Deep Rolling Efficiently Increases Fatigue Life

2005 ◽  
Author(s):  
Karsten Ro¨ttger ◽  
Terry L. Jacobs ◽  
Gerhard Wilcke
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Stainless Steels ◽  
Manufacturing Process ◽  
Nickel Alloys ◽  
Lightweight Design ◽  
Surface Zone ◽  
Tool Steels ◽  
Deep Rolling ◽  
Alloy Steels

Deep rolling is a manufacturing process that efficiently increases the fatigue life of dynamically loaded components. It combines three effects to enhance fatigue strength, tribological properties and corrosion of a surface. Deep rolling: • Smoothes the surface; • Induces deep compressive stress in the surface zone; • Work-hardens the surface zone. The technology has developed into a modern, widely applicable process that improves part performance and achieves lightweight design. It has successfully been applied on stainless steels, alloy steels, brass, tool steels, nickel alloys, cast and ductile irons, aluminum, magnesium and titanium alloys [1,2,3].

Proposal of Fatigue Life Equations for Carbon and Low-Alloy Steels and Austenitic Stainless Steels as a Function of Tensile Strength

2013 ◽  
Author(s):  
Hiroshi Kanasaki ◽  
Makoto Higuchi ◽  
Seiji Asada ◽  
Munehiro Yasuda ◽  
Takehiko Sera
Keyword(s):  
Tensile Strength ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Room Temperature ◽  
Austenitic Stainless Steels ◽  
Low Alloy Steels ◽  
Strength Based ◽  
Fatigue Data ◽  
Current Design ◽  
Alloy Steels

Fatigue life equations for carbon & low-alloy steels and also austenitic stainless steels are proposed as a function of their tensile strength based on large number of fatigue data tested in air at RT to high temperature. The proposed equations give a very good estimation of fatigue life for the steels of varying tensile strength. These results indicate that the current design fatigue curves may be overly conservative at the tensile strength level of 550 MPa for carbon & low-alloy steels. As for austenitic stainless steels, the proposed fatigue life equation is applicable at room temperature to 430 °C and gives more accurate prediction compared to the previously proposed equation which is not function of temperature and tensile strength.

Fatigue Strength of Ribbon Bonds

2010 ◽  
Author(s):  
S. M. Bresney ◽  
A. Saigal
Keyword(s):  
Thermal Expansion ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Manufacturing Process ◽  
Electronic Components ◽  
Mechanical Method ◽  
Temperature Changes ◽  
Life Model ◽  
Short Span ◽  
Different Levels

Ribbon or wire bonding is a common manufacturing process used in the microelectronic industry to make interconnections between electronic components. This process is used because it can make up for misalignment and inconsistent spacing between the components due to tolerance stack ups. In addition, since the ribbons are not rigid they will flex and absorb any stresses that develop when the components expand and contract in the field due to temperature changes. This paper investigates the use of a mechanical method to exercise ribbons in this fashion until they failed. Ribbons of a constant profile but different sizes were exercised at different levels of stress to develop a fatigue life model. It is found that ribbons exercised only a small percentage of their overall span survive exponentially longer than the same ribbons exercised at a higher percentage of their overall span. In addition, at short span lengths relative to the thickness, the ribbon becomes less ‘thread like’ and more stiff. The model developed in this study can be used for designing ribbon size and shape based upon expected thermal expansion cycling and necessary life or reliability.

scholarly journals Weldment to Casting Conversion Using Topology Optimization

2021 ◽  
Vol 9 (8) ◽  
pp. 1309-1319
Author(s):  
Prasad Kulkarni
Keyword(s):  
Topology Optimization ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Dimensional Stability ◽  
Manufacturing Process ◽  
Traditional Method ◽  
Design For Manufacturability ◽  
Final Design ◽  
The Cost ◽  
Casting Design

