scholarly journals A Review on the Mechanisms and Analysis of Fatigue in Ductile Materials

2021 ◽  
Author(s):  
Amal A ◽  
Mohammed Thowsif
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Performance ◽  
Structural Performance ◽  
Cyclic Loads ◽  
Key Factors ◽  
Engineering Structure ◽  
Ductile Materials ◽  
Engineering Component ◽  
Load Pattern

In civil engineering, fatigue can be referred to as the loss in structural performance of engineering components when subjected to repeated cyclic loads. Fatigue is identified as one of the leading factors that determines the lifespan of an engineering structure. Fatigue develops in the form of small and localized cracks which gradually propagates subcritically until the engineering component is structurally incapable to satisfy the serviceability conditions and ultimately fails. Due to the engineering importance of the phenomenon, fatigue is studied extensively in order to obtain a better understanding of the phenomenon and its manifestation in different engineering components. Over the years a number of mechanisms and models have been developed in order to explain, analyze and predict the effects of the phenomenon on various components. The three key factors that have been identified to have influenced the fatigue life of engineering components include the material properties of the engineering component, the geometry of the engineering component and the load pattern to which the engineering component is subjected. This paper aims to give a brief and consolidated overview of the various mechanisms, the different models and the influence of the various factors on the fatigue performance of components composed of ductile materials.

scholarly journals Lifetime Assessment and Optimization of a Welded A-Type Frame in a Mining Truck Considering Uncertainties of Material Properties and Structural Geometry and Load

2019 ◽  
Vol 9 (5) ◽  
pp. 918 ◽  
Author(s):  
Chengji Mi ◽  
Wentai Li ◽  
Xuewen Xiao ◽  
Haigen Jian ◽  
Zhengqi Gu ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Material Properties ◽  
Optimal Solution ◽  
Collaborative Optimization ◽  
Fatigue Performance ◽  
Dynamics Simulation ◽  
Nsga Ii ◽  
Element Analysis ◽  
Material Parameters

Abstract: In order to improve the fatigue performance of a welded A-type frame in a heavy off-road mining truck, a novel method was presented to implement lifetime and weight collaborative optimization while considering uncertainties in geometry dimension, material properties, and bearing load. The mechanical and cyclic material parameters were obtained from experimental work to characterize the base metal and the weldment. The finite element model of a welded A-type frame was constructed to analyze stress distribution and predict fatigue life, the force time histories of which were acquired from multi-body dynamics simulation. The simulated failure position and fatigue life had a good agreement with the actual results. Then, both structural lifetime and weight were considered as optimization objectives. The thickness of main steel plates and elastic and cyclic material parameters were chosen as uncertain design variables as well as main loads at connection locations. The fifty sample points in the light of Latin hypercube sampling method and its responses calculated by finite element analysis were supposed to build the approximation model based on the Kriging approximation method. After its fitting precision was guaranteed, the non-dominated sorting genetic algorithm II (NSGA-II) was utilized to find the optimal solution. Finally, the fatigue life of a welded A-type frame was increased to 2.40×105 cycles and its mass was lessened by 8.2%. The optimized results implied that good fatigue performance of this welded A-type frame needs better welding quality, lower running speed for downhill and turning road surface, and thicker front plates.

Robust Design for Fatigue Performance: Shot Peening

1996 ◽  
Author(s):  
Marcos Esterman ◽  
Ivan M. Nevarez ◽  
Kosuke Ishii ◽  
Drew V. Nelson
Keyword(s):  
Fatigue Life ◽  
Surface Treatment ◽  
Robust Design ◽  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Fatigue Performance ◽  
Quality Characteristic ◽  
Design Parameters ◽  
Line Production

Abstract Fatigue data usually display substantial scatter. The goal of this paper is to demonstrate how simulated variation in surface treatment processing parameters and material properties affect the predicted fatigue life (mean and scatter) of a component. This is achieved by applying robust design principles to fatigue life evaluation methods, using shot peening as the representative manufacturing process for this study. Analyzing changes in the appropriate fatigue performance quality characteristic due to variations in the process parameters and material properties will identify levels of the controllable process parameters which maximize the mean fatigue performance and minimize its scatter. The simulation predictions of this study are consistent with past experimental observations which show that compressive residual stress distributions tend to increase mean fatigue life and reduce its scatter for a component. Our results extend these observations by relating the increase in mean life and the reduction in scatter to the controllable manufacturing and design parameters. In addition, the intermediate measure of compressive zone depth is identified as a possible off-line production quality check that relates directly to the component fatigue performance (mean and scatter), as well as an aid to the designer to identify an appropriate surface treatment process. This study serves as an initial step in the development of a generalized methodology that can aid engineers with design for robust fatigue performance for other manufacturing processes.

scholarly journals Review on Factors Governing Stress Concentration Factor at Tubular Joints

2021 ◽  
Author(s):  
Gemi Maria Mathews ◽  
Althaf M
Keyword(s):  
Fatigue Life ◽  
Stress Concentration ◽  
Fatigue Damage ◽  
Stress Concentration Factor ◽  
Crucial Role ◽  
Concentration Factor ◽  
Structural Performance ◽  
Cyclic Loads ◽  
Tubular Structures ◽  
Tubular Joints

Tubular structures have become so much in use because of their structural performance and attractive appearance. But at the intersections of these tubular structures (i.e., tubular joints), there is stress concentration which adds the fatigue damage in structures which is exposed to cyclic loads. The stress concentration factor plays a crucial role in the computation of fatigue life of tubular structures exposed to cyclic loads. This paper aims to review the factors governing stress concentration factor at tubular joints.

