scholarly journals Compliant Nano-Pliers as a Biomedical Tool at the Nanoscale: Design, Simulation and Fabrication

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1087
Author(s):  
Alessio Buzzin ◽  
Serena Cupo ◽  
Ennio Giovine ◽  
Giampiero de Cesare ◽  
Nicola Pio Belfiore
Keyword(s):  
Aspect Ratio ◽  
Degrees Of Freedom ◽  
Fabrication Process ◽  
Design Approach ◽  
Curved Beams ◽  
Sem Images ◽  
Flexure Hinges ◽  
Comb Drives ◽  
Mask Fabrication

This paper presents the development of a multi-hinge, multi-DoF (Degrees of Freedom) nanogripper actuated by means of rotary comb drives and equipped with CSFH (Conjugate Surface Flexure Hinges), with the goal of performing complex in-plane movements at the nanoscale. The design approach, the simulation and a specifically conceived single-mask fabrication process are described in detail and the achieved results are illustrated by SEM images. The first prototype presents a total overall area of (550 × 550) μm2, an active clamping area of (2 × 4) μm2, 600 nm-wide circular curved beams as flexible hinges for its motion and an aspect ratio of about 2.5. These features allow the proposed system to grasp objects a few hundred nanometers in size.

An Exact Three-Dimensional Beam Element With Nonuniform Cross Section

2010 ◽  
Vol 77 (6) ◽  
Author(s):  
M. Jafari ◽  
M. J. Mahjoob
Keyword(s):  
Cross Section ◽  
Stiffness Matrix ◽  
Degrees Of Freedom ◽  
Direct Method ◽  
Three Dimensional ◽  
Curved Beams ◽  
Element Analysis ◽  
Shear Loads ◽  
Line Passing ◽  
Exact Stiffness Matrix

In this paper, the exact stiffness matrix of curved beams with nonuniform cross section is derived using direct method. The considered element has two nodes and 12 degrees of freedom, with three forces and three moments applied at each node. The noncoincidence effect of shear center and center of area is also considered in this element. The deformations of the beam are due to bending, torsion, tensile, and shear loads. The line passing through center of area is a general three-dimensional curve and the cross section properties may change arbitrarily along it. The method is extended to deal with distributed loads on the curved beams. The stiffness matrix of some selected types of beams is determined by this method. The results are compared (where possible) with previously published results, simple beam finite element analysis and analytic solution. It is shown that the determined stiffness matrix is exact and that any type of beam can be analyzed by this method.

Fabrication of Ultra Thick Ferromagnetic Structures in Silicon

2004 ◽  
Author(s):  
Debbie G. Jones ◽  
Albert P. Pisano
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Saturation Magnetization ◽  
Silicon Wafer ◽  
Fabrication Process ◽  
Sem Images ◽  
Deep Reactive Ion Etching ◽  
Scanning Electron

A novel fabrication process is presented to create ultra thick ferromagnetic structures in silicon. The structures are fabricated by electroforming NiFe into silicon templates patterned with deep reactive ion etching (DRIE). Thin films are deposited into photoresist molds for characterization of an electroplating cell. Results show that electroplated films with a saturation magnetization above 1.6 tesla and compositions of approximately 50/50 NiFe can be obtained through agitation of the electrolyte. Scanning electron microscopy (SEM) images show that NiFe structures embedded in a 500 μm thick silicon wafer are realized and the roughening of the mold sidewalls during the DRIE aids in adhesion of the NiFe to the silicon.

Absolute Nodal Coordinate Formulation With Vector-Strain Transformation for High Aspect Ratio Wings

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Keisuke Otsuka ◽  
Yinan Wang ◽  
Kanjuro Makihara
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Degrees Of Freedom ◽  
Absolute Nodal Coordinate Formulation ◽  
Lattice Method ◽  
Absolute Nodal Coordinate ◽  
Aeroelastic Analysis ◽  
Strain Transformation ◽  
Highly Nonlinear ◽  
Analytical Approaches

Abstract High aspect ratio wings are potential candidates for use in atmospheric satellites and civil aircraft as they exhibit a low induced drag, which can reduce the fuel consumption. Owing to their slender and light weight configuration, such wings undergo highly flexible aeroelastic static and dynamic deformations that cannot be analyzed using conventional linear analysis methods. An aeroelastic analysis framework based on the absolute nodal coordinate formulation (ANCF) can be used to analyze the static and dynamic deformations of high aspect ratio wings. However, owing to the highly nonlinear elastic force, the statically deformed wing shape during steady flight cannot be efficiently obtained via static analyses. Therefore, an ANCF with a vector-strain transformation (ANCF-VST) was proposed in this work. Considering the slender geometry of high aspect ratio wings, the nodal vectors of an ANCF beam element were transformed to the strains. In this manner, a constant stiffness matrix and reduced degrees-of-freedom could be generated while capturing the highly flexible deformations accurately. The ANCF-VST exhibited superior convergence performance and accuracy compared to those of analytical approaches and other nonlinear beam formulations. Moreover, an aeroelastic analysis flow coupling the ANCF-VST and an aerodynamic model based on the unsteady vortex lattice method was proposed to perform the static and dynamic analyses successively. The proposed and existing aeroelastic frameworks exhibited a good agreement in the analyses, which demonstrated the feasibility of employing the proposed framework to analyze high aspect ratio wings.

