scholarly journals Assessment of the Impact of Shot-Peening on the Fatigue Life of a Compressor Blade Subjected to Resonance Vibrations

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5726
Author(s):  
Arkadiusz Bednarz ◽  
Wojciech Z. Misiolek
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Geometric Model ◽  
Fatigue Analysis ◽  
Compressor Blade ◽  
Strength Analysis ◽  
Equivalent Stresses ◽  
Resonance Vibrations ◽  
Secondary Objective ◽  
The Impact

This publication presents an assessment of the influence of a surface treatment such as shot-peening on the fatigue life of a compressor blade exposed to resonant vibrations. As part of the work, a geometric model of the blade was developed, and a numerical modal and fatigue analysis were performed. The fatigue analysis was based on the Manson–Coffin–Basquin and Ramberg–Osgood models. Additionally, the location of the highest equivalent stresses was established. Based on the results of the strength analysis, two points were identified where a fatigue crack may potentially occur. As part of the work, the influence of different values of residual stresses on the results of the fatigue life was determined. The obtained results were compared to the literature values of fatigue life for this blade. A secondary objective of the study was to determine the size of the grains at various points of the blade, as well as the thickness of the layer plasticized as a result of peening. The relationship between the location of the highest values of the equivalent stresses and the thickness of the plasticized layer was determined. An explanation of the effect of shot-peening on the increase in the fatigue life of the blade was proposed.

scholarly journals Assessment of the Impact of Shot Peening on the Fatigue Life of a Compressor Blade Subjected to Resonance Vibrations

2020 ◽  
Author(s):  
Arkadiusz Bednarz ◽  
Wojciech Misiołek
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Geometric Model ◽  
Fatigue Analysis ◽  
Compressor Blade ◽  
Resonant Vibrations ◽  
Equivalent Stresses ◽  
Resonance Vibrations ◽  
The Impact ◽  
The Relationship

The publication presents the assessment of the influence of surface treatment such as shot-peening on the fatigue life of a compressor blade exposed to resonant vibrations. As part of the work, a geometric model of the blade was developed and a numerical modal and fatigue analysis were performed. The fatigue analysis was based on the Manson-Coffin-Basquin and Ramberg-Osgood models. As part of the work, the influence of different values of residual stresses on the results of fatigue life was determined. Additionally, the location of the highest equivalent stresses was established. The obtained results of the numerical analyzes were compared with the results presented in the scientific literature. An additional aim of the study was to determine the size of the grains at various points of the blade as well as the thickness of the layer plasticized as a result of peening. The obtained results are presented in the form of tables and charts. The relationship between the location of the highest values of equivalent stresses and the thickness of the plasticized layer was determined. The explanation of the effect of shot peening on the increase in fatigue life of the blade was proposed.

scholarly journals Experimental Investigation on the Effect of Shot Peening and Deep Rolling on the Fatigue Response of High Strength Fasteners

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1093 ◽  
Author(s):  
Reggiani
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
High Strength Steels ◽  
High Strength ◽  
Experimental Tests ◽  
Published Data ◽  
Deep Rolling ◽  
Beneficial Impact ◽  
The Impact ◽  
Fatigue Life Enhancement

Shot-peening and deep rolling are mechanical surface treatments that are commonly applied to enhance the fatigue performances of components, owing to their capacity to generate compressive residual stresses and induce work hardening. However, literature is still poor of published data concerning the application of these treatments to high strength steels fasteners, although these represent a class of components among the most widespread. In the present work, the impact of deep rolling and shot-peening performed in the underhead radius of two set of fasteners made of 36NiCrMo and 42CrMoV for fatigue life enhancement has been investigated. The experimental tests consisted of six combinations of shot-peening and deep rolling, including the non-treated state. Two test campaigns have been sequentially carried out with different process parameters and treatment sequences. The results always showed a beneficial impact of the deep rolling on fatigue, especially for the 42CrMoV steel. Conversely, the effect of the shot-peening strongly depended on the selected set of parameters, alternatively leading to an improvement or a worsening of the fatigue life in relation to the level of induced surface roughness.

