scholarly journals Experimental and finite element analysis of the influence of contact pressure on fretting fatigue behavior of Al-Zn-Mg alloy

2020 ◽  
Vol 57 (02) ◽  
pp. 143-149
Author(s):  
Jiang Xiaosong ◽  
Li Jingrui ◽  
Liu Wanxia ◽  
Zhu Degui
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Fatigue Behavior ◽  
Fretting Fatigue ◽  
Mg Alloy ◽  
Element Analysis

scholarly journals Effect of coronal plane acetabular correction on joint contact pressure in Periacetabular osteotomy: a finite-element analysis

2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Kenji Kitamura ◽  
Masanori Fujii ◽  
Miho Iwamoto ◽  
Satoshi Ikemura ◽  
Satoshi Hamai ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Periacetabular Osteotomy ◽  
Anterior Wall ◽  
Coronal Plane ◽  
Patient Specific ◽  
Element Analysis ◽  
Joint Contact ◽  
Joint Contact Pressure

Abstract Background The ideal acetabular position for optimizing hip joint biomechanics in periacetabular osteotomy (PAO) remains unclear. We aimed to determine the relationship between acetabular correction in the coronal plane and joint contact pressure (CP) and identify morphological factors associated with residual abnormal CP after correction. Methods Using CT images from 44 patients with hip dysplasia, we performed three patterns of virtual PAOs on patient-specific 3D hip models; the acetabulum was rotated laterally to the lateral center-edge angles (LCEA) of 30°, 35°, and 40°. Finite-element analysis was used to calculate the CP of the acetabular cartilage during a single-leg stance. Results Coronal correction to the LCEA of 30° decreased the median maximum CP 0.5-fold compared to preoperatively (p <  0.001). Additional correction to the LCEA of 40° further decreased CP in 15 hips (34%) but conversely increased CP in 29 hips (66%). The increase in CP was associated with greater preoperative extrusion index (p = 0.030) and roundness index (p = 0.038). Overall, virtual PAO failed to normalize CP in 11 hips (25%), and a small anterior wall index (p = 0.049) and a large roundness index (p = 0.003) were associated with residual abnormal CP. Conclusions The degree of acetabular correction in the coronal plane where CP is minimized varied among patients. Coronal plane correction alone failed to normalize CP in 25% of patients in this study. In patients with an anterior acetabular deficiency (anterior wall index < 0.21) and an aspherical femoral head (roundness index > 53.2%), coronal plane correction alone may not normalize CP. Further studies are needed to clarify the effectiveness of multiplanar correction, including in the sagittal and axial planes, in optimizing the hip joint’s contact mechanics.

Evaluation of the Elliptical Flange Configurations for 24-Inch and 30-Inch Heater/Cooler Units

2007 ◽  
Author(s):  
Chris Alexander ◽  
Wade Armer ◽  
Stuart Harbert
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Exchanger ◽  
Contact Pressure ◽  
Parameter Study ◽  
Element Analysis ◽  
Iterative Design ◽  
Pressure Changes ◽  
Geometric Changes ◽  
Maximum Contact

KOCH Heat Transfer Company contracted Stress Engineering Services, Inc. to perform a design/parameter study of a return bonnet used in hairpin heat exchangers that employs an elliptical flange design. The return bonnet is an important component of the heat exchanger as it can be removed to permit inspection of the heat exchanger tubes. The return bonnet is bolted to the hairpin leg flange. To maintain sealing integrity a gasket is placed between the return bonnet flange and the hairpin leg flange. The sealing efficiency of two return bonnet sizes (24-inch and 30-inch) was investigated in this study using finite element analysis. The sealing efficiency is an indication of how the contact pressure changes circumferentially around the gasket and is calculated by dividing the local contact pressure by the maximum contact pressure calculated in the gasket for each respective design. The study assessed the effects of geometric changes to the mating flanges. Using an iterative design process using finite element analysis, the elliptical flanges were optimized to maximize sealing efficiency. Upon completion of the study, the manufacturer successfully employed the modifications as evidenced with multiple successful hydrotests.

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