scholarly journals FRP pipeline performance in tensional and torsional S-lay installation loads

2021 ◽  
Vol 1201 (1) ◽  
pp. 012044
Author(s):  
Dimitrios Pavlou
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Numerical Results ◽  
Stacking Sequence ◽  
Loading Conditions ◽  
Axial Tension ◽  
Filament Wound ◽  
Torsional Loads ◽  
Maximum Stresses ◽  
Main Factor

Abstract The loading conditions of a composite pipeline is the main factor for its dimensioning. During S-lay offshore installation of multilayered FRP pipelines, severe tensional and torsional loads take place in the above sea part of the pipeline. Since the wall pipe is multilayered and the material properties of the laminae and the laminate is anisotropic, the maximum stresses depend on the stacking sequence. In the present work, an analytical model is proposed for calculating the capacity of multilayered FRP pipelines to carry axial and torsional loads. Numerical results for typical multilayered filament wound E-Glass/Epoxy pipelines under axial tension and torsion are provided and discussed.

scholarly journals A Study of the Effective Lifetime of Aluminum Buckets Used in Blood Bank Centrifuges

2017 ◽  
Vol 7 (4) ◽  
pp. 1797-1801
Author(s):  
M. F. Tafti ◽  
R. Golestani ◽  
M. Salari
Keyword(s):  
Blood Bank ◽  
Numerical Results ◽  
Loading Conditions ◽  
Element Analysis ◽  
Fatigue Lifetime ◽  
Effective Lifetime ◽  
Safety Requirements ◽  
Good Consistency ◽  
Operating Cycles ◽  
Maximum Stresses

Rotating parts of blood bank centrifuges are under heavy mechanical cyclic stresses due to their centrifugal loading conditions. Estimating the effective lifetime for these parts is very important for their application. Providing safety requirements for these components is mandatory in blood transfusion centers (BTC). Failure occurs in the engineering parts for both loading conditions of steady and cyclic. The fatigue phenomenon is the main reason for mechanical failures at least in 90 % of fractures during operation. In this paper, the effects of fatigue caused by centrifugal loadings on aluminum buckets produced by the Iranian Sina Ebtekar Company (ISECo) are investigated experimentally. In this study, 48 aluminum buckets are chosen from a set of 500 buckets. The numbers of service of the samples are accounted for a period of 7 months. Finite element analysis, FEM, is done for an aluminum bucket and the relevant maximum stresses due to the rotating loads of centrifugation are determined. Analyzing the numerical results and using the fatigue, lifetime diagrams according to the number of operating cycles is presented for the samples. A good consistency is observed between the experimental and numerical results. Based on the results, a new correlation is presented for estimating the aluminum bucket’s lifetime made by ISECO.

scholarly journals Multi-stable composite twisting structure for morphing applications

2012 ◽  
Vol 468 (2141) ◽  
pp. 1230-1251 ◽  
Author(s):  
X. Lachenal ◽  
P. M. Weaver ◽  
S. Daynes
Keyword(s):  
Analytical Model ◽  
Material Properties ◽  
Degrees Of Freedom ◽  
Design Parameters ◽  
Engineering Structures ◽  
The Past ◽  
Wide Range ◽  
Morphing Structure ◽  
Low Mass ◽  
Unstable States

Conventional shape-changing engineering structures use discrete parts articulated around a number of linkages. Each part carries the loads, and the articulations provide the degrees of freedom of the system, leading to heavy and complex mechanisms. Consequently, there has been increased interest in morphing structures over the past decade owing to their potential to combine the conflicting requirements of strength, flexibility and low mass. This article presents a novel type of morphing structure capable of large deformations, simply consisting of two pre-stressed flanges joined to introduce two stable configurations. The bistability is analysed through a simple analytical model, predicting the positions of the stable and unstable states for different design parameters and material properties. Good correlation is found between experimental results, finite-element modelling and predictions from the analytical model for one particular example. A wide range of design parameters and material properties is also analytically investigated, yielding a remarkable structure with zero stiffness along the twisting axis.

