Effects of anisotropic pore structure and fiber texture on fatigue properties of lotus-type porous magnesium

2007 ◽  
Vol 22 (11) ◽  
pp. 3120-3129 ◽  
Author(s):  
H. Seki ◽  
M. Tane ◽  
H. Nakajima
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fracture Surface ◽  
Pore Structure ◽  
Longitudinal Axis ◽  
Fiber Texture ◽  
Fatigue Properties ◽  
Direction Parallel ◽  
Porous Magnesium

We studied the effects of anisotropic pores and fiber texture on the fatigue strength and fracture surface of lotus-type porous magnesium fabricated through unidirectional solidification in pressurized hydrogen and argon atmospheres. The fatigue strength in the direction parallel to the longitudinal axis of pores is higher than that in the perpendicular direction. Not only anisotropic pores but also fiber texture grown along the pore direction contributes to the anisotropy in the fatigue strength. The fatigue strength at finite life of lotus magnesium is closely related to the ultimate tensile strength; the fatigue strength is proportional to the ultimate tensile strength for both loadings parallel and perpendicular to the pore direction. The fracture surface of lotus magnesium is not flat, which originates from porous structure. For parallel loading, fiber texture in lotus magnesium also contributes to the irregular surface, i.e., a combination of texture and pore structure affects fracture surfaces.

Fatigue Strength of Lotus-Type Porous Magnesium

2007 ◽  
Vol 561-565 ◽  
pp. 1681-1684
Author(s):  
Hironori Seki ◽  
Masakazu Tane ◽  
Hideo Nakajima
Keyword(s):  
Fatigue Strength ◽  
Longitudinal Axis ◽  
Fiber Texture ◽  
Unidirectional Solidification ◽  
Perpendicular Direction ◽  
Direction Parallel ◽  
Cylindrical Pores ◽  
Porous Magnesium

We studied the fatigue strength of lotus-type porous magnesium with cylindrical pores aligned unidirectionally, which was fabricated through unidirectional solidification in pressurized hydrogen atmospheres. The fatigue strength shows anisotropy; the fatigue strength in the direction parallel to the longitudinal axis of pores is higher than that in the perpendicular direction. Not only anisotropic pores but also fiber texture grown along the pore direction contributes to the anisotropy in the fatigue strength.

Effects of pore morphology on fatigue strength and fracture surface of lotus-type porous copper

2007 ◽  
Vol 22 (5) ◽  
pp. 1331-1338 ◽  
Author(s):  
H. Seki ◽  
M. Tane ◽  
M. Otsuka ◽  
H. Nakajima
Keyword(s):  
Fatigue Strength ◽  
Fracture Surface ◽  
Applied Stress ◽  
Fatigue Behavior ◽  
Longitudinal Axis ◽  
Initiation Site ◽  
Pore Morphology ◽  
Direction Parallel ◽  
Stress Direction ◽  
Porous Copper

We studied the effect of anisotropic pore morphology on the fatigue behavior and fracture surface of lotus-type porous copper, which was fabricated through unidirectional solidification in pressurized hydrogen and argon atmospheres. The fatigue strength at finite life is closely related to the pore morphology. The fatigue strength decreases with increasing porosity, and the strength depends on applied-stress direction. The fatigue life is the longest in the direction parallel to the longitudinal axis of cylindrical pores. The fatigue strength at finite life is proportional to the ultimate tensile strength and can be expressed by a simple power-law formula. Anisotropic pores affect the fracture surface of lotus copper; crack-initiation site depends on applied-stress direction, and the anisotropic shape pores affect the direction of crack propagation and final fracture surface.

scholarly journals Fatigue Strength of Acacia Mangium

2019 ◽  
pp. 29-32
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Endurance Limit ◽  
Acacia Mangium ◽  
Vertical Axis ◽  
Life Cycles ◽  
Grain Angle ◽  
Sinusoidal Waveform ◽  
Fatigue Endurance

