Fabrication and characterization of microscale sandwich beams

Microscale sandwich beams with cell diameters and wall widths down to 150 and 15 μm, respectively, and having both metallic and polymer/metal cores were produced through fabrication methods that combined photolithography and electrodeposition. Various core structures were used, including some with negative Poisson's ratio. The bending response was investigated and compared with beam-theory predictions. Most of the cores evaluated had sufficient shear stiffness that the bending compliance was relatively high and dominated by the face sheets. Two of the core configurations were “soft” and exhibited behavior governed by core shear. The relative dimensions of the cores evaluated in this study were far from those that minimize the weight, because of fabrication constraints. The development of an ability to make high-aspect ratio cores is an essential next step toward producing structurally efficient, lightweight microscale beams and panels.

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Design and Characterization of Small-Scale Sandwich Beams Fabricated by Photolithography and Electrodeposition

10.1115/imece2000-1103 ◽

2000 ◽

Author(s):

Yuki Sugimura

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Sandwich Beam ◽

Beam Theory ◽

Shear Stiffness ◽

Open Architecture ◽

Small Scale ◽

Sandwich Beams ◽

The Face ◽

Micrometer Size

Abstract Small-scale sandwich beams with core structures having cell diameters and wall widths on the order of 500 μm and 100 μm, respectively, have been produced through fabrication methods that combine photolithography and electrodeposition. Two core configurations have been examined: 1) regular hexagonal honeycomb and 2) high-aspect ratio hexagonal shells having an open architecture. The bending response of the sandwich beams has been examined and compared with the beam theory predictions. Shear stiffness of the honeycomb core was considerably high and therefore the bending behavior was dominated by the face sheets. The bending of the sandwich specimens with the hexagonal shells, on the other hand, was largely dependent on the core. The sandwich beam dimensions investigated in this study have not been optimized for weight minimization and structural efficiency. Further advances in fabrication methods to produce micrometer-size features and high-aspect ratio cores will enable realization of structurally efficient, lightweight sandwich beams and panels that can be used as multifunctional components in small-scale devices.

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Buckling and Postbuckling of Sandwich Beams With Delaminated Faces Based on Higher Order Core Theory

10.1115/imece1999-0129 ◽

1999 ◽

Author(s):

R. F. Li ◽

Y. Frostig ◽

G. A. Kardomateas

Keyword(s):

Nonlinear Distortion ◽

Variational Principles ◽

Vertical Direction ◽

Initial Imperfection ◽

Order Theory ◽

Sandwich Beams ◽

Postbuckling Behavior ◽

The Core ◽

Core Theory ◽

The Face

Abstract Delaminations within the face sheets are often observed when a sandwich structure is exposed to impact loads. The buckling and postbuckling behavior of sandwich beams with delaminated faces is investigated in this work. The governing nonlinear equations, boundary conditions, and continuity conditions are formulated through variational principles. The beam construction consists of upper and lower, metallic or composite laminated symmetric skins, and a soft core of a foam or low strength honeycomb type. A high order theory is used for the core that accounts for the nonlinear distortion of the plane of section of the core and the compressibility in the vertical direction. The delamination considered is an interface crack, in which the substrate includes the transversely flexible core. The case of a debond at one of the skin-core interfaces is also included. The effects of the delamination length and location on the overall and local behavior are examined with an arbitrary initial imperfection.

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Finite Elements for Curved Sandwich Beams

Aeronautical Quarterly ◽

10.1017/s0001925900008027 ◽

1977 ◽

Vol 28 (2) ◽

pp. 123-141 ◽

Cited By ~ 5

Author(s):

P J Holt ◽

J P H Webber

Keyword(s):

Finite Elements ◽

Stiffness Matrix ◽

Test Cases ◽

Sandwich Beams ◽

Honeycomb Core ◽

The Core ◽

The Face ◽

Core Thickness ◽

Displacement Approach ◽

Circular Sandwich Ring

SummaryThe formulation of curved finite elements to represent a two-dimensional circular sandwich ring with honeycomb core and laminated faces is investigated. Assumed stress hybrid and equilibrium methods are found to be easier to employ in this case than the displacement approach. Using these methods, an element stiffness matrix is developed. The approximations of membrane faces and an infinite core normal stiffness are then used to develop simpler elements. Test cases show that these assumptions may become invalid, but that they are adequate for most practical cases where the core thickness to radius ratio and the face thickness to core thickness ratio are both low.

