Fracture mechanics finite element analysis of debonding crack extension for a single fibre pull-out specimen

Fracture mechanics analysis using the finite element method has been one of the key methodologies to evaluate structural integrity for aging infrastructures such as aircraft, ship, power plants, etc. However, three-dimensional crack analyses for structures with highly complex three-dimensional shapes have not widely been used, because of many technical difficulties such as the lack of enough computational power. The authors have been developing a fracture mechanics analysis system that can deal with arbitrary shaped cracks in three-dimensional structures. The system consists of mesh generation software, a finite element analysis program and a fracture mechanics module. In our system, a Virtual Crack Closure-Integral Method (VCCM) for the quadratic tetrahedral finite elements is adopted to evaluate the stress intensity factors. This system can perform the three-dimensional fracture analyses. Fatigue and SCC crack propagation analyses with more than one cracks of arbitrary complicated shapes and orientations. The rate and direction of crack propagation are predicted by using appropriate formulae based on the stress intensity factors. When the fracture mechanics analysis system is applied to the complex shaped aging structures with the cracks which are modeled explicitly, the size of finite element analysis tends to be very large. Therefore, a large scale parallel structural analysis code is required. We also have been developing an open-source CAE system, ADVENTURE. It is based on the hierarchical domain decomposition method (HDDM) with the balancing domain decomposition (BDD) pre-conditioner. A general-purpose parallel structural analysis solver, ADVENTURE_Solid is one of the solver modules of the ADVENTURE system. In this paper, we combined VCCM for the tetrahedral finite element with ADVENTURE system and large-scale fracture analyses are fully automated. They are performed using the massively parallel super computer ES2 (Earth Simulator 2) which is owned and run by JAMSTEC (Japan Agency for Marine-Earth Science and Technology).

Download Full-text

Fracture Mechanics Fatigue Evaluation of a Flowline Clamp Connector Using Finite Element Modeling of a Crack

Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 27th Annual Student Paper Competition; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD) ◽

10.1115/pvp2019-94077 ◽

2019 ◽

Author(s):

Curtis Sifford ◽

Ali Shirani

Keyword(s):

Finite Element Analysis ◽

Stress Intensity Factor ◽

Finite Element ◽

Fatigue Life ◽

Stress Intensity ◽

Fracture Mechanics ◽

Intensity Factor ◽

Pressure Vessel ◽

Crack Tip ◽

Element Analysis

Abstract This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.

Download Full-text

Fracture Mechanics Fatigue Evaluation of a Flowline Clamp Connector Using Finite Element Modeling of a Crack

Volume 5: High-Pressure Technology; ASME Nondestructive Evaluation, Diagnosis and Prognosis Division (NDPD); Rudy Scavuzzo Student Paper Symposium and 26th Annual Student Paper Competition ◽

10.1115/pvp2018-85164 ◽

2018 ◽

Author(s):

Curtis Sifford ◽

Ali Shirani

Keyword(s):

Finite Element Analysis ◽

Stress Intensity Factor ◽

Finite Element ◽

Fatigue Life ◽

Stress Intensity ◽

Fracture Mechanics ◽

Intensity Factor ◽

Pressure Vessel ◽

Crack Tip ◽

Element Analysis

This paper presents the application of the rules from ASME Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code for a fracture mechanics evaluation to determine the damage tolerance and fatigue life of a flowline clamp connector. The guidelines from API 579-1 / ASME FFS-1 Fitness-For-Service for the stress analysis of a crack-like flaw have been considered for this assessment. The crack tip is modeled using a refined mesh around the crack tip that is referred to as a focused mesh approach in API 579-1 / ASME FFS-1. The driving force method is used as an alternative to the failure assessment diagram method to account for the influence of crack tip plasticity. The J integral is determined using elastic-plastic finite element analysis and converted to an equivalent stress intensity factor to be compared to the fracture toughness of the material. The fatigue life is calculated using the Paris Law equation and the stress intensity factor calculated from the finite element analysis. The allowable number of design cycles is determined using the safety factors required from Division 3 of the ASME Pressure Vessel Code.

Download Full-text

A 3D Finite Element Analysis Study of the Jawbones Response to Osseodensification and Conventional Drilling

Volume 5: Biomedical and Biotechnology ◽

10.1115/imece2020-23669 ◽

2020 ◽

Author(s):

Razan Alaqeely ◽

Mohammad AlDosari ◽

Nadir Babay ◽

Al-Hussain Abdulbari ◽

Ala Ba Hadi ◽

...

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Trabecular Bone ◽

Cone Beam Ct ◽

Primary Stability ◽

Von Mises Stress ◽

Element Analysis ◽

Linear Pattern ◽

Pull Out ◽

Conventional Drilling

Abstract Osseodensification is used to densify natural bone and increase dental implant stability. This work aims to compare, using finite element analysis, the stress generated on different jawbone areas between conventional drilling (OD) and osseodensification drilling (CD). Cone-beam CT scans of four different edentulous patients were obtained. Implant insertion and removal in the four bone models were simulated for the two different drilling techniques. Materials distribution was set as homogeneous throughout each part. In the OD technique, a new densified region was formed with new material properties based on a relation between density and elasticity. Material distribution of the densified regions was assumed to be a non-homogenous linear pattern and its gradual variation complies with the graph-related slope equations. Von-Mises stress for cortical and trabecular bone was significantly higher in the CD model in comparison to their values in the OD, as densified regions have absorbed most of the stresses and restricted their propagation. The same phenomenon was observed in the implant pull-out bone model. The OD technique was found to affect the primary stability of dental implants positively. The bone types present in different jawbone regions react differently to this technique according to the percentage of trabecular bone to cortical bone.

Download Full-text