scholarly journals Estimation of Facial Contact Pressure Based on Finite Element Analysis

2019 ◽  
pp. 657-667
Author(s):  
Wonsup Lee ◽  
Jin-Gyun Kim ◽  
Johan M. F. Molenbroek ◽  
Richard H. M. Goossens ◽  
Heecheon You
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
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.

THE EFFECT OF ASPHERICITY OF ACETABULAR BEARING SURFACE ON CONTACT MECHANICS OF UHMWPE TOTAL HIP IMPLANTS BY FINITE ELEMENT ANALYSIS

2017 ◽  
Vol 17 (01) ◽  
pp. 1750011 ◽  
Author(s):  
XUAN ZHANG ◽  
LING WANG ◽  
XIFENG PENG ◽  
DICHEN LI ◽  
JIANKANG HE ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Mechanics ◽  
Contact Pressure ◽  
Surface Profile ◽  
Surface Measurement ◽  
Element Analysis ◽  
Actual Surface ◽  
Total Hip ◽  
Measuring Machine

Asphericity and out-of-roundness are generally used to evaluate the manufacturing quality of ultra-high molecular weight polyethylene (UHMWPE) cup inner surfaces, which can potentially affect initial clinical wear and contribute to osteolysis of total hip arthroplasty. This study measured the location and magnitude of asphericity and the out-of-roundness value for four UHMWPE cups in a single set, and then investigated the effects of the asphericity on the contact mechanics of UHMWPE cups. A co-ordinate measuring machine (CMM) was used for the surface measurement and finite element analysis (FEA) was adopted for contact mechanics study. The results demonstrated that the asphericity varied between cups with the maximum value as 0.088[Formula: see text][Formula: see text][Formula: see text]0.004[Formula: see text]mm. Although such a value met the ISO specification, large difference of volume appeared for the asphericity above 0.060[Formula: see text]mm. Actual surface profile accounting for the asphericity was found to affect the value of contact pressure and contact area by around 12%. The inferior asphericity resulted in a nonsmoothly distributed contact pressure, which had a negative effect on the contact mechanics of UHMWPE cups and the edge loading was predicted to occur for the sample with a large asphericity. In conclusion, the asphericity of UHMWPE cup could affect the contact mechanics of the articular bearings and may subsequently contribute to initial wear during bedding-in phase.

Analysis of Contact Pressure Distribution on 3-Bolt Self-Energized Connector Seals

2009 ◽  
Author(s):  
Rajeev Madazhy ◽  
Sheril Mathews ◽  
Erik Howard
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Distribution ◽  
Contact Pressure ◽  
Maximum Pressure ◽  
Operating Pressure ◽  
Seal Ring ◽  
Contact Pressure Distribution ◽  
Element Analysis ◽  
Novel Design

A novel design using 3 bolts for a self-energized seal connector is proposed for quick assembly applications. Contact pressure distribution on the surface of the seal ring during initial bolt-up and subsequent operating pressure is analyzed for 3″ and 10″ connectors using Finite Element Analysis. FEA is performed on a 3″ and 10″ ANSI RF flange assembly and contact pressure distribution on the RF gasket is compared with the tapered seal ring assemblies. Hydrostatic tests are carried out for the tapered seal and ANSI bolted connectors to evaluate maximum pressure at which leak occurs for both size assemblies.

scholarly journals Effect of cartilage thickness mismatch in osteochondral grafting from knee to talus on articular contact pressures: A finite element analysis

2021 ◽  
Vol 32 (2) ◽  
pp. 355-362
Author(s):  
Ömer Faruk Kılıçaslan ◽  
Ali Levent ◽  
Hüseyin Kürşat Çelik ◽  
Mehmet Ali Tokgöz ◽  
Özkan Köse ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Equivalent Stress ◽  
Cartilage Thickness ◽  
Frictional Stress ◽  
Element Analysis ◽  
Grafting From ◽  
Von Mises ◽  
Osteochondral Grafting

Objectives: The aim of this study was to investigate the effect of cartilage thickness mismatch on tibiotalar articular contact pressure in osteochondral grafting from femoral condyles to medial talar dome using a finite element analysis (FEA). Materials and methods: Flush-implanted osteochondral grafting was performed on the talar centromedial aspect of the dome using osteochondral plugs with two different cartilage thicknesses. One of the plugs had an equal cartilage thickness with the recipient talar cartilage and the second plug had a thicker cartilage representing a plug harvested from the knee. The ankle joint was loaded during a single-leg stance phase of gait. Tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values), and deformation were analyzed. Results: In both osteochondral grafting simulations, tibiotalar contact pressure, frictional stress, equivalent stress (von Mises values) on both tibial and talar cartilage surfaces were restored to near-normal values. Conclusion: Cartilage thickness mismatch does not significantly change the tibiotalar contact biomechanics, when the graft is inserted flush with the talar cartilage surface.

THEORETICAL AND FINITE ELEMENT ANALYSIS TO DETERMINE CONTACT PRESSURE, VONMISSES STRESSES AND WEAR IN CAM AND FOLLOWER FOR VARIOUS CAM ROTATIONAL ANGLES IN IC ENGINE

2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Jayakumar K ◽  
Aldrin Raj J ◽  
Somesh Subramanian S
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Contact Pressure ◽  
Compressive Force ◽  
Surface Wear ◽  
Hertz Contact ◽  
Element Analysis ◽  
Ic Engine ◽  
Rotational Angle ◽  
Base Circle

The contact between the cam and follower that exists in the valve strain system of IC engine influences wear. The dynamic analysis of cam and follower system in carried to find the normal compressive force for various cam rotational angles. Based on this compressive force on the cam, the hertz contact stresses and surface wear are calculated theoretically. Finite element analysis was carried out in the three critical portions of the cam such as cam nose region, cam tangent region and cam base circle region to compare the results. The results showed that cam rotational angle directly affects the contact pressure. The max contact pressure occurs in the nose end of the cam. The results showed that principle stress and wear also increases with cam rotational angle

Sign in / Sign up

Export Citation Format

Share Document