scholarly journals Cumulative Fatigue damage of AA7075-T6 under Shot Peening and Ultrasonic Surface Treatments

2021 ◽  
Vol 14 (1) ◽  
pp. 1-10
Author(s):  
Marwa S. Mahammed ◽  
Hussain J. Alalkawi ◽  
Saad T. Faris
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Damage ◽  
Shot Peening ◽  
Endurance Limit ◽  
Mechanical Design ◽  
Ultrasonic Impact Treatment ◽  
Sample Group ◽  
Cumulative Fatigue Damage ◽  
Fatigue Endurance

One of the important aspects of mechanical design is improving fatigue life.; In this work, the effect of Ultrasonic impact treatment (UIP) and shot peening (SP)on constant cumulative fatigue life and fatigue strength of AA7075-T6 were studied; The sample group was machined and primed, and some specimens were treated using ultrasonic impact therapy (UIT) with one line of peening. Fatigue experiments were conducted under constant and variable amplitude (R=-1) at ambient temperature to determine the fatigue life of the S-N curve and fatigue strength during treatment 3.46% and 8.57% at 107 cycles for (UIT) and (SP). Cumulative fatigue damage testing was carried out for two steps loading it is observed that the fatigue life for SP and UIP treated specimens was improved compared to the unpeeled results. The fatigue endurance limit was enhanced by 35% for UIT and 54% for SP. The fatigue life for both treatments was much improved compared to as-received metal. These results also show a strong tendency of increasing fatigue strength after application of (UIT) and (SP) with an increase in mechanical properties of the material used.

scholarly journals Investigation on Influence of Ultrasonic Impact Treatment (UIT) on Fatigue Life for Aluminium Alloy 2017-T4

2018 ◽  
Vol 21 (1) ◽  
pp. 141 ◽  
Author(s):  
Hussain J. M. Alalkawi ◽  
Aseel A. Alhamdany ◽  
Marib R. Abdul Hassan
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Ambient Temperature ◽  
Aluminium Alloy ◽  
Mechanical Design ◽  
Fatigue Tests ◽  
Strong Tendency ◽  
Ultrasonic Impact Treatment ◽  
Variable Amplitude

Improving fatigue life is one of the most important issues in mechanical design; an investigation has been conducted on Al 2017-T4. Group of samples have been machined and prepared, some of specimens have been treated using the ultrasonic impact treatment (UIT) with one line peening. The fatigue tests were carried out under constant and variable amplitude (R=-1) at ambient temperature, in order to find out the fatigue life S-N curve and strength after treatment. It has been found significant increasing in strength after it was treated by (UIT).  The fatigue strength is improved after treatment up to 4.16% at 107 cycles, enhancement are present with 24% and 18.78% for the cumulative fatigue lives low-high and high–low respectively.  These results also show a strong tendency of increasing of fatigue strength after application of (UIT) with increase in mechanical properties of material used.

scholarly journals Improvement of Fatigue Property in High Strength Aluminum Alloy by Shot Peening

2012 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Hussain J.Al-Alkawi ◽  
Mohammed J.Kadhim
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Life ◽  
Shot Peening ◽  
Endurance Limit ◽  
Fatigue Behavior ◽  
Fatigue Property ◽  
High Strength ◽  
High Strength Aluminum Alloy ◽  
Before And After ◽  
Cumulative Fatigue Damage

Shot peening process has both the beneficial and detrimentaleffects; therefore, it is difficult and time–consuming task to determine the optimized process parameters based on the fatiguelife. In this study the fatigue of 7001-T6 high strength aluminum alloy has been investigate before and after a shot peeningis beneficial for a treatment to investigate where a shot peening is beneficial for a component with this combination. The effect of 12 min. shot peening on the fatigue behavior of the material used gave an increase in the fatigue life of up to 2.49 times depending on the applied stress, and a 28.34% increase in the endurance limit of the material. Cumulative fatigue damage was conducted under low-high and high-low stress amplitude .The fatigue life prolonging factor (FLPF) was calculated for different stress amplitudes and it was found that this parameter is an indicator for prolonging the fatigue life.

Fatigue Life Improvement of Welded Elements and Structures by Ultrasonic Impact Treatment

2011 ◽  
Author(s):  
Yuriy Kudryavtsev ◽  
Jacob Kleiman
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Fatigue Testing ◽  
Highway Bridges ◽  
Surface Layers ◽  
Ultrasonic Impact Treatment ◽  
Stress Relieving ◽  
Life Improvement

