On the mechanical performance of honeycomb-core sandwich L-joint under bending load: an experimental-numerical study

2021 ◽  
pp. 1-23
Author(s):  
Wenbin Hou ◽  
Jianhua Li ◽  
Lin Sang ◽  
Liang Ying ◽  
Xiao Han
Keyword(s):  
Mechanical Performance ◽  
Numerical Study ◽  
Honeycomb Core ◽  
Bending Load

NUMERICAL STUDY ON THE MECHANICAL PERFORMANCE OF GRAPHENE BRIDGES ON SILLICON THIN FILM TRANSISTORS

2011 ◽  
Author(s):  
Byung-Jae Kim ◽  
Hyeon-Seok Seo ◽  
Won-Ho Lee ◽  
Jong-Hyun Ahn ◽  
Youn-Jea Kim
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Mechanical Performance ◽  
Numerical Study

scholarly journals Mechanical Properties of a Biocomposite Based on Carbon Nanotube and Graphene Nanoplatelet Reinforced Polymers: Analytical and Numerical Study

2021 ◽  
Vol 5 (9) ◽  
pp. 234
Author(s):  
Marwane Rouway ◽  
Mourad Nachtane ◽  
Mostapha Tarfaoui ◽  
Nabil Chakhchaoui ◽  
Lhaj El Hachemi Omari ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Numerical Study ◽  
Turbine Blades ◽  
Natural Fibers ◽  
Computational Method ◽  
Wind Turbine Blades ◽  
Reinforced Polymer ◽  
Analytical Approaches

Biocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer.

scholarly journals A Numerical Study of Railway Ballast Subjected to Direct Shearing Using the Discrete Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Hongyi Zhao ◽  
Jing Chen
Keyword(s):  
Discrete Element Method ◽  
Mechanical Performance ◽  
Numerical Study ◽  
Discrete Element ◽  
Contact Forces ◽  
Angle Of Repose ◽  
Particle Rotation ◽  
Railway Ballast ◽  
Depth Analysis ◽  
Element Method

Railway ballast is a coarse granular material used to carry train loads and provide drainage for the rail tracks. This study presents numerical explorations of the mechanical performance of ballast aggregates subjected to direct shear tests. The discrete element method (DEM) was used to investigate the microscopic characteristics of ballast aggregates during shearing while considering contact distribution, particle rotation, and particle displacement. By testing the angle of repose of ballast aggregates, the parameters for the DEM contact model could be calibrated. Four specimens were prepared and then subjected to different normal pressures. The results show that the contact between ballast particles intensifies in terms of the amount and magnitude as the normal pressure increases. A Fourier analysis was applied to investigate the anisotropy of contact normal and the contact forces for ballast aggregates at different shearing phases. The rotational and translational movements of ballast particles were investigated, and this investigation revealed that particle rotation gradually increased as the shearing propagated. Four regions in the aggregates were identified according to the translational pattern of ballast particles. The results of this research provide an in-depth analysis of microscopic characteristics from a particulate scale.

scholarly journals Compression Properties and Its Prediction of Wood-Based Sandwich Panels with a Novel Taiji Honeycomb Core

Forests ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 886 ◽  
Author(s):  
Jingxin Hao ◽  
Xinfeng Wu ◽  
Gloria Oporto-Velasquez ◽  
Jingxin Wang ◽  
Gregory Dahle
Keyword(s):  
Compression Strength ◽  
Sandwich Structure ◽  
Mechanical Performance ◽  
Compression Modulus ◽  
Honeycomb Core ◽  
Compression Behavior ◽  
Measurement Systems ◽  
Compression Properties ◽  
Entire Structure ◽  
Core Thickness

The transverse compression property is one of most important aspects of the mechanical performance of a sandwich structure with a soft core. An experiment, analytical method and three digital strain measurement systems were applied to investigate the compression behavior and the failure mechanism for a wood-based sandwich structure with a novel Taiji honeycomb core. The results show that the structure of the Taiji honeycomb can improve dramatically on compression strength and modulus of composite compared to that of a traditional hexagonal one. There was no obvious deflection in the transverse direction detected by the three digital images before the buckling of the honeycomb occurred. An analytical equation between the key structure parameters and properties of the composite were applied to predict its threshold stresses and modulus. The properties of the core determine the strength of the entire structure, but the compression strength decreases slightly with an elevated core thickness, and its effect on the compression modulus can be neglected. Both the surface sheets and loading speed have little impact on the compression strength and modulus, respectively.

scholarly journals Experimental and numerical investigation of interface damage in composite L-angle sections under four-point bending

2020 ◽  
Vol 55 (2) ◽  
pp. 187-200
Author(s):  
Xi Zou ◽  
Shibo Yan ◽  
Mikhail Matveev ◽  
James P Rouse ◽  
I Arthur Jones
Keyword(s):  
Numerical Study ◽  
Cohesive Element ◽  
Interlaminar Stresses ◽  
Damage Initiation ◽  
Interface Damage ◽  
Four Point Bending ◽  
Initiation And Propagation ◽  
Bending Load ◽  
Modelling Strategies ◽  
Cohesive Surface

Curved laminates in aero-structures, such as the L-angle sections where webs and flanges meet, are prone to delamination due to high interlaminar stresses in these regions. Some efforts to investigate delamination in these structures can be found in the literature but commonly structures are limited to unidirectional layups or modelling approaches are constrained to the cohesive element based methods. In this work, multi-directional L-angle laminates were manufactured using unidirectional prepregs and tested under four-point bending load conditions to examine the interface damage. Acoustic emission technique was used to assist the capture of damage initiation and propagation. Three interface modelling strategies for predicting delamination, namely cohesive element, cohesive surface and perfectly bonded interface were used in the numerical study. The interface damage behaviour was successfully predicted by the simulation methods and differences among the strategies were compared.

