A Random Unit Cell Finite Element Model for the Elastic Modulus of Concrete Composites with Interfacial Transition Zone

2009 ◽  
Author(s):  
S. Abdelmoumen ◽  
E. Bellenger ◽  
B. Lynge ◽  
M. Quéneudec-t'Kint
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Model ◽  
Transition Zone ◽  
Element Model ◽  
Interfacial Transition Zone ◽  
Unit Cell

scholarly journals An Inverse Method to Predict NEMS Beam Properties From Natural Frequencies

2020 ◽  
Vol 87 (6) ◽  
Author(s):  
Alyssa T. Liem ◽  
Atakan B. Ari ◽  
J. Gregory McDaniel ◽  
Kamil L. Ekinci
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Boundary Conditions ◽  
Finite Element Model ◽  
Axial Load ◽  
Natural Frequencies ◽  
Axial Loading ◽  
Element Model ◽  
Normalized Error ◽  
Beam Parameters

Abstract This paper presents a method to simultaneously predict the elastic modulus, axial load, and boundary conditions of a nanoelectromechanical system (NEMS) beam from a minimum of two measured natural frequencies. The proposed method addresses the challenges of the inverse problem at the nano scale, which include high natural frequencies, small geometric beam dimensions, and measurements limited to natural frequencies. The method utilizes a finite element model of an Euler–Bernoulli beam under axial loading to predict the response of the beam with axial loading and flexible boundary conditions. By expressing the finite element model in terms of dimensionless beam parameters, the proposed method may be applied to nano scale beams while maintaining numerical stability of the finite element equation of motion. With the stabilized finite element model, the NEMS beam properties are predicted by iterating through values of dimensionless beam parameters until the normalized error between predicted and measured natural frequencies is minimized. A key feature of the proposed method is the simultaneous prediction of the elastic modulus during the iterative search, resulting in a reduction of the search space and significant computational savings. Additionally, the proposed method readily accommodates an arbitrary number of measured natural frequencies without the reformulation of procedures and analyses. Numerical examples are presented to illustrate the proposed method’s ability to predict the elastic modulus, axial load, and boundary conditions. The proposed method is applied to experimental measurements of a NEMS beam, where the normalized error between predicted and measured natural frequencies is reduced below 10−3.

scholarly journals A Novel Optimized Finite Element Model of Lenke 1 Adolescent Idiopathic Scoliosis Based on Dynamic Flexibility in Vivo

2021 ◽  
Author(s):  
Shengbo Niu ◽  
Jinyi Bai ◽  
Huan Yang ◽  
Dongsheng Zhang ◽  
Jianghong Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Adolescent Idiopathic Scoliosis ◽  
Intervertebral Disc ◽  
Finite Element Model ◽  
Characteristic Curve ◽  
Element Model ◽  
Traction Load ◽  
The Finite Element Model

Abstract Bacground: It is of great significance to optimize the finite element model by spinal flexibility of adolescent idiopathic scoliosis (AIS) patients. The elastic modulus of the intervertebral disc is of critical importance in determining the overall flexibility of the spine. The aim of the present study was to optimize the finite element model of Lenke 1 AIS based on the dynamic flexibility in vivo by matching the optimal elastic modulus of the intervertebral disc.Methods: The Cobb angles under different longitudinal traction loads of one patient with Lenke 1 AIS were dynamically measured by using a spine morphometer with a posture sensor to plot the Cobb angle-longitudinal traction load characteristic curve. A 3D finite element model of the patient was established. The patient’s Cobb angle-longitudinal traction load characteristic curve was used as the dynamic flexibility in vivo to determine the optimal intervertebral disc elastic modulus of the model. Results: The dynamic flexibility curve in vivo of one Lenke 1 AIS patient was successfully obtained, and the patient’s optimal elastic modulus of the intervertebral disc for the finite element model was 5 MPa according to the dynamic flexibility curve in vivo.Conclusions: The use of dynamic flexibility in vivo to optimize the finite element model can provide a new perspective and approach for model optimization, which can reproduce the biomechanical characteristics in vivo of AIS patients.

scholarly journals Numerical investigation of the mechanical properties of the additive manufactured bone scaffolds fabricated by FDM: the effect of layer penetration and post-heating

2017 ◽  
Author(s):  
Saman Naghieh ◽  
Mohammad Reza Karamooz-Ravari ◽  
Mohsen Badrossamay ◽  
Ehsan Foroozmehr
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Elastic Modulus ◽  
Numerical Methods ◽  
Finite Element Model ◽  
Compression Test ◽  
Element Model ◽  
Element Analysis ◽  
Bone Scaffolds

In recent years, thanks to additive manufacturing technology, researchers have gone towards the optimization of bone scaffolds for the bone reconstruction. Bone scaffolds should have appropriate biological as well as mechanical properties in order to play a decisive role in bone healing. Since the fabrication of scaffolds is time consuming and expensive, numerical methods are often utilized to simulate their mechanical properties in order to find a nearly optimum one. Finite element analysis is one of the most common numerical methods that is used in this regard. In this paper, a parametric finite element model is developed to assess the effects of layers penetration׳s effect on inter-layer adhesion, which is reflected on the mechanical properties of bone scaffolds. To be able to validate this model, some compression test specimens as well as bone scaffolds are fabricated with biocompatible and biodegradable poly lactic acid using fused deposition modeling. All these specimens are tested in compression and their elastic modulus is obtained. Using the material parameters of the compression test specimens, the finite element analysis of the bone scaffold is performed. The obtained elastic modulus is compared with experiment indicating a good agreement. Accordingly, the proposed finite element model is able to predict the mechanical behavior of fabricated bone scaffolds accurately. In addition, the effect of post-heating of bone scaffolds on their elastic modulus is investigated. The results demonstrate that the numerically predicted elastic modulus of scaffold is closer to experimental outcomes in comparison with as-built samples.

