Research on the Very-High-Cycle Fatigue Life Analysis of High-Speed Take-Up Winder

2014 ◽  
Vol 488-489 ◽  
pp. 1281-1284
Author(s):  
Yong Li ◽  
Wen Qin Liu ◽  
Zhou Yang
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
High Speed ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Chemical Fiber ◽  
Cycle Fatigue ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Vibration Performance

The take-up winder is an important equipment of chemical fiber textile machinery. Vibration performance is the key to decide quality and service life of product. The modal of winder is analyzed. It is shown that the rotation speed cannot be kept away from fifth and sixth resonance frequency. The Maximum stress response is calculated by harmonic analysis. According to results of high-cycle fatigue tests, the service life of winder is evaluated. The results show that there is the risk of fatigue damage for small damp ratio. Unlimited fatigue life can be obtained by creasing damp ratio. It can be concluded that creasing damp is an effective way to improve the service life.

High-cycle fatigue tests of pretensioned concrete beams

PCI Journal ◽  
2022 ◽  
Vol 67 (1) ◽  
Author(s):  
Jörn Remitz ◽  
Martin Empelmann
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Concrete Beams ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Design Methods ◽  
Test Results ◽  
Cycle Fatigue ◽  
Pretensioned Concrete ◽  
Current Design

Pretensioned concrete beams are widely used as bridge girders for simply supported bridges. Understanding the fatigue behavior of such beams is very important for design and construction to prevent fatigue failure. The fatigue behavior of pretensioned concrete beams is mainly influenced by the fatigue of the prestressing strands. The evaluation of previous test results from the literature indicated a reduced fatigue life in the long-life region compared with current design methods and specifications. Therefore, nine additional high-cycle fatigue tests were conducted on pretensioned concrete beams with strand stress ranges of about 100 MPa (14.5 ksi). The test results confirmed that current design methods and specifications overestimate the fatigue life of embedded strands in pretensioned concrete beams.

High Cycle Fatigue Behavior of Recycled Additive Manufactured Electron Beam Melted Titanium Ti6Al4V

2020 ◽  
Author(s):  
Melody Mojib ◽  
Rishi Pahuja ◽  
M. Ramulu ◽  
Dwayne Arola
Keyword(s):  
Electron Beam ◽  
Fatigue Life ◽  
Rough Surface ◽  
High Cycle Fatigue ◽  
Fatigue Behavior ◽  
High Strength ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Initiation And Propagation ◽  
Powder Recycling

Abstract Metal Additive Manufacturing (AM) has become a popular method for producing complex and unique geometries, especially gaining traction in the aerospace and medical industries. With the increase in adoption of AM and the high cost of powder, it is critical to understand the effects of powder recycling on part performance to move towards material qualification and certification of affordable printed components. Due to the limitations of the Electron Beam Melting (EBM) process, current as-printed components are susceptible to failure at limits far below wrought metals and further understanding of the material properties and fatigue life is required. In this study, a high strength Titanium alloy, Ti-6Al-4V, is recycled over time and used to print fatigue specimens using the EBM process. Uniaxial High Cycle Fatigue tests have been performed on as-printed and polished cylindrical specimens and the locations of crack initiation and propagation have been determined through the use of a scanning electron microscope. This investigation has shown that the rough surface exterior is far more detrimental to performance life than the powder degradation occurring due to powder reuse. In addition, the effects of the rough surface exterior as a stress concentration is evaluated using the Arola-Ramulu. The following is a preliminary study of the effects powder recycling and surface treatments on EBM Ti-6Al4V fatigue life.

Novel Methods for High-Cycle Fatigue Life Determination

2019 ◽  
Vol 810 ◽  
pp. 40-45
Author(s):  
Pavel Konopík ◽  
Radek Procházka ◽  
Martin Rund ◽  
Jan Džugan
Keyword(s):  
Fatigue Life ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Testing Methods ◽  
Destructive Testing ◽  
New Approach ◽  
Constant Loading ◽  
Thermographic Analysis ◽  
Novel Methods

In the present paper, two novel methods for determining the fatigue limit are presented. Despite the fact that these methods are different in principle, both represent a new approach to testing where the main benefit is reduced consumption of material. The first method is based on small round specimens and can be considered as one of semi-destructive testing methods. The second method is based on infrared thermographic analysis and requires only one specimen. Results obtained with these techniques were compared with those obtained from standard high-cycle force-controlled fatigue tests under constant loading until failure.