The works in this study is to investigate and understand the nature of Acacia mangium axial fatigue strengths under repeated stress. Acacia mangium trees were cut to produce oven-dried Small Clear Specimens that were then tested until fracture in parallel to the grain direction. This was carried out in order to discover its Ultimate Tensile Strength, which was later identified as 143.87 MPa, in parallel to the grain direction (0° grain angle). In the next phase, specimens were tested for fatigue strengths in repeated-tensile sinusoidal waveform loading at 100 Hz frequency. The stress levels for this test were at the ratios of 80, 60, 40, 30, 20 and 10% of the Ultimate Tensile Strength (0° grain angle) for the construction of Life (N) - Stress (S) plots and empirical correlation. It was observed that the Acacia Mangium N-S (Wöhler) plots have an exponential correlation with the N – intercept of vertical axis at five (5) million cycles, while the intercept of horizontal, S – axis, was at 143.87 MPa. The study also observed that Acacia mangium achieves 106 life cycles at 10% stress level. For this reason, it is concluded that the material has a fatigue endurance limit at 10% of the Ultimate Tensile Strength for 0° grain angle.

Fracture Behavior of an AlMgMnSc Alloy at Different Temperatures

2021 ◽  
Vol 1016 ◽  
pp. 292-296
Author(s):  
Yuliya Igorevna Borisova ◽  
Diana Yuzbekova ◽  
Anna Mogucheva
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Brittle Fracture ◽  
Fracture Surface ◽  
Strain Rate ◽  
Fracture Behavior ◽  
Fine Grained ◽  
Angular Pressing ◽  
Different Temperatures ◽  
Elongation To Failure

An Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (wt. %) alloy was studied in the fine-grained state obtaining after equal channel angular pressing. The mechanical behavior of alloy at the temperatures 173 K, 298 K and 348 K and at strain rate 1×10–3 s–1 is studied. Increase of the temperature testing from 173 K to 348 K decreases the yield stress by 80 MPa, the ultimate tensile strength by 60 MPa while elongation-to failure increases by a factor of 1.4. It was found that at temperatures of 298 and 173 K, the studied alloy mainly demonstrates the mode of ductile fracture, and at a temperature of 348 K the mechanism can be described as mixed ductile-brittle fracture. It was also established that of the studied alloy is the temperature dependence of the size of the dimples on the fracture surface. The formation of smaller dimples in the samples deformed at 298 K was observed.

Mechanical Properties and Fracture Study of Alumina Dispersion Hardened Copper-Based Nano-Composite at Elevated Temperatures

2013 ◽  
Vol 829 ◽  
pp. 583-588 ◽  
Author(s):  
Ali Dalirbod ◽  
Yahya A. Sorkhe ◽  
Hossein Aghajani
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Fracture Surface ◽  
Yield Strength ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Testing Temperature ◽  
Optical Microscope ◽  
Tensile Fracture ◽  
Different Temperatures

Alumina dispersion hardened copper-base composite was fabricated by internal oxidation method. The high temperature tensile fracture of Cu-Al2O3 composite was studied and tensile strengths were determined at different temperatures of 600, 680 and 780 °C. Microstructure was investigated by means of optical microscope and field emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS). Results show that, ultimate tensile strength and yield strength of copper alumina nanocomposite decrease slowly with increasing temperature. The yield strength reaches 119 MPa and ultimate tensile strength reaches 132 MPa at 780 °C. Surface fractography shows a dimple-type fracture on the fracture surface of the tensile tests where dimple size increases with increasing testing temperature and in some regions brittle fracture characteristics could be observed in the fracture surface.

The fatigue and ultimate tensile strengths of metals between 4⋅2 and 293° K

1957 ◽  
Vol 242 (1229) ◽  
pp. 203-211 ◽  
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Brittle Fracture ◽  
Low Temperatures ◽  
Fatigue Characteristics

The fatigue of copper, silver, gold, aluminium, magnesium, zinc and iron has been investigated at 4⋅2, 20, 90 and 293° K. Except for zinc and iron, which exhibit brittle fracture at low temperatures, the fatigue characteristics improve very considerably as the temperature is reduced. The ultimate tensile strength of all the metals was also taken at each temperature and there was shown to be a marked correlation between the increase in the tensile strength at low temperatures and the increase in the fatigue strength. The results are discussed with reference to current ideas on the mechanism of fatigue.