Some General Considerations on the Natural Mode Technique

1969 ◽  
Vol 73 (700) ◽  
pp. 361-368 ◽  
Author(s):  
J. H. Argyris ◽  
D. W. Scharpf
Keyword(s):  
Degrees Of Freedom ◽  
General Procedure ◽  
Practical Significance ◽  
Natural Mode ◽  
Curved Beams ◽  
Normal Forces ◽  
Natural Modes ◽  
Straight Beam ◽  
Mode Technique ◽  
Made In

We continue our fundamental discourse on the natural modes in an element and extend our considerations to large displacements. First, we present a general procedure for establishing the so-called geometrical stiffness k G , when the natural modes of the complete element are given. The theory is a substantial generalisation and clarification of the method initially given in refs. 2 and 3 and shows that in establishing the modification to the transformation matrix a N it is necessary to ignore the contribution of the natural modes, which cause rotation at the nodal points but no displacement there. The point is subtle and was not made in ref. 2, although the applications given there are correct. As an example, the geometrical stiffness of a straight beam in space with all degrees of freedom is established. There follows the extension of the geometrical stiffness concept to a sub-element. This is of great practical significance for two reasons. First, it allows to derive the geometrical stiffness of elements of complex shape and behaviour, e.g. curved beams in space subjected to normal forces, bending moments and torque.

Silicon IC compatible LIGA mask-fabrication process

1997 ◽  
Vol 4 (1) ◽  
pp. 7-11 ◽  
Author(s):  
K. Suzuki ◽  
S. Sugiyama
Keyword(s):  
Fabrication Process ◽  
Mask Fabrication

The Conceptual Design of Differential Mechanisms

2013 ◽  
Vol 284-287 ◽  
pp. 973-978
Author(s):  
Chia Chun Chu
Keyword(s):  
Conceptual Design ◽  
Design Process ◽  
Degrees Of Freedom ◽  
Geometric Constraints ◽  
The Other ◽  
Design Approach ◽  
Process Step ◽  
Two Degrees Of Freedom ◽  
Number Synthesis

The purpose of this paper is to present a design approach based on the geometric constraints of joints for synthesizing differential mechanisms with two degrees-of-freedom, including some mechanisms with the same functions but distinct structures. The concept of virtual axes is presented. And, there are five steps in the design process. Step 1 is to decide fundamental entities by the properties of existing mechanisms and the technique of number synthesis, and 10 suitable fundamental entities of differential mechanisms are available. Step 2 is to compose geometric constraints, and 14 items are obtained. Step 3 is to compose links, and 15 items are derived. Step 4 is to assign fixed constraints for inputs or outputs, and 15 results are found. The final step is to particularize the obtained events by the properties of existing mechanisms and the structures of fundamental entities. As a result, 8 feasible results for differential mechanisms with two degrees-of-freedom and two basic loops are obtained in which 2 are existing designs and the other 6 are novel.

Effect of aspect ratio, surface modification and compatibilizer on the mechanical and thermal properties of ldpe-mwcnt nanocomposites

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarfraz H. Abbasi ◽  
Abdulhadi A. Al-Juhani ◽  
Anwar Ul-Hamid ◽  
Ibnelwaleed A. Hussein
Keyword(s):  
Thermal Properties ◽  
Aspect Ratio ◽  
Yield Strength ◽  
Chemical Modification ◽  
Ultimate Strength ◽  
Multiwall Carbon Nanotubes ◽  
Mechanical And Thermal Properties ◽  
Sem Images ◽  
Elongation At Break ◽  
Ldpe Composites

AbstractIn this work, nanocomposites of low density polyethylene (LDPE) / multiwall carbon nanotubes (MWCNTs) were prepared using melt blending. The effects of CNT aspect ratio, CNT loading, CNT chemical modification and the presence of a compatibilizer (maleated polyethylene) on morphology, mechanical and thermal properties of the CNT/LDPE composites were studied. Different MWCNTs were used: long CNT (LCNT); COOH modified CNT (MCNT) and short CNT (SCNT). FE-SEM images of produced nanocomposites show agglomeration of the MWCNTs. Addition of compatibilizer to both LCNT and MCNT nanocomposites improved their dispersion in the LDPE matrix. Yield strength and modulus increased with loading of various MWCNTs. However, ultimate strength, percent elongation and toughness reduced significantly for CNT loadings of 2% CNT and higher. The addition of maleated PE resulted in improvements of Young’s modulus, yield strength and ultimate strength but no impact on elongation at break or toughness. Addition of compatibilizer did not affect the crystallinity of the produced nanocomposites. In general, the use of CNT with high aspect ratio and the addition of compatibilizer and chemical modification improved the dispersion of MWCNTs and consequently improved most of the mechanical properties except elongation at break and toughness.

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