Electrical self-sensing of impact damage in multiscale hierarchical composites with tailored location of carbon nanotube networks

2018 ◽  
Vol 18 (3) ◽  
pp. 806-818 ◽  
Author(s):  
BKS Isaac-Medina ◽  
A Alonzo-García ◽  
F Avilés
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Electrical Resistance ◽  
Impact Damage ◽  
Multiwall Carbon Nanotubes ◽  
Element Analysis ◽  
The Matrix ◽  
Hierarchical Composites ◽  
Multiwall Carbon

Low-velocity impact damage in multiscale hierarchical composites comprising glass fiber weaves reinforcing a vinyl ester matrix with tailored location of multiwall carbon nanotubes is assessed through the changes of electrical resistance before and after impact. The location of the multiwall carbon nanotubes within the multiscale composite is controlled from manufacturing, rendering two hierarchical architectures. In the first one, as-received glass fiber weaves are used and the multiwall carbon nanotubes are only dispersed within the matrix, while in the second one the multiwall carbon nanotubes are dispersed within the matrix and also bonded to the glass fibers. Spatial electrical resistance maps are able to track the damage progression and growth of damage extension under consecutive impacts and the results are correlated to stresses determined by finite element analysis and ultrasonic C-scanning. The correlation between the electrical mapping and finite element analysis showed that the panels containing multiwall carbon nanotubes on the fiber are more sensitive to delamination and interfacial damage than the ones containing multiwall carbon nanotubes only dispersed within the polymer matrix.

scholarly journals Research on a 3-DOF Motion Device Based on the Flexible Mechanism Driven by the Piezoelectric Actuators

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 578 ◽  
Author(s):  
Bingrui Lv ◽  
Guilian Wang ◽  
Bin Li ◽  
Haibo Zhou ◽  
Yahui Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Machining Process ◽  
Element Analysis ◽  
3D Motion ◽  
Compliance Modeling ◽  
The Matrix ◽  
Static Performance ◽  
Flexible Mechanism

This paper describes the innovative design of a three-dimensional (3D) motion device based on a flexible mechanism, which is used primarily to produce accurate and fast micro-displacement. For example, the rapid contact and separation of the tool and the workpiece are realized by the operation of the 3D motion device in the machining process. This paper mainly concerns the device performance. A theoretical model for the static performance of the device was established using the matrix-based compliance modeling (MCM) method, and the static characteristics of the device were numerically simulated by finite element analysis (FEA). The Lagrangian principle and the finite element analysis method for device dynamics are used for prediction to obtain the natural frequency of the device. Under no-load conditions, the dynamic response performance and linear motion performance of the three directions were tested and analyzed with different input signals, and three sets of vibration trajectories were obtained. Finally, the scratching experiment was carried out. The detection of the workpiece reveals a pronounced periodic texture on the surface, which verifies that the vibration device can generate an ideal 3D vibration trajectory.

Design and analysis of a dual-mode driven parallel XY micromanipulator for micro/nanomanipulations

2012 ◽  
Vol 226 (12) ◽  
pp. 3043-3057 ◽  
Author(s):  
Hui Tang ◽  
Yangmin Li ◽  
Jiming Huang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Properties ◽  
Dynamics Modeling ◽  
Lagrange Equations ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
The Matrix ◽  
High Bandwidth ◽  
Novel Design

This article presents a novel design of a flexure-based, piezoelectric actuated, completely decoupled, high-bandwidth, highresolution, and large stroke parallel XY micromanipulator with two amplification levers. The monolithic mechanism is featured with dual working modes, which meets different kinds of requirements in terms of high resolution and large workspace in micro/nano fields. In order to reduce the displacement loss, the modeling and analysis of bending motion of the levers are conducted; thereafter, compliance and stiffness modeling by employing the matrix method are established. Furthermore, the dynamics modeling and analysis via Lagrange equations are performed to improve the dynamic properties of the mechanism. The simulation results of finite element analysis indicate that the cross-coupling between the two axes is kept to 1.2%; meanwhile, the natural frequency of the mechanism is about 700 Hz, and the amplifier ratio is approximately 2.32. Both theoretical analysis and finite element analysis results well validate the performance of the proposed mechanism.