FEBio finite element model of a pediatric cervical spine

2021 ◽  
pp. 1-7
Author(s):  
Sean M. Finley ◽  
J. Harley Astin ◽  
Evan Joyce ◽  
Andrew T. Dailey ◽  
Douglas L. Brockmeyer ◽  
...  
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Finite Element Model ◽  
Material Properties ◽  
Surgical Simulation ◽  
Element Model ◽  
Axial Stiffness ◽  
Published Data ◽  
Axial Tension ◽  
Flexion Extension

OBJECTIVE The underlying biomechanical differences between the pediatric and adult cervical spine are incompletely understood. Computational spine modeling can address that knowledge gap. Using a computational method known as finite element modeling, the authors describe the creation and evaluation of a complete pediatric cervical spine model. METHODS Using a thin-slice CT scan of the cervical spine from a 5-year-old boy, a 3D model was created for finite element analysis. The material properties and boundary and loading conditions were created and model analysis performed using open-source software. Because the precise material properties of the pediatric cervical spine are not known, a published parametric approach of scaling adult properties by 50%, 25%, and 10% was used. Each scaled finite element model (FEM) underwent two types of simulations for pediatric cadaver testing (axial tension and cardinal ranges of motion [ROMs]) to assess axial stiffness, ROM, and facet joint force (FJF). The authors evaluated the axial stiffness and flexion-extension ROM predicted by the model using previously published experimental measurements obtained from pediatric cadaveric tissues. RESULTS In the axial tension simulation, the model with 50% adult ligamentous and annulus material properties predicted an axial stiffness of 49 N/mm, which corresponded with previously published data from similarly aged cadavers (46.1 ± 9.6 N/mm). In the flexion-extension simulation, the same 50% model predicted an ROM that was within the range of the similarly aged cohort of cadavers. The subaxial FJFs predicted by the model in extension, lateral bending, and axial rotation were in the range of 1–4 N and, as expected, tended to increase as the ligament and disc material properties decreased. CONCLUSIONS A pediatric cervical spine FEM was created that accurately predicts axial tension and flexion-extension ROM when ligamentous and annulus material properties are reduced to 50% of published adult properties. This model shows promise for use in surgical simulation procedures and as a normal comparison for disease-specific FEMs.

Simplified LBB Guidance: Stage 1 — Development of a New Software Tool and Initial Scoping Calculations

2018 ◽  
Author(s):  
Peter Gill ◽  
John Sharples ◽  
Chris Aird
Keyword(s):  
Fracture Toughness ◽  
Material Properties ◽  
Software Tool ◽  
Pipe Material ◽  
Loading Conditions ◽  
Design Rules ◽  
Inner Radius ◽  
Inner Diameter ◽  
Stage 1 ◽  
Leak Before Break

This study is focussed on establishing more simplified Leak-before-Break (LbB) guidance for inclusion into Section III.11 of the R6 procedure. The approach adopted has involved the development of a universal software tool for LbB simplified assessments which can be used to perform initial scoping calculations to demonstrate typical LbB cases. It is envisaged that this simplified methodology will enable plant assessment engineers to be more informed on which sites on plant are likely to have LbB successfully applied and to be able to undertake LbB assessments in a more simplistic way than is currently available. Using the developed software tool, a range of LbB calculations for different cracks and loading conditions have been performed to provide guidance on where LbB is more likely to be applied on plant. Loading conditions include primary and secondary stresses, where through-wall changes have been accounted for. The pipe geometries included in this study have been defined by the inner radius and the wall thickness, calculated by minimum pipe thickness required according to meet the design rules of ASME III. The pipe inner radius varies from 40mm to 200mm (80mm to 400mm inner diameter (ID)). All pipe outer diameters are less than 0.5m. All cracks considered in this study are through-wall and circumferential. Pipe material properties are chosen to be broadly representative of an Austenitic Stainless Steel, where the fracture toughness varies from 100 to 180MPa√m and the yield stress is 150MPa.

scholarly journals Structural optimization in ESAC: annals 2011

2014 ◽  
Vol 5 ◽  
pp. A09
Author(s):  
Ji-Hong Zhu ◽  
Wei-Hong Zhang
Keyword(s):  
Topology Optimization ◽  
Structural Optimization ◽  
Material Properties ◽  
Numerical Results ◽  
Multiphase Materials ◽  
And Topology ◽  
Effective Material Properties

The purpose of this paper is to give an overall introduction of the structural optimization research works in ESAC group in 2011. Four main topics are involved, i.e. 1) topology optimization with multiphase materials, 2) integrated layout and topology optimization, 3) prediction of effective material properties and 4) composite design. More detailed techniques and some numerical results are also presented and discussed here.