Low-Cycle Fatigue Performance of Buckling Restrained Braces and Assessment of Cumulative Damage under Severe Earthquakes

2018 ◽  
Vol 763 ◽  
pp. 867-874
Author(s):  
Yu Shu Liu ◽  
Ke Peng Chen ◽  
Guo Qiang Li ◽  
Fei Fei Sun
Keyword(s):  
Fatigue Life ◽  
Energy Dissipation ◽  
Structural Reliability ◽  
Low Cycle Fatigue ◽  
Engineering Application ◽  
Fatigue Performance ◽  
Cycle Fatigue ◽  
Variable Amplitude ◽  
Buckling Restrained Braces ◽  
Energy Dissipation Devices

Buckling Restrained Braces (BRBs) are effective energy dissipation devices. The key advantages of BRB are its comparable tensile and compressive behavior and stable energy dissipation capacity. In this paper, low-cycle fatigue performance of domestic BRBs is obtained based on collected experimental data under constant and variable amplitude loadings. The results show that the relationship between fatigue life and strain amplitude satisfies the Mason-Coffin equation. By adopting theory of structural reliability, this paper presents several allowable fatigue life curves with different confidential levels. Besides, Palmgren-Miner method was used for calculating BRB cumulative damages. An allowable damage factor with 95% confidential level is put forward for assessing damage under variable amplitude fatigue. In addition, this paper presents an empirical criterion with rain flow algorithm, which may be used to predict the fracture of BRBs under severe earthquakes and provide theory and method for their engineering application. Finally, the conclusions of the paper were vilified through precise yet conservative prediction of the fatigue failure of BRB.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

Influence of Wear Properties on Fretting Fatigue Life of a CK45 Alloy and the Al7175 Alloy

2008 ◽  
Vol 587-588 ◽  
pp. 971-975 ◽  
Author(s):  
M. Buciumeanu ◽  
A.S. Miranda ◽  
F.S. Silva
Keyword(s):  
Wear Resistance ◽  
Fatigue Life ◽  
Material Properties ◽  
Fatigue Behavior ◽  
Synergetic Effect ◽  
Fretting Fatigue ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
Wear Properties

The main objective of this work was to study the influence of the wear properties of two commercial alloys (CK45 and Al7175) on their fretting fatigue behavior. It is verified the effect of material local degradation by wear on a fatigue strength reduction factor, namely the stress concentration factor, and on the overall fretting fatigue life of these materials. The fretting fatigue phenomenon is a synergetic effect between wear and fatigue. It is dependent on both the fatigue and the wear properties of the materials. Material properties promoting an increase in wear resistance should enhance fretting fatigue life.

Flexural Fatigue Performance of RC Beams Strengthened with Hybrid Fiber Sheets

2012 ◽  
Vol 166-169 ◽  
pp. 1657-1662
Author(s):  
Xu Jun Chen ◽  
Xiao E Zhu ◽  
Zhong Yang ◽  
Mu Xiang Dai
Keyword(s):  
Fatigue Life ◽  
Basalt Fiber ◽  
Reinforced Concrete Beams ◽  
Fatigue Performance ◽  
Rc Beam ◽  
Rc Beams ◽  
Hybrid Fiber ◽  
Cycle Number ◽  
Flexural Fatigue ◽  
Variation Characteristics

Based on the fatigue test for flexural performance of five reinforced concrete beams, the variation characteristics of the crack development, concrete strain, steel strain, fiber strain with the cycle number of the fatigue load were analyzed, and the effect of hybrid fiber sheets and basalt fiber reinforced polymer(BFRP)sheets on flexural fatigue performance of the strengthened beam was studied. The results show that the accumulated damage of RC beams strengthened with hybrid fiber sheets was slowed down significantly, the anti-crack property was much improved, and the fatigue life was greatly prolonged. Compared with the ordinary RC beam and the RC beam strengthened with double BFRP sheets, the fatigue life of RC beams strengthened with hybrid CFRP/BFRP(C/BFRP) sheets and hybrid CFRP/GFRP(C/GFRP) sheets was increased by 291.26%, 298.63% and 10.73%, 13.53%.

scholarly journals Fatigue Performance and Multiscale Mechanisms of Concrete Toughened by Polymers and Waste Rubber

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Bo Chen ◽  
Liping Guo ◽  
Wei Sun
Keyword(s):  
Fatigue Life ◽  
Polyvinyl Alcohol ◽  
Water Soluble ◽  
Fatigue Performance ◽  
Tire Rubber ◽  
Bending Fatigue ◽  
Waste Tire ◽  
Waste Rubber ◽  
Bonding Effect ◽  
Waste Tire Rubber

For improving bending toughness and fatigue performance of brittle cement-based composites, two types of water-soluble polymers (such as dispersible latex powder and polyvinyl alcohol powder) and waste tire-rubber powders are added to concrete as admixtures. Multiscale toughening mechanisms of these additions in concretes were comprehensively investigated. Four-point bending fatigue performance of four series concretes is conducted under a stress level of 0.70. The results show that the effects of dispersible latex powder on bending toughness and fatigue life of concrete are better than those of polyvinyl alcohol powder. Furthermore, the bending fatigue lives of concrete simultaneously containing polymers and waste rubber powders are larger than those of concrete with only one type of admixtures. The multiscale physics-chemical mechanisms show that high bonding effect and high elastic modulus of polymer films as well as good elastic property and crack-resistance of waste tire-rubber powders are beneficial for improving bending toughness and fatigue life of cementitious composites.

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