scholarly journals Vibrational Characteristics of Zigzag, Armchair and Chiral Cantilever Single-Walled Carbon Nanotubes

2013 ◽  
Vol 22 (6) ◽  
pp. 096369351302200
Author(s):  
S.K. Jalan ◽  
B. Nageswara Rao ◽  
S. Gopalakrishnan
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Single Walled Carbon Nanotubes ◽  
Finite Element Models ◽  
Element Analysis ◽  
Single Walled Carbon ◽  
Empirical Relations ◽  
Vibrational Characteristics ◽  
Walled Carbon Nanotubes

Finite element analysis has been performed to study vibrational characteristics of cantilever single walled carbon nanotubes. Finite element models are generated by specifying the C-C bond rigidities, which are estimated by equating energies from molecular mechanics and continuum mechanics. Bending, torsion, and axial modes are identified based on effective mass for armchair, zigzag and chiral cantilever single walled carbon nanotubes, whose Young's modulus is evaluated from the bending frequency. Empirical relations are provided for frequencies of bending, torsion, and axial modes.

Stress Field Numerical Simulation of the Inclusions in Large Rudder Arm Steel Casting

2011 ◽  
Vol 311-313 ◽  
pp. 906-909 ◽  
Author(s):  
Jing Pei Xie ◽  
Ai Qin Wang ◽  
Wen Yan Wang ◽  
Ji Wen Li ◽  
Di Xin Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Field ◽  
Deformation Behavior ◽  
Analysis Software ◽  
Element Analysis ◽  
Metallic Inclusions ◽  
The Matrix ◽  
Steel Castings

The influences of non-metallic inclusions on the quality and properties of the steel not only depended on the quantity of inclusions, but also on the type、shape、size、deformation behavior and distribution condition. By means of ANSYS finite element analysis software, the stress field distribution in the inclusions and the matrix around the inclusions are analyzed under the condition of different kinds of types、shapes、distributions with changeable load in heavy rudder arm steel castings, then micromechanics behavior of inclusions is investigated from angle of macro mechanics.

scholarly journals Dynamic instability of a compound nanocomposite shell

2021 ◽  
Vol 27 (5) ◽  
pp. 60-70
Author(s):  
N.H. Sakhno ◽  
◽  
K.V. Avramov ◽  
B.V. Uspensky ◽  
◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Uniform Distribution ◽  
Critical Pressure ◽  
Natural Frequencies ◽  
Dynamic Instability ◽  
Element Analysis

Free oscillations and dynamic instability due to supersonic airflow pressure are investigated in a functional-gradient compound composite conical-cylindrical shell made of a carbon nanotubes-reinforced material. Nanocomposite materials with a linear distribution of the volumetric fraction of nanotubes over the thickness are considered. Extended mixture rule is used to estimate nanocomposite’s mechanical characteristics. A high-order shear deformation theory is used to represent the shell deformation. The assumed-mode technique, along with a Rayleigh-Ritz method, is applied to obtain the equations of the structure motion. To analyze the compound structure dynamics, a new system of piecewise basic functions is suggested. The pressure of a supersonic flow on the shell is obtained by using the piston theory. An example of the dynamic analysis of a nanocomposite conical-cylindrical shell in the supersonic gas flow is considered. The results of its modal analysis using the Rayleigh-Ritz technique are close to the natural frequencies of the shell obtained by finite element analysis. In this case, finite element analysis can only be used for shells made of material with a uniform distribution of nanotubes over the thickness. The dependence of the natural frequencies of a compound shell on the ratio of the lengths of the conical and cylindrical parts is studied. The dependence of the critical pressure of a supersonic flow on the Mach numbers and the type of carbon nanotubes reinforcement is investigated. Shells with a concentration of nanotubes predominantly near the outer and inner surfaces are characterized by higher values of natural frequencies and critical pressure than the shells with a uniform distribution of nanotubes or with a predominant concentration of nanotubes inside the shell.

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