FATIGUE PROPERTIES OF AUTOMOBILE HIGH-STRENGTH BOLTS

2008 ◽  
Vol 22 (31n32) ◽  
pp. 5539-5544 ◽  
Author(s):  
CONGLING ZHOU ◽  
SHIN-ICHI NISHIDA ◽  
NOBUSUKE HATTORI
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Stress Level ◽  
High Strength ◽  
Fatigue Properties ◽  
Screw Thread ◽  
Mean Stress ◽  
Stress Levels ◽  
The Mean

This study is focused on the fatigue properties of automobile high-strength bolts, including the effect of mean stress level, pre-processing schedule and the residual stresses. And the mean stress levels are 0.3, 0.5 and 0.7 times to the tensile strength (σ B ) of the material respectively. The main results obtained are as follows: 1) the fatigue strength increases under the mean stress loading, but the differences between the loading levels are not so evident; 2) most of the cases in this study are broken from the bottom of the screw thread, and the crack initiated from the impurities.

scholarly journals The effect of temperature on fatigue strength and damage of FRP composite laminates

2021 ◽  
Author(s):  
Hossein Mivehchi
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Ultimate Tensile Strength ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Damage Model ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Frp Composites ◽  
Frp Composite

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

Experimental Investigation of Stratasys J750 PolyJet Printer: Effects of Orientation and Layer Thickness on Mechanical Properties

2019 ◽  
Author(s):  
Xingjian Wei ◽  
Abhinav Bhardwaj ◽  
Chin-Cheng Shih ◽  
Li Zeng ◽  
Bruce Tai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Elastic Modulus ◽  
Ultimate Tensile Strength ◽  
Layer Thickness ◽  
Axial Direction ◽  
Limited Information ◽  
Direction Parallel ◽  
Control Factors ◽  
Significant Difference

Abstract The J750 PolyJet printer is the newest model of full-color, multi-material 3D printer from Stratasys. Currently, limited information is available about the effects of control factors on mechanical properties such as elastic modulus, ultimate tensile strength, and elongation. In this study, the effects of two control factors, orientation and layer thickness, on mechanical properties of samples printed by the Stratasys J750 printer are investigated. The results show that orientation significantly affects mechanical properties. Specifically, samples printed with its axial direction parallel to the direction of printing have the highest elastic modulus, and elongation, whereas samples printed with its axial direction perpendicular to the direction of printing have the highest ultimate tensile strength. Also, layer thickness makes a significant difference for mechanical properties, and larger layer thickness leads to higher ultimate tensile strength and elongation. These results would be valuable to researchers and practitioners who use J750.

Effect of Plating Thickness on Fatigue Strength of Galvanized Steel

2020 ◽  
Vol 841 ◽  
pp. 3-8
Author(s):  
Kayo Hasegawa ◽  
Tatsuo Hayashi ◽  
Motoaki Morita ◽  
Shinichi Motoda
Keyword(s):  
Tensile Strength ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Main Crack ◽  
Immersion Time ◽  
Room Temperature ◽  
Columnar Structure ◽  
Galvanized Steel ◽  
Fatigue Properties ◽  
Plating Layer

Effect of the plating thicknesses on tensile and fatigue properties of hot-dip galvanized steel at room temperature was evaluated. The galvanized steel with thickness of 100 μm and 200 μm were prepared. Both microstructures of η-phase and δ1-phase were similar with each other. In the comparison with the galvanized steel with thickness of 100 μm, the microstructure of ζ-phase for the galvanized steel with thickness of 200 μm was blunt columnar structure due to long immersion time. Tensile and fatigue strengths for a galvanized steel are sensitive to the microstructure of the galvanized layer. The tensile strength and the strength of fatigue limit for the galvanized steel with thickness of 200 μm were smaller than that of 100 μm. In the galvanized steel with thickness of 200 μm, the peeling at plating layer easily occurred. The exfoliated sites have the potential to become subcracks. As the result, the main crack may propagate at early cycles.

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