scholarly journals Fatigue Strength Evaluation for Remanufacturing Impeller of Centrifugal Compressor Based on Modified Grey Relational Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Qingchao Sun ◽  
Bowen Shi ◽  
Xiaokai Mu ◽  
Kepeng Sun
Keyword(s):  
Experimental Data ◽  
Fatigue Strength ◽  
Transformation Method ◽  
Relational Theory ◽  
Relational Model ◽  
Target Strength ◽  
Correction Function ◽  
Strength Data ◽  
Grey Relational ◽  
Target Data

The fatigue strength, as the essential basis of residual life evaluation, is required to be obtained timely for remanufacturing. Since impeller damage is characterized with very-high-cycle fatigue (VHCF), it is difficult to directly test the strength data. The transformation method of multisource strength data is proposed to predict fatigue strength for impeller based on grey relational theory. The multisource strength data, as factor space, primarily include available existing experimental data and operating data, while the strength data of the remanufacturing impeller are taken as target data. The fatigue strength model of material and component are presented to analyze the influence factors of remanufacturing target strength. And similar material provides a theoretical basis for selecting reference data reasonably. Considering the correlation and difference between available data and target data, the grey relational function is established, and the correction function of the target residual is brought forward to reduce the transformation deviation. The entropy-weight theory is implemented to determine the different impacts of multisource data on target strength. A test case, predicting the unknown impeller fatigue strength with various impellers, is applied to validate the proposed transformation method, and the results show that the predicted strength data are consistent with the experimental data well.

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.

Surface Image Edge Detection Algorithm Based on Grey Relational Analysis

2012 ◽  
Vol 461 ◽  
pp. 343-346 ◽  
Author(s):  
Gang Li ◽  
Ying Fang ◽  
Ya La Tong
Keyword(s):  
Edge Detection ◽  
Good Method ◽  
Detection Algorithm ◽  
Relational Model ◽  
Small Data ◽  
The Road ◽  
Image Edge Detection ◽  
Surface Image ◽  
Image Edge ◽  
Grey Relational

Automatic detection of pavement cracks is one of the very hot topics. For the characteristics of “small data, poor information” in the surface image processing, we construct ed a grey image relational model to characterize the local image edge feature, by selecting the appropriate threshold to extract the edge of appropriate level. Finally, simulation experiments show that the new algorithm can effectively improve the road edge detection results, and it is an effective good method worthy further study.

Fatigue Bending Strength of Jones Fracture Specific Screw Fixation

2017 ◽  
Vol 39 (4) ◽  
pp. 493-499 ◽  
Author(s):  
James Jastifer ◽  
Kirk A. McCullough
Keyword(s):  
Fatigue Strength ◽  
Bending Strength ◽  
Fatigue Testing ◽  
Screw Fixation ◽  
Optimal Choice ◽  
Fatigue Properties ◽  
Strength Data ◽  
Screw Design ◽  
Jones Fracture ◽  
Significant Difference

Background: Intramedullary screw fixation is a common method of treating proximal metadiaphyseal fifth metatarsal (ie, Jones) fractures. Fatigue failure is a complication of this fixation. There are many screw designs available, including Jones fracture specific fixation, but the optimal choice of screw design is unknown. The purpose of this study was to compare the fatigue strength of Jones fracture specific screw designs as well as other commonly used screw designs. Our hypothesis was that there would be no difference in fatigue strength for Jones fracture specific screw designs at similar screw diameters. Methods: A study was performed to determine the fatigue bending strength of 5 different screw designs including Jones fracture specific screw designs at 3 different screw diameters. Six screws of each size and design underwent cyclic fatigue testing, and a median fatigue limit (MFL) was determined for each screw design and size. Results: The Stryker Asnis JFX solid 4.0-mm, 5.0-mm, and 6.0-mm screws had a higher MFL than all other screws with similar diameter tested (all P < .0001). Both Jones fracture specific screw designs (Stryker Asnis JFX solid screws and Charlotte Carolina Jones screws) had higher MFLs than the other screw designs tested. Conclusion: This study provides comparative fatigue strength data on larger screw diameters, which have not been previously reported. There was a statistically significant difference in screw fatigue properties at the screw diameters tested. Clinical Relevance: The clinical significance of this study is that it provides surgeons with fatigue strength data to aid in screw selection for Jones fracture fixation.

Grey Correlation Model Based on Diatom Indices Evaluating Water Quality of Longjiang River

2013 ◽  
Vol 448-453 ◽  
pp. 43-47 ◽  
Author(s):  
Xin Tang ◽  
De Suo Cai ◽  
Wen Ting Yao
Keyword(s):  
Water Quality ◽  
Water Quality Assessment ◽  
Quality Standard ◽  
Relational Model ◽  
Water Quality Standard ◽  
Diatom Index ◽  
Model Based ◽  
Diatom Indices ◽  
Grey Relational

In order to evaluate the water quality of Longjiang river comprehensively, diatoms of 15 sampling sites are collected to establish the Grey Relational Model based on three diatom indexesIPS, IBD and IDG. From the Cluster analysis of sampling sites and the box plot of diatom index, IBD is the best, then the IPS, the diatom index weights on water quality assessment are 0.637 for IBD, 0.2583 for IPS, 0.1074 for IDG respectively. Finally, by comparing the water quality standard level based on Grey Relational Model, it can be known that the water quality of most sampling sites is fine except that site No.1 and No.3 belong to III water quality standard. The result shows that it is more comprehensive and reasonable to use the Grey Relational Model based on diatom index rather than individual diatom index to assess water quality.

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