Study of Pullout Performance of Self-Tapping Screws for Human Bone

2011 ◽  
Author(s):  
Zhijun Wu ◽  
Sayed A. Nassar ◽  
Xianjie Yang
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Analytical Model ◽  
Material Properties ◽  
Pedicle Screws ◽  
Pullout Strength ◽  
Bone Material ◽  
Synthetic Bone ◽  
Failure Propagation ◽  
Device Applications

The study investigates the pullout strength of self-tapping pedicle screws using analytical, finite element, and experimental methodologies with focus on medical device applications. The stress distribution and failure propagation around implant threads in the synthetic bone during the pullout process, as well as the pullout strength of pedicle screws, are explored. Based on the FEA results, an analytical model for the pullout strength of the pedicle screw is constructed in terms of the synthetic bone material properties, screw size, and implant depth. The characteristics of pullout behavior of self-tapping pedicle screws are discussed. Both the analytical model and finite element results are validated using experimental techniques.

Challenges in Joining Thermoset Composite Piping

2010 ◽  
Author(s):  
Avinash Parashar ◽  
Pierre Mertiny
Keyword(s):  
Adhesive Bonding ◽  
Lap Joints ◽  
Fiber Reinforced Polymers ◽  
Potential Candidate ◽  
Loading Conditions ◽  
Adhesively Bonded ◽  
Technical Literature ◽  
Filament Wound ◽  
Piping Systems ◽  
Mechanical Properties And Corrosion

The aim of this paper is to examine solutions and challenges related to joining thermoset composite piping. Fiber reinforced polymers (FRP) have been used in piping systems for more than 40 years. Higher specific mechanical properties and corrosion resistance of FRP make them a potential candidate for replacing metallic piping structures. Despite the advantages associated with FRP, their application is still limited due to, in part, unsatisfactory methods for joining composite subcomponents and inadequate knowledge of failure mechanism under different loading conditions. Adhesively bonded joints are attractive for many applications since they offer integrated sealing, minimal part count and do not require pipe extremities with complex geometries such as threads or bell and spigot configurations. So far, the majority of work reported in the technical literature on adhesively bonded pipe joints is concerned with lap joints employing wrapping techniques to produce overlap sleeve connections. More recently, a joining technique was proposed that replaces the wrapping technique with filament-wound overlap sleeve couplers that are adhesively bonded to the pipe extremities. In the present article, various joining techniques for FRP piping through adhesive bonding are discussed, and damage mechanisms under different loading conditions are examined.

Multi-level patient-specific modelling of the proximal femur. A promising tool to quantify the effect of osteoporosis treatment

2009 ◽  
Vol 367 (1895) ◽  
pp. 2079-2093 ◽  
Author(s):  
Leen Lenaerts ◽  
G. Harry van Lenthe
Keyword(s):  
Bone Strength ◽  
Material Properties ◽  
Bone Structure ◽  
Structural Information ◽  
Response To Treatment ◽  
Patient Specific ◽  
Loading Conditions ◽  
Femoral Bone ◽  
Fe Modelling ◽  
Specific Loading

Preventing femoral fractures is an important goal in osteoporosis research. In order to evaluate a person's fracture risk and to quantify response to treatment, bone competence is best assessed by bone strength. Finite-element (FE) modelling based on medical imaging is considered a very promising technique for the assessment of in vivo femoral bone strength. Over the past decades, a number of different FE models have been presented focusing on the effect of several methodological aspects, such as mesh type, material properties and loading conditions, on the precision and accuracy of these models. In this paper, a review of this work is presented. We conclude that moderate to good predictions can be made, especially when the models are tuned to specific loading scenarios. However, there is room for improvement when multiple loading conditions need to be evaluated. We hypothesize that including anisotropic material properties is the first target. As a proof of the concept, we demonstrate that the main orientation of the femoral bone structure can be calculated from clinical computed tomography scans. We hypothesize that this structural information can be used to estimate the anisotropic bone material properties, and that in the future this could potentially lead to a greater predictive value of FE models for femoral bone strength.

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