Effects of Surface Treatments on the Fatigue Response of High Strength Fasteners

2019 ◽  
Vol 813 ◽  
pp. 352-357 ◽  
Author(s):  
Barbara Reggiani ◽  
Giorgio Olmi ◽  
Leonardo Orazi ◽  
Luca Tomesani ◽  
Stefano Fini ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Rolling Force ◽  
High Strength ◽  
Deep Rolling ◽  
Experimental Campaign ◽  
Life Enhancement ◽  
The Impact ◽  
Fatigue Life Enhancement ◽  
Treated State

The aim of the present work was the assessment of the impact of deep-rolling and shot-peening performed in the underhead and in the unthreaded shank of two high strength screws (36 NiCrMo and 42 CrMoV) for fatigue life enhancement. The experimental campaign consisted of six combinations, including the non-treated state. The aforementioned treatments were evaluated alone or with shot-peening performed after deep-rolling in the underhead fillet of the screws. Deep rolling was carried out at the optimal rolling force, whereas two shot diameters were considered for shot-peening (Z100 and UFS70). The results have been evaluated in terms of fatigue limits and factor effects have been assessed by marginal mean plots.

scholarly journals Design and Fatigue Analysis of Shot Peened Leaf Spring

2019 ◽  
Vol 9 (1) ◽  
pp. 1120-1126
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
High Strength ◽  
Load Level ◽  
Spring Steel ◽  
Leaf Spring ◽  
Leaf Springs ◽  
Point Test ◽  
Life Improvement ◽  
The Impact

The paper handles the fatigue and failing analysis of serial shot-peened leaf springs of cumbersome vehicles emphasizing on the impact of shot peening on fatigue life, coping with automotive leaf springs, the shot peening method turns into an important step in production.In the situation of leaf spring suspensions, however, asystematic research of the effect of shot peening about fatigue life isstill required. Experimental stress-life curves are determined with the aid of the usage of investigating clean specimen subjected to shot peening. those test consequences are as compared to corresponding ones identified from cyclic three-point test on shot peened serial leaf springs in order to show the influence of applied heat treatment and shot peening approach on fatigue existence of high-strength used to get leaf spring manufacturing, reliant on the load level. Analyses are performed to explain the effects resulting from shot peening practice on the surface features of the high-strength spring steel under examination. The evaluation of fatigue results shows that almost no life improvement due to production highlighting the importance for mutual variation in parameters of shot peening and thermal treatment so that there is sufficient progress in life

Fatigue Analysis at the Tower of a 12MW Floating Offshore Wind Turbine

2018 ◽  
Author(s):  
Junbae Kim ◽  
Hyeonjeong Ahn ◽  
Byoungcheon Seo ◽  
Hyunkyoung Shin
Keyword(s):  
Fatigue Life ◽  
Wind Turbine ◽  
Fatigue Analysis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Strength Analysis ◽  
Cycle Number ◽  
Floating Offshore Wind Turbine ◽  
Design Life ◽  
Safety Margins

The initial design of a 12-MW floating offshore wind turbine (FOWT) was made by the University of Ulsan (UOU) based on the 5-MW offshore wind turbine of the National Renewable Energy Laboratory (NREL) using the law of similarity. The tower design was checked through the eigenfrequency and fatigue strength analysis according to the GL guideline of tower design conditions. The direct expansion of the 5 MW wind turbine support structure caused a resonance problem of the tower of the 12-MW UOU FOWT and the tower length was adjusted to avoid the 3P resonance. Wind turbines are required to have a design life of more than 20 years and shall be designed to endure both ultimate and fatigue loads experienced during the design life. The platform pitch motion of FOWTs due to combined wave and wind loading may result severely in both fore-aft forces and moments at the base of the tower. In this study, we used the simplified fatigue analysis, which is generally applied when considering safety margins by stress to predict the fatigue life of tower. In order to calculate the fatigue load, the Markov matrix was constructed by using the cycle counting method to determine range, average value, and cycle number of loads from peak and valley values of actual load histories simulated by FAST v8 of the tower base. The predicted fatigue life at the tower base was follow by S/N curves for welded steel structures and it was calculated by the Palmgren-Miner’s rule.

Comparative Study on Fatigue Life of Drillship Operating for GoM and Brazil Sectors Based on Spectral Fatigue Analysis

2013 ◽  
Author(s):  
Tae-Hoon Kim ◽  
Oe-Ju Hwang ◽  
Yeong-Tae Oh
Keyword(s):  
Fatigue Life ◽  
Comparative Study ◽  
Fatigue Analysis ◽  
Strength Analysis ◽  
Local Strength ◽  
Analysis System ◽  
The Comparative Study ◽  
In Transit ◽  
Fatigue Endurance ◽  
Moon Pool