A Different Approach for Obtaining the Shear Moduliof a Composite Material

2020 ◽  
Vol 70 (12) ◽  
pp. 4470-4476
Keyword(s):  
Finite Element ◽  
Composite Material ◽  
Elastic Modulus ◽  
Shear Modulus ◽  
Finite Element Model ◽  
Element Model ◽  
Layered Composite ◽  
Element Analysis ◽  
Shear Elastic Modulus ◽  
Elastic Characteristics

In recent years the composites materials gained a major importance in all fields of engineering, because they offer a successful replacement for classical materials conferring similar elastic-mechanical properties to metal or non-metal alloys presenting several advantages such as reduced mass, chemical resistance etc. Considering this, during the design, dull knowledge of the elastic-mechanical characteristics is of high importance. The present paper aims to create a finite element model able to predict the shear elastic modulus of a double-layered composite material based on the elastic characteristics of its constituents. For this, once the elastic characteristics of the constituents determined, they could be used in the finite element analysis obtaining consequently the shear modulus for the composite material. Also, the shear elastic modulus of the resultant composite was determined experimentally. The results of the finite element model were compared to the experimental values in order to validate the finite element analyses results. Keywords: composites, fiberglass, shear modulus, FEM

Research on Strain Transfer of Embedded BOTDA Sensors Analyzed by FEM

2013 ◽  
Vol 357-360 ◽  
pp. 1473-1479
Author(s):  
Yan Qiao ◽  
Chuan Zhi Sun ◽  
Biao Zhang
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Model ◽  
Matrix Material ◽  
Element Model ◽  
Analysis Software ◽  
Element Analysis ◽  
Strain Transfer ◽  
Fiber Coating ◽  
Bonding Material

in this paper, the theory of strain transfer of embedded BOTDA sensors was introduced. For the sensing fiber with coating and jacket used in project, its finite element model was built by ANSYS infinite element analysis software. And for the embedded fiber, the influences affected by elastic modulus and thickness of the fiber coating and jacket and elastic modulus of matrix material were analyzed. For the surface bonded fiber, the influences affected by elastic modulus, width and thickness of the bonding material were analyzed, and the results were compared with the results of theory.

Tension-bending analysis of flexible pipe by a repeated unit cell finite element model

2019 ◽  
Vol 64 ◽  
pp. 401-420 ◽  
Author(s):  
Troels Vestergaard Lukassen ◽  
Egil Gunnarsson ◽  
Steen Krenk ◽  
Kristian Glejbøl ◽  
Anders Lyckegaard ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Unit Cell ◽  
Flexible Pipe ◽  
Bending Analysis ◽  
Repeated Unit

scholarly journals Experimental and numerical investigation of the effect of holes on the springback in cold roll forming of UHSS

2021 ◽  
Author(s):  
Zhi-min Liu ◽  
Pan Zhang ◽  
xiaoli liu ◽  
ming zhang ◽  
qiang ma ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Model ◽  
High Strength ◽  
Element Model ◽  
Tensile Tests ◽  
Roll Forming ◽  
Cold Roll Forming ◽  
Cold Roll ◽  
Forming Precision

Abstract Ultra-high strength steel (UHSS) pre-notched sections are getting growing popularity in the automotive industry with the development of automotive lightweight. However, the springback of UHSS products is large, and the existence of holes also has an effect on the springback. Accurate prediction of springback of UHSS pre-notched products in cold roll forming ( CRF ) is a key issue to be solved. In this paper, the effect of holes on the springback of UHSS in CRF is discussed by simulation and experiment. The finite element model of pre-notched car threshold was constructed, and its accuracy was validated by continuous CRF experiment. The mathematical model of variable elastic modulus determined by tensile tests of martensite (MS) 1300 was applied in finite element model. The accuracy of springback was improved by 15% in the hole region by using variable elastic modulus . Several forming schemes were designed to research the effect of different features on the springback in the hole region. The results show that the existence of holes reduces the springback and the effect is different at different positions of the car threshold. The springback in the hole region decreases with the increase of the number of stands, the strip thickness and the hole diameter, and with the decrease of the distance between stands and the distance between holes. This study provides a help for reducing the influence of holes on the springback and improving the forming precision of pre-notched sections in the actual production of CRF.

scholarly journals Analysis for the heat transfer of fully tempered vacuum glazing based on the thermal resistance model and finite element model

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879598 ◽  
Author(s):  
Dongfang Hu ◽  
Yichen Li ◽  
Chang Liu ◽  
Yanbing Li
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Heat Conduction ◽  
Finite Element Model ◽  
Thermal Resistance ◽  
Element Model ◽  
Unit Cell ◽  
Hertzian Contact ◽  
Total Thermal Resistance ◽  
Vacuum Glazing

The fully tempered vacuum glazing, consisting of two fully tempered glass plates detached through a limited vacuum medium (below 0.01 Pa), is presented. The heat transfer through fully tempered vacuum glazing is complex, including heat conduction, thermal radiation, and convection. To analyze heat conduction through a stainless steel support ball, the thermal resistance of the support ball is established based on Hertzian contact model. And the total thermal resistance of the unit cell with one support ball is defined. The three-dimensional finite element model for a center unit cell of fully tempered vacuum glazing is simulated to validate the result of the total thermal resistance. The simulation transmission U-values are 0.26 W/m2 K. Meanwhile, the simulation transmission U-values of entire fully tempered vacuum glazing are 0.84 W/m2 K without frame insulation.

Sign in / Sign up

Export Citation Format

Share Document