The ultrasonic impact treatment (UIT) is relatively new and promising process for fatigue life improvement of welded elements and structures. In most industrial applications this process is known as ultrasonic peening (UP). The beneficial effect of UIT/UP is achieved mainly by relieving of harmful tensile residual stresses and introducing of compressive residual stresses into surface layers of a material, decreasing of stress concentration in weld toe zones and enhancement of mechanical properties of the surface layers of the material. The UP technique is based on the combined effect of high frequency impacts of special strikers and ultrasonic oscillations in treated material. Fatigue testing of welded specimens showed that UP is the most efficient improvement treatment as compared with traditional techniques such as grinding, TIG-dressing, heat treatment, hammer peening and application of LTT electrodes. The developed computerized complex for UP was successfully applied for increasing the fatigue life and corrosion resistance of welded elements, elimination of distortions caused by welding and other technological processes, residual stress relieving, increasing of the hardness of the surface of materials. The UP could be effectively applied for fatigue life improvement during manufacturing, rehabilitation and repair of welded elements and structures. The areas/industries where the UP process was applied successfully include: Shipbuilding, Railway and Highway Bridges, Construction Equipment, Mining, Automotive, Aerospace. The results of fatigue testing of welded elements in as-welded condition and after application of UP are considered in this paper. It is shown that UP is the most effective and economic technique for increasing of fatigue strength of welded elements in materials of different strength. These results also show a strong tendency of increasing of fatigue strength of welded elements after application of UP with the increase in mechanical properties of the material used.

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.

Fatigue Life Assessment of Crane Reel

2011 ◽  
Vol 383-390 ◽  
pp. 2941-2944
Author(s):  
Wei Ming Du ◽  
Fei Xue
Keyword(s):  
Finite Element Method ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Residual Life ◽  
Life Assessment ◽  
Life Estimation ◽  
Fatigue Life Assessment ◽  
Weld Fatigue ◽  
Simulation Results ◽  
Cumulative Fatigue Damage

The crane reel is generally manufactured by section welding method when the diameter is over 380mm. With the cumulative fatigue damage principle which is based on stress S-N curve, the fatigue damage of one crane reel is analyzed by finite element method, the reel weld fatigue strength and fatigue life are calculated, and the simulation results are proved to be reliable. This method provides an efficient reference for crane reel design and residual life estimation.

The Effect of Shot Peening on the Surface Topography and Fatigue Strength of Selected Sheets

2015 ◽  
Vol 818 ◽  
pp. 19-22
Author(s):  
Łukasz Bąk ◽  
Magdalena Bucior ◽  
Felix Stachowicz ◽  
Władysław Zielecki
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Shot Peening ◽  
Experimental Tests ◽  
Special Treatment ◽  
Surface Layers ◽  
Impact Bending ◽  
Improve Fatigue Strength ◽  
Compressive Residual Stresses ◽  
Improve Fatigue

Numerous investigations have been performed in an attempt to improve fatigue strength of materials by creating compressive residual stresses in the surface layers as a result of the shot peening process. For example, during exploitation of the separating screener, some parts of screen sieve plate situated near the fixed edge undergo the largest deformation caused by impact bending and need special treatment. In this paper, the results of experimental tests are presented to analyse the effect of micro shot peening on surface layer characteristics and fatigue strength of steel sheet specimens. The effect of shot peening is more visible when fatigue life is taking into account. Thus, the use of shot peening of sheet surface made it possible to increase fatigue life of screener sieve.

Nonlinear Cumulative Fatigue Damage Model

2011 ◽  
Vol 328-330 ◽  
pp. 1440-1444
Author(s):  
Hua Zou ◽  
Qiang Li ◽  
Shou Guang Sun
Keyword(s):  
Mathematical Model ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Welded Joint ◽  
Damage Model ◽  
Reasonable Explanation ◽  
Curve Method ◽  
Cumulative Fatigue Damage ◽  
Damage Rule

Cumulative fatigue damage is an important consideration in determining the fatigue life of structures. A cumulative linear damage rule cannot provide a reasonable explanation for cumulative fatigue damage, but a damage curve method based on nonlinear cumulative fatigue damage model can give a reasonable explanation. In this paper, a specific mathematical model is put forward, which is based on the damage curve method. In the model, miner formula is modified properly and an exponent formula is give out to fit the damage accumulate. According to a two-step fatigue test of aluminum–alloy welded joint, the comparison between the calculated results and the testing results is less than 5%. It shows that the model is reasonable and accuracy.

Surface Integrity and Fatigue Strength of Hard Milled Surfaces

2011 ◽  
Author(s):  
W. Li ◽  
Y. B. Guo ◽  
M. E. Barkey ◽  
C. Guo ◽  
Z. Q. Liu
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Surface Integrity ◽  
Endurance Limit ◽  
Flank Wear ◽  
Machining Accuracy ◽  
Tool Flank Wear ◽  
Radial Depth ◽  
Aisi H13 Tool Steel ◽  
Machined Surfaces

Tool flank wear during hard milling adversely affects surface integrity and, therefore, fatigue strength of machined components. Surface integrity and machining accuracy deteriorate when tool wear progresses. In this paper, surface integrity and its impact on endurance limit of AISI H13 tool steel (50 ± 1 HRC) by milling using PVD coated tools are studied. The evolutions of surface integrity including surface roughness, microhardness and microstructure were characterized at three levels of tool flank wear (VB = 0, 0.1mm, 0.2mm). At each level of tool flank wear, the effects of cutting speed, feed, and radial depth-of-cut on surface integrity were investigated respectively. Fatigue endurance limits of the machined surfaces at different reliability levels were calculated and correlated with the experimentally determined fatigue life. The good surface finish and significant strain-hardening on the machined surfaces enhance endurance limit, which enables machined components have a fatigue life over 106 cycles.

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