A drillship is an exceptional vessel to be capable of drilling of new oil or gas wells, and carrying out maintenance or completion work in deep water. The drillship also has ability to take aboard much more variable loads and save the time of sailing between oil fields worldwide than Semi-submersible rig. Sometimes, it is required from design specifications that a drillship is to be designed to be satisfactory to several fields at the same time to maximize such advantages. This paper describes results of the comparative study on fatigue life of a drillship, which was developed by DSME, operating for both GoM (Gulf of Mexico) and Brazil sectors. It was assumed in the calculation that the drillship spends 80% of her life in On-site (GoM and/or Brazil sector) and other percentage in transit condition. Screening works for choosing fatigue sensitive locations such as moon pool corners, discontinuous areas, topside module foundations, etc., were performed referring to the local strength analysis. A whole ship model along with every topside module was generated and the very fine meshes with thickness by thickness as per DNV RP-C203 were embedded therein. Stress RAOs of critical hotspot locations of the drillship were directly obtained through its motions from 3D potential-theory-based analysis, i.e. DNV WADAM. In the analysis, wave scatter diagrams given by BMT were used. As results of the study, it was found that Brazil sector gives comparatively worse results to the drillship in terms of fatigue endurance and finally, Brazil sector was decided in calculating fatigue lives of the drillship as a representative sea state. The fatigue life was computated based on spectral fatigue analysis by means of DSME’s in-hose tool (i.e. D-SFAS, DSME Spectral Fatigue Analysis System).

Performance-Based Geometric Tolerancing of Compressor Blades

2004 ◽  
Author(s):  
Caroline Twomey Lamb ◽  
David L. Darmofal
Keyword(s):  
Geometric Model ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Compressor Blade ◽  
Geometric Parameters ◽  
Performance Limits ◽  
Compressor Blades ◽  
Performance Limit ◽  
Geometric Tolerancing ◽  
The Impact

The relationship between statically measured geometric parameters (tolerances) and the aerodynamic performance of an airfoil are investigated in this paper. The goal is to determine which geometric parameters are critical to control during manufacturing, such that a blade will have acceptable aerodynamic performance. A probabilistic model of geometric variability for a three-dimensional blade is derived. Using this geometric model, probabilistic aerodynamic simulations are conducted to analyze the variability in aerodynamic performance. Tolerance optimization is then applied in which tolerance ranges are modified to best sort blades according to some arbitrary performance limit. The optimization is performed for several limits, expressed as a percent of nominal performance, to observe both which parameters best predict performance and the accuracy of that prediction at each limit. Two blade cases are considered, both based on the same compressor blade: the base compressor blade with nominal manufacturing noise; and a probabilistic redesign of the blade geometry designed to minimize the impact of manufacturing noise, also analyzed with nominal manufacturing noise. Results show the best static indicators of meanline performance are parameters concerning the LE of the airfoil, and the effectiveness of these parameters vary greatly depending on the chosen performance limit. In addition, it was shown that the optimized tolerances for the redesigned blade were consistently looser, or less restrictive, than those for the original blade population for a given performance limit. The differences in observed optimized tolerance ranges are small for less restrictive performance limits but at more aggressive performance limits, there is a 20–30% increase in tolerance range for the redesigned blade population.

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

scholarly journals The impact of COVID-19 on antipsychotic prescriptions for patients with schizophrenia in Australia

2021 ◽  
pp. 000486742110257
Author(s):  
Steve Kisely ◽  
Dante Dangelo-Kemp ◽  
Mark Taylor ◽  
Dennis Liu ◽  
Simon Graham ◽  
...  
Keyword(s):  
Human Services ◽  
Primary Outcome ◽  
Medical Consultation ◽  
Australian Government ◽  
Provider Type ◽  
Study Population ◽  
Secondary Objective ◽  
Long Acting ◽  
The Impact ◽  
Pharmaceutical Benefits Scheme

Objective: To assess the impact, in the Australian setting, of the COVID-19 lockdown on antipsychotic supplies for patients with schizophrenia following a prescription from a new medical consultation when compared to the same periods in the previous 4 years. A secondary objective was to assess the volume of all antipsychotic supplies, from new and repeat prescriptions, over these same periods. Methods: A retrospective pharmaceutical claims database study was undertaken, using the Department of Human Services Pharmaceutical Benefits Scheme 10% sample. The study population included all adult patients with three or more supplies of oral or long-acting injectable antipsychotics for the treatment of schizophrenia at any time between 1 June 2015 and 31 May 2020. The primary outcome compared volumes of dispensed antipsychotics from new prescriptions (which require a medical consultation) between 1 April and 31 May each year from 2016 to 2020. This was to analyse the period during which the Australian Government imposed a lockdown due to COVID-19 (April to May 2020) when compared the same periods in previous years. Results: There was a small (5.7%) reduction in the number of antipsychotics dispensed from new prescriptions requiring a consultation, from 15,244 to 14,372, between April and May 2019 and the same period in 2020, respectively. However, this reduction was not statistically significant ( p = 0.75) after adjusting for treatment class, age, gender, location and provider type. Conclusion: The COVID-19 restrictions during April and May 2020 had no significant impact on the volume of antipsychotics dispensed from new prescriptions for patients with schizophrenia when compared to the volume of antipsychotics dispensed from new prescriptions during the same period in previous years.

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