scholarly journals Application of the Finite Element Method to the Quasi-Static Thermoelastic Analysis of Prestress in Multilayer Pressure Vessels

1994 ◽  
Vol 116 (3) ◽  
pp. 254-260 ◽  
Author(s):  
J. Rasty ◽  
P. Tamhane
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Construction Material ◽  
Pressure Vessels ◽  
Construction Process ◽  
The Finite Element Method ◽  
Closed Form Solutions ◽  
Distribution Of Stress ◽  
Section Analysis ◽  
Element Method

Multilayered wrapped vessel technology utilizes the compressive prestress induced during construction process to gain a considerable advantage over the monoblock vessels. The compressive prestress allows for more efficient use of construction material and more uniform distribution of stress throughout the vessel’s cross section. Analysis of the magnitude of prestress throughout the vessel’s thickness has been previously reported (Rasty, 1988). However, one major idealization in such analysis has been the assumption that the magnitude of induced prestress is constant around the circumference of the vessel. In this research, thermoelastic finite element method was utilized to simulate the construction process of one layer of the vessel. It was concluded that the compressive residual stress induced by the weld shrinkage varies through the circumference of the vessel by as much as 13.5 percent. Circumferential distributions of the prestress are presented and compared to the closed-form solutions (constant prestress assumption) in earlier works.

scholarly journals A 1D Model for Predicting Heat and Moisture Transfer through a Hemp-Concrete Wall Using the Finite-Element Method

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6903
Author(s):  
Maroua Benkhaled ◽  
Salah-Eddine Ouldboukhitine ◽  
Amer Bakkour ◽  
Sofiane Amziane
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Moisture Transfer ◽  
Construction Material ◽  
Climatic Conditions ◽  
Vapor Permeability ◽  
Transfer Model ◽  
The Finite Element Method ◽  
Concrete Wall ◽  
Element Method

Plant-based concrete is a construction material which, in addition to having a very low environmental impact, exhibits excellent hygrothermal comfort properties. It is a material which is, as yet, relatively unknown to engineers in the field. Therefore, an important step is to implement reliable mass-transfer simulation methods. This will make the material easy to model, and facilitate project design to deliver suitable climatic conditions. In recent decades, numerous studies have been carried out to develop models of the coupled transfers of heat, air and moisture in porous building envelopes. Most previous models are based on Luikov’s theory, considering mass accumulation, air and total pressure gradient. This theory considers the porous medium to be homogeneous, and therefore allows for hygrothermal transfer equations on the basis of the fundamental principles of thermodynamics. This study presents a methodology for solving the classical 1D (one-dimensional) HAM (heat, air, and moisture) hygrothermal transfer model with an implementation in MATLAB. The resolution uses a discretization of the problem according to the finite-element method. The detailed solution has been tested on a plant-based concrete. The energy and mass balances are expressed using measurable transfer quantities (temperature, water content, vapor pressure, etc.) and coefficients expressly related to the macroscopic properties of the plant-based concrete (thermal conductivity, specific heat, water vapor permeability, etc.), determined experimentally. To ensure this approach is effective, the methodology is validated on a test case. The results show that the methodology is robust in handling a rationalization of the model whose parameters are not ranked and not studied by their degree of importance.

FFS Assessment of Pressurized Equipment Utilizing a Thickness Mapping Tool

2016 ◽  
Author(s):  
Benjamin Hantz ◽  
Venkata M. K. Akula ◽  
John Leroux
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Response Prediction ◽  
Accurate Estimate ◽  
Pressure Vessels ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Level 3 ◽  
Level 1 ◽  
Element Method

For pressure vessels, loss of thickness detected during scheduled maintenance utilizing UT scans can be assessed based on Level 1 or 2 analyses as per API 579 guidelines. However, Level 1 and 2 analyses can point to excessively conservative assessments. Level – 3 assessments utilizing the finite element method can be performed for a more accurate estimate of the load carrying capacity of the corroded structure. However, for a high fidelity structural response prediction using the finite element method, the characteristics of the model must be accurately represented. Although the three nonlinearities, namely, the geometric, material, and contact nonlinearities can be adequately included in a finite element analysis, procedures to accurately include the thickness measurements are not readily available. In this paper, a tool to map thicknesses obtained from UT scans onto a shell based finite element models, to perform Level – 3 analyses is discussed. The tool works in conjunction with Abaqus/CAE and is illustrated for two different structures following the elastic-plastic analysis procedure outlined in the API 579 document. The tool is intended only as a means to reduce the modeling time associated with mapping thicknesses. The results of the analyses and insights gained are presented.

scholarly journals Mechanobiological Analysis of Molar Teeth with Carious Lesions through the Finite Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
R. A. Hernández-Vázquez ◽  
Betriz Romero-Ángeles ◽  
Guillermo Urriolagoitia-Sosa ◽  
Juan Alejandro Vázquez-Feijoo ◽  
Rodrigo Arturo Marquet-Rivera ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Tissue Level ◽  
The Finite Element Method ◽  
Dental Tissues ◽  
Carious Lesions ◽  
Treatment Plans ◽  
Molar Teeth ◽  
Distribution Of Stress ◽  
Element Method

The analysis of the distribution of stress in dental organs is a poorly studied area. That is why computational mechanobiological analysis at the tissue level using the finite element method is very useful to achieve a better understanding of the biomechanics and the behaviour of dental tissues in various pathologies. This knowledge will allow better diagnoses, customize treatment plans, and establish the basis for the development of better restoration materials. In the present work, through the use of high-fidelity biomodels, computational mechanobiological analyses were performed on four molar models affected with four different degrees of caries, which are subjected to masticatory forces. With the analyses performed, it is possible to observe that the masticatory forces that act on the enamel are not transmitted to the dentin and to the bone and periodontal ligament to protect the nerve, as it happens in a healthy dental organ. With the presence of decay, these forces are transmitted partly to the pulp. The reactions to the external loads on the dental organs depend on the advances of the carious lesion that they present, since the distribution of stresses is different in a healthy tooth.

Static Analysis of Buttress Threads Using the Finite Element Method

1992 ◽  
Vol 114 (2) ◽  
pp. 209-212 ◽  
Author(s):  
A. Chaaban ◽  
M. Jutras
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Pressure ◽  
Load Distribution ◽  
Pressure Vessels ◽  
Stress Index ◽  
The Finite Element Method ◽  
Thread Root ◽  
Root Stress ◽  
Element Method

The finite element method has been used to investigate the stress field in threaded end closures of thick-walled high pressure vessels. A set of elastic analyses of vessels with 5, 8, 11, 15, 20 and 25 standard Buttress threads was used to propose a method for predicting the load distribution along the length of the thread. Root stress index factors in the region of the first three active threads are also included. The results of the present work contribute to the development of the new division of the ASME Pressure Vessel Code which is related to thick-walled high pressure vessels.

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