Performance ◽  
Steel Bridge ◽  
Shear Fatigue ◽  
Interlaminar Shear ◽  
Bridge Deck Pavement

In this study, the effects of temperature, shear stress, and coating quantity of waterproof adhesive layer on the shear fatigue performance of a steel bridge deck pavement were investigated. Direct shear fatigue tests of a pavement comprising an epoxy resin waterproof adhesive layer with stone matrix asphalt were conducted at different temperatures, stress levels, and coating quantities. The results show that temperature and stress have significant effects on the shear fatigue life. With increasing temperature and stress, the shear fatigue life of the waterproof adhesive layer decreased gradually. Therefore, for steel bridge deck pavements under high temperatures and heavy loads, the use of asphalt waterproof adhesive layers or pavement layers should be evaluated carefully while limiting the traffic of heavily loaded vehicles. Shear failure occurs at the waterproof adhesive layer–pavement interface and not at the steel–waterproof adhesive layer interface. The shear strength of the epoxy resin waterproof adhesive layer is mainly provided by the bond strength between the waterproof adhesive and pavement mixture as well as the interlocking force between the cured epoxy resin and the bottom interface of uneven pavement mixture. The shear strength increases with the coating quantity of the waterproof adhesive layer; however, after reaching the maximum value, the shear strength becomes stable. In contrast, the interlaminar shear fatigue life increases continuously with the coating quantity of the waterproof adhesive layer. Appropriately increasing the coating quantity is beneficial for improving the resistance of the waterproof adhesive layer to interlaminar shear fatigue failure.

MAGNESIUM MSR-B

Alloy Digest ◽  
1967 ◽  
Vol 16 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Shear Strength ◽  
High Temperature ◽  
Magnesium Alloy ◽  
Yield Strength ◽  
Physical Properties ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cast Magnesium Alloy ◽  
Cast Magnesium

Abstract Magnesium MSR-B is a heat-treatable magnesium alloy with highest yield strength of any cast magnesium alloy up to 480 F. It is pressure tight and weldable by argon-arc. It is recommended for aircraft nose wheels, missile components, transmission cases, etc. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Mg-63. Producer or source: Magnesium Elektron Ltd.

RUUKKI RAEX 300

Alloy Digest ◽  
2012 ◽  
Vol 61 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
Shear Strength ◽  
Impact Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Structural Components ◽  
Wear Resistant

Abstract RUUKKI RAEX 300 (typical yield strength 900 MPa) is part of the Raex family of high-strength and wear-resistant steels with favorable hardness and impact toughness to extend life and decrease wear in structural components. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on wear resistance as well as forming, machining, and joining. Filing Code: SA-643. Producer or source: Rautaruukki Corporation.

HISTAR 355

Alloy Digest ◽  
2015 ◽  
Vol 64 (9) ◽  
Keyword(s):  
Fracture Toughness ◽  
Shear Strength ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
Low Temperatures ◽  
High Yield ◽  
High Yield Strength

Abstract Histar 355 is a structural steel combining high yield strength (355 MPa minimum) with excellent toughness at low temperatures and outstanding weldability. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear strength as well as fracture toughness. It also includes information on forming, machining, and joining. Filing Code: SA-731. Producer or source: ArcelorMittal and ArcelorMittal Luxembourg.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

A new approach for pre-stressing of rail-end-bolt holes

2016 ◽  
Vol 231 (12) ◽  
pp. 2275-2283 ◽  
Author(s):  
JT Maximov ◽  
GV Duncheva ◽  
IM Amudjev ◽  
AP Anchev ◽  
N Ganev
Keyword(s):  
Fatigue Life ◽  
Fatigue Cracks ◽  
New Technology ◽  
Innovative Technology ◽  
Bolted Joint ◽  
Compressive Stresses ◽  
Process Formation ◽  
Technology Process ◽  
Bolt Holes ◽  
Hoop Stresses

Bolted joint railroad is the subject matter of this paper. Rail joint elements are subjected to cyclic and impact loads as a result of the passage of trains, which causes the origination and growth of fatigue cracks occurring, in most cases, around the bolt holes. Fatigue failure around rail-end-bolt holes is particularly dangerous because it leads to derailment of trains and, consequently, to inevitable accidents. Moreover, the cracking at rail-ends, which starts from bolt hole surface, causes premature rails replacement. The presence of residual compressive hoop stresses around the bolted holes, which is achieved by prestressing of these holes, extends the fatigue life of bolted joint railroads. This article presents an innovative technology for pre-stressing of rail-end-bolt holes, implemented on a vertical machining centre of Revolver vertical (RV) type. Two consecutive operations are involved in the manufacturing technology process: formation of the hole by drilling, reaming and making of a chamfer through a new combined cutting tool; cold hole working by spherical motion cold working through a new tool equipment, which minimizes the axial force on the reverse stroke. The new technology introduces beneficial residual compressive stresses around the bolted holes thereby preventing the fatigue cracks growth and increasing the fatigue life of these openings.

scholarly journals Structural and mechanical defects of materials of offshore and onshore main gas pipelines after long-term operation

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Pavlo Maruschak ◽  
Sergey Panin ◽  
Iryna Danyliuk ◽  
Lyubomyr Poberezhnyi ◽  
Taras Pyrig ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Quantitative Analysis ◽  
Stress Concentration ◽  
Cyclic Loading ◽  
Fatigue Cracks ◽  
Preliminary Deformation ◽  
Term Operation ◽  
Steel Pipes

AbstractThe study has established the main regularities of a fatigue failure of offshore gas steel pipes installed using S-lay and J-lay methods.We have numerically analyzed the influence of preliminary deformation on the fatigue life of 09Mn2Si steel at different amplitudes of cyclic loading. The results have revealed the regularities of formation and development of a fatigue crack in 17Mn1Si steel after 40 years of underground operation. The quantitative analysis describes the regularities of occurrence and growth of fatigue cracks in the presence of a stress concentration.

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