scholarly journals Experimental analysis of axial and radial stress distribution in soft materials used for petrochemical valve stem sealing package

2017 ◽  
Vol 174 ◽  
pp. 012004
Author(s):  
R G Ripeanu ◽  
A Ispas ◽  
D Ispas
Keyword(s):  
Stress Distribution ◽  
Experimental Analysis ◽  
Radial Stress ◽  
Soft Materials ◽  
Valve Stem ◽  
Materials Used

FE Modeling of Stress Distribution in MAO Coating on TC4 Substrate under Thermal Shock Cyclic Loading

2014 ◽  
Vol 941-944 ◽  
pp. 1629-1632 ◽  
Author(s):  
Ye Sheng Zhong ◽  
Li Ping Shi ◽  
Ming Wei Li ◽  
Jia Yu ◽  
Jian Han Liang ◽  
...  
Keyword(s):  
Shear Stress ◽  
Thermal Stress ◽  
Stress Distribution ◽  
Adhesive Strength ◽  
Thermal Cycle ◽  
Radial Stress ◽  
Numerical Study ◽  
Element Analysis ◽  
Solid Element ◽  
Cycle Loading

A numerical study using finite element analysis (FEA) was performed to investigate the thermal, shear and radial stresses developed in MAO coating on substrate of TC4 under thermal cycle loading. The four-node quadrilateral thermal solid element PLANE55 and four-node quadrilateral structural solid element PLANE42 with axisymmetric option was used to model the temperature distribution and thermal stress field of the MAO coating on TC4 substrates. The thermal stress, radial stress and shear stress along the thickness in film/substrate system are analyzed systematically under different thermal cycle loading. It is found that the thermal stress of MAO coating exhibits a linear relationship with thickness of substrate, but it exhibit a parabolic relationship with the thickness of the coating. The radial stress and shear stress distribution of the coating–substrate combination are also calculated. It is observed that high tensile shear stress of MAO coating on TC4 substrate reduces its adhesive strength but high-compressive shear stress improves its adhesive strength.

scholarly journals Alternative Use of Achi, UKPO, and OFOR as Substitute to Standard Viscosifier

2022 ◽  
Author(s):  
George Boyi ◽  
Godswill Amadi
Keyword(s):  
Experimental Investigation ◽  
Specific Gravity ◽  
Foreign Exchange ◽  
Experimental Analysis ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Gel Strength ◽  
Cost Cutting ◽  
Materials Used ◽  
Local Materials

In Nigeria, drilling companies import a bulk of drilling fluid materials that they use to carry out their respective operations. This has been a major concern to oil and gas industries since these drilling fluid materials cannot be recycled, are highly expensive in terms of foreign exchange, are not environmentally friendly, not very effective, and non-biodegradable. This work presents an experimental investigation into the reliability of the use of local materials as a substitute to conventional viscosifiers. Local materials used in the analysis are Mucuna solannie (Ukpo), Brachystegia eurycoma (Achi), and Detarium microcarpium (Ofo). The results obtained from the experimental analysis show that they compared closely to the standard viscosifer formulated with Pac-R. The results showed that the density, specific gravity, pH, yield stress, Gel strength, Plastic Viscosity, and yield point of mud formulated from local materials compared favorably with that of the imported viscosifer. It was observed that an increase in concentration produced a better result. Hence, they could replace the Pac-R considering cost, cutting carrying ability, etc.

scholarly journals Structural Analysis for Wingspan Stent in a Perforator Model

2013 ◽  
Vol 19 (3) ◽  
pp. 271-275 ◽  
Author(s):  
Motoaki Fujimoto ◽  
Yasuhiro Shobayashi ◽  
Koichiro Takemoto ◽  
Satoshi Tateshima ◽  
Fernando Viñuela
Keyword(s):  
Structural Analysis ◽  
Stress Distribution ◽  
Radial Stress ◽  
Circumferential Stress ◽  
Circumferential Direction ◽  
Structural Deformation ◽  
Atheromatous Plaque ◽  
Critical Problem ◽  
Biomechanical Stress

Perforator infarction represents a critical problem after intracranial Wingspan stent. To explore the mechanism of perforator infarction, we simulated the stent-artery interaction at an atheromatous plaque with perforator. Structural deformation and biomechanical stress distribution after stenting were analyzed. High radial stress values were located along the stent struts, which surrounded the area with high circumferential stress. Stretched perforator orifice in a circumferential direction after stenting was simulated. These results show that structural deformation could play a role in the mechanism of perforator occlusion after Wingspan stenting.

scholarly journals Altered stresses and dynamics after single and double annuloplasty ring for aortic valve repair

2020 ◽  
Vol 57 (6) ◽  
pp. 1210-1217
Author(s):  
Leila Louise Benhassen ◽  
Jacob Hesselby Hedensted ◽  
Mona Sharghbin ◽  
Søren Nielsen Skov ◽  
Lisa Carlson Hanse ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Stress Distribution ◽  
Aortic Root ◽  
Radial Stress ◽  
Aortic Annulus ◽  
Aortic Valve Repair ◽  
Valve Repair ◽  
Annuloplasty Ring ◽  
Double Ring ◽  
Single Ring

Abstract OBJECTIVES Aortic valve repair procedures for the treatment of isolated aortic valve insufficiency may be improved by stabilizing the functional aortic annulus using a double annuloplasty ring at the aortic annulus and sinotubular junction (STJ). The objective of this study was to compare the geometrical changes and aortic root stress distribution when using a single subvalvular ring and a double sub- and supravalvular ring in vivo. METHODS Both the single- and double-ring procedures were performed successively in nine 80-kg pigs. Measurements were performed intraoperatively using sonomicrometry crystals in the aortic root to evaluate geometrical changes and annular and STJ force transducers measuring the segmental radial stress distribution. RESULTS The total force in the STJ was significantly reduced after the double-ring procedure from 1.7 ± 0.6 to 0.04 ± 1.1 N (P = 0.001). The double-ring procedure significantly reduced the STJ area from 234.8 ± 37.6 to 147.5 ± 31.8 mm2 (P = 0.001) and expansibility from 17 ± 6% to 8 ± 3% (P = 0.001). With the single-ring procedure, the STJ shape was circular but became more oval with the double-ring procedure. The double-ring procedure did not affect stress distribution or geometry in the aortic annulus. CONCLUSIONS The double-ring procedure stabilized the whole aortic root by reducing radial stress distribution in the STJ more efficiently than the single-ring procedure. Both area and expansibility were reduced with the double-ring procedure. These results confirm the importance of addressing the entire functional aortic annulus for optimal aortic valve repair procedures.

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