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Fabrication and Characterization of IPMC Actuator for Underwater Micro Robot Propulsor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.575.716 ◽

2014 ◽

Vol 575 ◽

pp. 716-720 ◽

Cited By ~ 3

Author(s):

M.F. Shaari ◽

S.K. Saw ◽

Z. Samad

Keyword(s):

Orientation Angle ◽

Underwater Robot ◽

Metal Composite ◽

Input Frequency ◽

Ionic Polymer ◽

Micro Robot ◽

Polymer Metal ◽

Fabrication And Characterization ◽

Different Thickness

The usage of Ionic Polymer-Metal Composite (IPMC) actuator as the propulsor for underwater robot has been worked out by many scientists and researchers. IPMC actuator had been selected due to its advantages such as low energy consumption, low operation noise and ability to work underwater. This paper presents the fabrication and characterization of the IPMC actuator. The IPMC actuator samples had been fabricated using electroless plating for three different thickness and lengths. The characterization was conducted to determine the influence of the thickness, length, input frequency, drive voltage and orientation angle on the tip force and output frequency. The results show that IPMC thickness has significant influence on the tip force generation and lower input frequency would results wider displacement. The recorded results are essential as future reference in developing the propulsor for the underwater robot.

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Geometrical Nonlinear Effects in the Dynamic Response of Sandwich Beams

Journal of Vibration and Acoustics ◽

10.1115/1.4047069 ◽

2020 ◽

Vol 142 (6) ◽

Author(s):

Itay Odessa ◽

Oded Rabinovitch ◽

Yeoshua Frostig

Keyword(s):

Dynamic Response ◽

Nonlinear Dynamic ◽

High Order ◽

Theory Approach ◽

Nonlinear Frequency ◽

Sandwich Beams ◽

Nonlinear Dynamic Response ◽

The Core ◽

Geometrical Nonlinear ◽

The Face

Abstract The geometrical nonlinear dynamic response of sandwich beams is studied using a dynamic high-order nonlinear model. The model is derived using the variational principle of virtual work and uses the Extended High-Order Sandwich Panel Theory approach with consideration of two interfaces between the three layers. A first-order shear deformation theory is adopted for the face sheets, while the kinematic assumption of high-order small deformations that account for out-of-plane compressibility are considered for the core layer. The nonlinearity of the dynamic model is introduced by considering geometrically nonlinear kinematic relations in the face sheets. The nonlinear kinematic relations and the dynamic modeling aim to evaluate the effects of the two features and their coupling on the response. The nonlinear dynamic response of sandwich beams is studied through two numerical cases and comparison of the nonlinear results with their linear counterparts. The first case looks into the coupling of the global geometrical nonlinear behavior with the dynamic behavior. The second case focuses on the local instability of the face sheets and its interaction with the compressibility of the core in the dynamic response of soft core sandwich beams. The comparison of linear and nonlinear dynamic response in the two cases sheds light on the coupling of the geometrical nonlinear and dynamic behaviors. Among other features, the latter is expressed by nonlinear attractors, higher modes response, nonlinear frequency response, and significant wrinkling response.

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Fabrication and characterization of an ionic polymer-metal composite bending sensor

Macromolecular Research ◽

10.1007/s13233-017-5156-z ◽

2017 ◽

Vol 25 (12) ◽

pp. 1205-1211 ◽

Cited By ~ 9

Author(s):

Dae Seok Song ◽

Dong Gyun Han ◽

Kyehan Rhee ◽

Dong Min Kim ◽

Jae Young Jho

Keyword(s):

Metal Composite ◽

Ionic Polymer Metal Composite ◽

Ionic Polymer ◽

Polymer Metal ◽

Fabrication And Characterization ◽

Bending Sensor

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Fabrication and characterization of smooth high aspect ratio zirconia nanotubes

Chemical Physics Letters ◽

10.1016/j.cplett.2005.05.065 ◽

2005 ◽

Vol 410 (4-6) ◽

pp. 188-191 ◽

Cited By ~ 132

Author(s):

Hiroaki Tsuchiya ◽

Jan M. Macak ◽

Luciano Taveira ◽

Patrik Schmuki

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Fabrication And Characterization

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Fabrication and Characterization of ZrO2 Hollow Spheres

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.253 ◽

2012 ◽

Vol 512-515 ◽

pp. 253-256

Author(s):

Kai Liu ◽

Sa Li ◽

Chang An Wang

Keyword(s):

Zirconium Dioxide ◽

Hollow Spheres ◽

Hollow Microspheres ◽

Formation Mechanisms ◽

Thermal Decomposition Process ◽

The Core ◽

Eds Analysis ◽

Fabrication And Characterization ◽

Wrapping Technique

Zirconium dioxide hollow microspheres were prepared using carbonaceous polysaccharide microspheres as a template through a heterogeneously nucleating wrapping technique. Firstly, carbonaceous microspheres wrapped by ZrO2 were synthesized, and then the obtained precursor was calcinated at 800°C for 2 hours to remove the template. Based on SEM, TEM and EDS analysis, the microstructure, composition and thermal decomposition process of the precursor as well as the final products were investigated. The formation mechanisms of the core-shell structure precursor and the hollow microspheres were also discussed.

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