Prediction of Low-Cycle Fatigue Life of Specimens With Fabrication Flaws

1968 ◽  
Vol 90 (4) ◽  
pp. 620-626 ◽  
Author(s):  
A. G. Pickett
Keyword(s):  
Fatigue Life ◽  
Crack Initiation ◽  
Low Cycle Fatigue ◽  
Small Specimen ◽  
Cycle Fatigue ◽  
Notch Stress ◽  
Weld Defect ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Crack Initiation Life

A modification of the notch stress procedure for fatigue-life analysis is presented. The importance of considering the mechanics of the specimen and the effects of the notch on specimen mechanics is illustrated by example. The procedure is applied to correlate the results of small specimen tests with large weld defect specimen tests. The significance of crack-initiation life and crack-propagation life and the dependence of these portions of total fatigue life on specimen geometry and loading is developed.

High-Cycle Fatigue Life of AZ31 and AZ61 Magnesium Alloys

2013 ◽  
Vol 211 ◽  
pp. 83-88
Author(s):  
Marek Cieśla
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Magnesium Alloys ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Test Material ◽  
Cycle Fatigue ◽  
Structural Components ◽  
Asymmetry Coefficient ◽  
Fatigue Fractography

Usefulness of the magnesium alloys for construction of structural components is determined, apart from their low density, by a number of favourable mechanical properties and in the case of their use for components of transport means additionally by good fatigue strength. In this study, 12 mm diameter extruded rods of AZ31 and AZ61 magnesium alloys were used as test material. After extrusion the rods were annealed at a temperature of 400°C, with a 60 min soaking period and subsequent cooling in air. Cylindrical specimens with a diameter of d0 = 8 mm were made for the fatigue test under high-cycle rotary bending conditions with the cycle asymmetry coefficient R = -1. The tests were carried out for a limited fatigue strength range. Examination of microstructure of tested alloys and fatigue fractography were also performed. During the high-cycle fatigue tests it was found that the AZ61 alloy has a longer fatigue life. Based on the obtained results, fatigue life characteristics of the tested materials were drawn up.

A Methodology for Predicting the Variance of Fatigue Life Incorporating the Effects of Manufacturing Processes

2002 ◽  
Vol 124 (3) ◽  
pp. 745-753 ◽  
Author(s):  
Xiaoping Yang ◽  
C. Richard Liu
Keyword(s):  
Fatigue Life ◽  
Variance Reduction ◽  
High Cycle Fatigue ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Reliability Design ◽  
Average Value ◽  
Individual Variables ◽  
Input Variables ◽  
Verification Model

It is well known that there is a large variance of fatigue life associated with the data of fatigue tests under nominally identical conditions. Understanding and controlling this variance are essential to enhance the safety and competitiveness of designing and manufacturing fatigue critical products. However, no analytical model quantitatively linking input variables with the variance of fatigue life has been found in current literature. To address this issue, a methodology for analytically predicting the variance of fatigue life is proposed. Using this methodology, the variance of fatigue life can be decomposed into individual components. The significance of this decomposition is two-fold. First, it provides a tool for pinpointing key driving factors of the variance of fatigue life, which is essential for the variance reduction of fatigue life. Second, the time consuming and costly fatigue tests to obtain critical variance information for reliability design may be divided into less time consuming tests for obtaining variance information for individual variables contributing to fatigue variance. Based on the variance prediction tool, a methodology for systematically incorporating manufacturing influence into the prediction of variance and average value of fatigue life is proposed. A verification model is built to predict the variance and average value of fatigue life of a structure with a central hole in the high cycle fatigue regime. The predicted fatigue life matches the actual average fatigue life well. Statistical analysis shows that the predicted variances of the fatigue life are equal to those estimated from actual fatigue life.

Fatigue Life Analysis of Steel Pipelines With Plain Dents Under Cyclic Internal Pressure

2008 ◽  
Author(s):  
Bianca de Carvalho Pinheiro ◽  
Ilson Paranhos Pasqualino ◽  
Se´rgio Barros da Cunha
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Internal Pressure ◽  
Fatigue Tests ◽  
Small Scale ◽  
Concentration Factors ◽  
Life Analysis ◽  
Fatigue Life Analysis ◽  
Stress Concentration Factors

This work is within an ongoing study, which aims to propose a new methodology for fatigue life analysis of steel pipelines with plain dents under cyclic internal pressure. This methodology follows the current high cycle fatigue theory and employs stress concentration factors induced by plain dents to modify standard S-N curves. A previously developed and validated finite element model is extended to generate stress concentration factors for longitudinal and transverse dents, in addition to spherical dents. Several finite element analyses are carried out in a parametric study to evaluate stress concentration factors induced by the three dent types studied: spherical, longitudinal and transverse dents. Analytical expressions are developed to estimate stress concentration factors for these three dent types as function of pipe and dent geometric parameters. Small-scale fatigue tests are conducted to evaluate the finite life behavior of dented steel pipes under cyclic internal pressure. The methodology is validated in view of the fatigue tests results. Including expressions to estimate stress concentration factors for three different dent types (spherical, longitudinal and transverse dents), the proposed methodology can then be used for fatigue life analysis of dented steel pipelines under cyclic internal pressure.

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