scholarly journals Frequency-domain homogenization for impedance characterization of litz-wire transformers in 2-D finite element models

2016 ◽  
Author(s):  
Korawich Niyomsatian ◽  
Jeroen Van den Keybus ◽  
Ruth V. Sabariego ◽  
Johan Gyselinck
Keyword(s):  
Finite Element ◽  
Frequency Domain ◽  
Finite Element Models ◽  
Impedance Characterization

Viscoelastic characterization of soft tissue from dynamic finite element models

2008 ◽  
Vol 53 (22) ◽  
pp. 6569-6590 ◽  
Author(s):  
Hani Eskandari ◽  
Septimiu E Salcudean ◽  
Robert Rohling ◽  
Jacques Ohayon
Keyword(s):  
Finite Element ◽  
Soft Tissue ◽  
Finite Element Models ◽  
Dynamic Finite Element

Advancements in the Detection and Sizing of “Pinhole” Metal Loss

2014 ◽  
Author(s):  
Wilson Santamaria ◽  
Martin Bluck
Keyword(s):  
Finite Element ◽  
United Kingdom ◽  
Metal Loss ◽  
Finite Element Models ◽  
Test Program ◽  
Joint Paper ◽  
The United Kingdom ◽  
Software Models ◽  
The World

At IPC 2010 PII Pipeline Solutions (PII) presented the paper “VALIDATION OF LATEST GENERATION MFL IN-LINE INSPECTION TECHNOLOGY LEADS TO IMPROVED DETECTION AND SIZING SPECIFICATION FOR PINHOLES, PITTING, AXIAL GROOVING AND AXIAL SLOTTING”1, IPC 2010-31124. The suggestion was that this improvement would allow operators to make more informed pipeline integrity decisions in future. In the 4 years since this paper was presented many hundreds of runs have been completed with this latest generation MFL ILI technology, capturing information on tens of thousands of kilometers of pipe, and generating a significant volume of dig verification data. In collaboration with Oil & Gas pipeline operators around the world this growing dig verification database has been utilized to improve software models, algorithms, & analysis processes to validate and further enhance system detection, sizing, & reporting capabilities. This paper focuses on the recent collaboration between ExxonMobil and PII, to investigate system capabilities with respect to “Pinholes”, to address a known threat to a specific pipeline in the United Kingdom. This paper will describe the: • Evolution of the “Pinhole” specification that captured the interest of ExxonMobil. • Use of Finite Element models to predict entitlement for characterization of “Pinhole” type defects • Detail of and results from the ExxonMobil sponsored test program that was conducted in early 2013 • The in-line inspection, analysis report, and dig verification that followed for the pipeline in question. This joint paper, prepared and presented in collaboration by ExxonMobil & PII, will reflect the perspective and synergy of the Pipeline Owner/Operator and the ILI Vendor.

scholarly journals Investigation of the Compressive Viscoelastic Properties of Brain Tissue Under Time and Frequency Dependent Loading Conditions

2021 ◽  
Author(s):  
Weiqi Li ◽  
Duncan E. T. Shepherd ◽  
Daniel M. Espino
Keyword(s):  
Finite Element ◽  
Brain Tissue ◽  
Time Domain ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Series Representation ◽  
Experimental Tests ◽  
Finite Element Models ◽  
Frequency Dependent

AbstractThe mechanical characterization of brain tissue has been generally analyzed in the frequency and time domain. It is crucial to understand the mechanics of the brain under realistic, dynamic conditions and convert it to enable mathematical modelling in a time domain. In this study, the compressive viscoelastic properties of brain tissue were investigated under time and frequency domains with the same physical conditions and the theory of viscoelasticity was applied to estimate the prediction of viscoelastic response in the time domain based on frequency-dependent mechanical moduli through Finite Element models. Storage and loss modulus were obtained from white and grey matter, of bovine brains, using dynamic mechanical analysis and time domain material functions were derived based on a Prony series representation. The material models were evaluated using brain testing data from stress relaxation and hysteresis in the time dependent analysis. The Finite Element models were able to represent the trend of viscoelastic characterization of brain tissue under both testing domains. The outcomes of this study contribute to a better understanding of brain tissue mechanical behaviour and demonstrate the feasibility of deriving time-domain viscoelastic parameters from frequency-dependent compressive data for biological tissue, as validated by comparing experimental tests with computational simulations.

Characterization of Material Behavior of the Fused Deposition Modeling Processed Parts

2017 ◽  
Author(s):  
Madhukar Somireddy ◽  
Aleksander Czekanski
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Fused Deposition Modeling ◽  
Material Behavior ◽  
Constitutive Law ◽  
Finite Element Models ◽  
Strength Parameters ◽  
Fused Deposition ◽  
Deposition Modeling

In the present research, one of the additive manufacturing techniques, fused deposition modeling (FDM) fabricated parts are considered for investigation of their material behavior. The FDM process is a layer upon layer deposition of a material to build three dimensional parts and such parts behave as laminated composite structures. Each layer of the part acts as a unidirectional fiber reinforced lamina, which is treated as an orthotropic material. The mesostructure of a part fabricated via fused deposition modeling process is accounted for in the investigation of its mechanical behavior. The finite element (FE) procedure for characterization of a material constitutive law for the FDM processed parts is presented. In the analysis, the mesostructure of the part obtained via FDM process is replicated in the finite element models. Finite element models of tensile specimens are developed with mesostructure that would be obtained from FDM process, then uniaxial tensile test simulations are conducted. The elastic moduli of a lamina are calculated from the linear analysis and the strength parameters are obtained from the nonlinear finite element analysis. The present work provides a FE methodology to find elastic moduli and strength parameters of a FDM processed part by accounting its mesostructure in the analysis.

Evaluation of Structural and Biomechanical Characterization of Implant for Cranial Restoration

2019 ◽  
Vol 9 (7) ◽  
pp. 898-903
Author(s):  
Fu-Hui Tsai ◽  
Han-Yi Cheng
Keyword(s):  
Finite Element ◽  
3D Printing ◽  
3D Model ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Clinical Applications ◽  
Finite Element Models ◽  
Critical Factors ◽  
Circular Structure

The objective this research was to investigate the biomechanical properties of various structures and thicknesses of implants for cranial restoration. A three-dimensional (3D) printing (3DP) technique has been applied in factories for several decades, but it was only recently introduced to the dental field less than 10 years ago. The structures of pre-shaped cranial mesh implants are critical factors for clinical applications. Many previous studies used finite element models to investigate for implants, but few examined a 3D model for pre-shaped cranial mesh implants with different structures and thicknesses. 3D cranial models were reconstructed using computer tomography to simulate preshaped cranial mesh implants under physical impacts. Data indicated that the stress significantly decreased when implants with greater thicknesses were used. Moreover, the implant with a circular structure created a relatively smaller stress that was approximately 7% lower compared to the implant with a triangular structure. As described above, the results of the present study demonstrate that 3DP-Ti is a reliable material of implants for cranial restoration.

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