An experimental and numerical study of the expansion forming of a thick-walled microgroove tube

2008 ◽  
Vol 223 (3) ◽  
pp. 689-697 ◽  
Author(s):  
D Tang ◽  
Y Peng ◽  
D Li
Keyword(s):  
Mechanical Performance ◽  
Numerical Study ◽  
Surface Profile ◽  
Processing Parameters ◽  
Forming Process ◽  
Axial Section ◽  
Die Geometry ◽  
Contact Points ◽  
Industrial Sectors ◽  
Full Contact

CO2 refrigerant-based air conditioning and refrigeration (ACR) is an increasing concern in many industrial sectors for its zero ozone depletion potential. One of the major requirements in its application is the forming technology of thick-walled tube according to the extremely high pressure working conditions of the ACR system. This article presents a study on the expansion process joining the thick-walled microgroove copper tube to aluminium fins. Experiments of the forming process have been carried out. Finite-element models are developed to investigate the deformation of overall and local structures. Evaluation of the joining quality along the longitude axis of the tube is first attempted. The agreement of the results on the contact surface profile confirms that the joint is far away from full contact in the axial section. Formation mechanism of the unexpected contact status lies in displacement of the contact points along the section of the fin collar, which is mainly related to the expanding ratio. To improve the forming quality, discussion on processing parameters and die geometry is conducted. Results show that the expanding ratio is the major factor influencing the thermal—mechanical performance of the joint and 2–6 per cent can be the comprehensively beneficial range for a thick-walled ACR tube; average contact pressure can reach 1.76 Mpa under proper set. The results are helpful for improving the energy efficiency ratio performance of the natural refrigerant-based system.

scholarly journals Mechanical Performance of Honeycomb Sandwich Structures Using Three-Point Bend Test

2019 ◽  
Vol 9 (2) ◽  
pp. 3955-3958
Author(s):  
T. Subhani
Keyword(s):  
Mechanical Performance ◽  
Sandwich Structures ◽  
Bend Test ◽  
Core Material ◽  
Honeycomb Core ◽  
Adhesive Film ◽  
Honeycomb Sandwich ◽  
Point Bend Test ◽  
Three Point Bend Test ◽  
Point Bend

In this study, honeycomb sandwich structures were prepared and tested. Facesheets of sandwich structures were manufactured by carbon fiber epoxy matrix composites while Nomex® honeycomb was used as core material. An epoxy-based adhesive film was used to bond the composite facesheets with honeycomb core. Four different curing temperatures ranging from 100oC to 130oC were applied with curing times of 2h and 3h. Three-point bend test was performed to investigate the mechanical performance of honeycomb sandwich structures and thus optimize the curing parameters. It was revealed that the combination of a temperature of 110oC along with a curing time of 2h offered the optimum mechanical performance together with low damage in honeycomb core and facesheets.

A Numerical Study on Mechanical Performance and Hemolysis for Different Types of Centrifugal Blood Pumps

2015 ◽  
Author(s):  
Minwook Chang ◽  
Nahmkeon Hur ◽  
Mohammad Moshfeghi ◽  
Seongwon Kang ◽  
Wonjung Kim ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Numerical Study ◽  
Type A ◽  
Von Mises Stress ◽  
Lower Amount ◽  
Type D ◽  
Cone Type ◽  
Blood Pumps ◽  
Different Types ◽  
Impeller Type

Centrifugal blood pumps have to be considered from both mechanical and biomechanical aspects. While, evaluations of mechanical factors, such as performance curve, are straightforward, biomechanical parameters, such as hemolysis indices, are still indistinct. Hence, different mathematical models and computational methods have been employed for the evaluation of hemolysis indices. This article aims to investigate four different types of centrifugal blood pumps from both mechanical and biomechanical aspects. The pumps are cone-type impeller (Type-A), channel-type impeller with shroud (Type-B), open impeller without shroud (Type-C) and shrouded impeller-type (Type-D). The CFD simulations are conducted using standard k-ε turbulence model in multiple reference frame (MRF) method. Various values for rotational speed and flow rate are studied. The streamlines clearly show the effects of impeller geometry on flow patterns. It is also demonstrated that in all of the models, the areas of the recirculation have high value of von Mises stress. In addition, the effect of the volute in the Type-D on the pressure distribution and streamline smoothness is clearly observed. In another part, the modified index of hemolysis (MIH) calculated based on Eulerian approach is investigated for three predefined conditions of extracorporeal membrane oxygenation (ECMO), ventricular assist device (VAD), and full-load. The results reveal that the Type-A and Type-D have the highest and lowest MIH values, respectively in all of the predefined conditions. In addition, all of the pumps generate lower amount of hemolysis when they are operated in VAD condition.

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