Abstract: The automobile and off highway industries grapple with dilemma of making a required component out of a weldment by welding different plates together or making a single component using a casting manufacturing process. The decision is always based on many parameters viz. volume of manufactured components, tooling cost involved, dimensional stability required, cost of welding, fatigue strength required etc. As the volume of the manufactured components increases, the cost of casting and its tool goes down and hence it makes sense to convert the weldment into a casting. A traditional method to do this is to convert the weldment into a casting based on functionalities and experience. In this paper, a topology optimization based approach is used to understand and decide the most optimal usage of the material based on the different constraints. In this paper, considerations of weldment to casting conversion, usage of topology optimization to arrive at final design and strength and fatigue life calculation are discussed. Keywords: Weldment, Topology Optimization, casting, Design for Manufacturability

scholarly journals Fatigue Modeling and Numerical Analysis of Re-Filling Probe Hole of Friction Stir Spot Welded Joints in Aluminum Alloys

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2171
Author(s):  
Armin Yousefi ◽  
Ahmad Serjouei ◽  
Reza Hedayati ◽  
Mahdi Bodaghi
Keyword(s):  
Experimental Data ◽  
Tensile Strength ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Fatigue Behavior ◽  
Element Model ◽  
Plastic Strain Amplitude ◽  
Friction Stir ◽  
Probe Hole ◽  
Good Agreement

In the present study, the fatigue behavior and tensile strength of A6061-T4 aluminum alloy, joined by friction stir spot welding (FSSW), are numerically investigated. The 3D finite element model (FEM) is used to analyze the FSSW joint by means of Abaqus software. The tensile strength is determined for FSSW joints with both a probe hole and a refilled probe hole. In order to calculate the fatigue life of FSSW joints, the hysteresis loop is first determined, and then the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted. The results were verified against available experimental data from other literature, and a good agreement was observed between the FEM results and experimental data. The results showed that the joint’s tensile strength without a probe hole (refilled hole) is higher than the joint with a probe hole. Therefore, re-filling the probe hole is an effective method for structures jointed by FSSW subjected to a static load. The fatigue strength of the joint with a re-filled probe hole was nearly the same as the structure with a probe hole at low applied loads. Additionally, at a high applied load, the fatigue strength of joints with a refilled probe hole was slightly lower than the joint with a probe hole.

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.

Effect of electroplating and nonmetallic coatings on fatigue strength of martensitic stainless steels

1974 ◽  
Vol 8 (4) ◽  
pp. 395-397
Author(s):  
T. N. Kalichak ◽  
V. I. Pokhmurskii ◽  
Ya. L. Poberezhnyi ◽  
M. F. Alekseenko ◽  
N. N. Mel'nikova
Keyword(s):  
Fatigue Strength ◽  
Stainless Steels ◽  
Martensitic Stainless Steels

Effect of Processing Layer on Fatigue Strength of Extruded AZ61 Magnesium Alloy

2013 ◽  
Vol 577-578 ◽  
pp. 429-432 ◽  
Author(s):  
Yukio Miyashita ◽  
Kyohei Kushihata ◽  
Toshifumi Kakiuchi ◽  
Mitsuhiro Kiyohara
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Magnesium Alloy ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Initiation ◽  
Fatigue Tests ◽  
Crack Growth Resistance ◽  
Az61 Magnesium Alloy

Fatigue Property of an Extruded AZ61 Magnesium Alloy with the Processing Layer Introduced by Machining was Investigated. Rotating Bending Fatigue Tests were Carried out with the Specimen with and without the Processing Layer. According to Results of the Fatigue Tests, Fatigue Life Significantly Increased by Introducing the Processing Layer to the Specimen Surface. Fatigue Crack Initiation and Propagation Behaviors were Observed by Replication Technique during the Fatigue Test. Fatigue Crack Initiation Life of the Specimen with the Processing Layer was Slightly Longer than that of the Specimen without the Processing Layer. Higher Fatigue Crack Growth Resistance was also Observed when the Fatigue Crack was Growing in the Processing Layer in the Specimen with the Processing Layer. the Longer Fatigue Life Observed in the Fatigue Test in the Specimen with the Processing Layer could be Mainly due to the Higher Crack Growth Resistance. it is Speculated that the Fatigue Strength can be Controlled by Change in Condition of Machining Process. it could be Effective way in Industry to Improved Fatigue Strength only by the Cutting Process without Additional Surface Treatment Process.

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