Modelling the dynamic compressive response of syntactic foam with hierarchical cell structure

2021 ◽  
Vol 124 ◽  
pp. 104248
Author(s):  
Zhiqiang Fan ◽  
Fei Zhang ◽  
Bingbing Zhang ◽  
Tianming He ◽  
Peng Xu ◽  
...  
Keyword(s):  
Cell Structure ◽  
Syntactic Foam ◽  
Compressive Response

Numerical Simulation of Compressive Response of Open-Cell Aluminum Foams

2014 ◽  
Vol 1016 ◽  
pp. 156-160
Author(s):  
Margarida Machado ◽  
Nuno Peixinho
Keyword(s):  
Cell Structure ◽  
Body Centered Cubic ◽  
The Finite Element Method ◽  
Compressive Properties ◽  
Aluminum Foams ◽  
Uniform Size ◽  
Open Cell ◽  
Compressive Response ◽  
A Cell ◽  
Pore Arrangement

The compressive properties of open-cell aluminum foams are numerically studied using representative volume elements by means of the finite element method. Four face body centered cubic cell arrangements are analyzed, namely uniform-size with spherical pores and dual-size with spherical pores. The results demonstrated that a cell configuration with dual-size pore arrangement presents improved properties for applications subjected to compression loading. This is attributed to the introduction of secondary pores in the cell structure that provide an increase in the specific stiffness and strength of open-cell aluminum foams.

scholarly journals STUDY OF POLYMER SYNTACTIC AND FOAM MATERIALS OF NEW GENERATION WITH IMPROVING OPERATIONAL CHARACTERISTICS

2017 ◽  
Vol 60 (2) ◽  
pp. 67
Author(s):  
Larisa V. Chursova ◽  
Igor I. Sokolov ◽  
Anna I. Lukina
Keyword(s):  
Phenolic Resin ◽  
Cell Structure ◽  
Syntactic Foam ◽  
Polymeric Materials ◽  
Nitrile Rubber ◽  
Small Areas ◽  
Foaming Process ◽  
Operational Characteristics ◽  
Powder Particles ◽  
New Generation

The article deals with the creation of lightweight syntactic polymeric materials of new generation with the improved complex operational and special properties. The preparation of composition and technology polymeric syntactic foam based on cyanat resin having the higher operational and special properties, compared by analog material, was shown.  The production of such material has the different steps: the synthesis of cyanat resin with request rheological properties; blending the cyanat resin with glass microsphere for prepare the material with request homogenous properties; the prepare of roll syntactic polymeric materials having the thickness 2 mm. For preparing the material with request thickness we used the calendric technology; cutting the roll spheroplastic material on sample workpeace; the molding of spheroplastic. The application spheroplastic can significantly increase both absolute and specific characteristics of multilayer structures compared to design with cell. Also, the preparation of polymeric phenolic foam, based on phenolic resin, modified by rubber, having close-cell structure and higher operational properties, was shown. For foaming process the foam obtained semifinished product are not prefabricated as individual pellets or crushed powder as generally accepted in the preparation of foams brand FC, and rolled in the form of solid sheets, the total mass chosen with a given density of the obtained foam. The resulting foam originally monolithic semi eliminated the possibility of forming foam at foaming various small areas between individual pellets (or powder particles). Thereby, it reduces the overall porosity in the resulting foam. It was found that resole resins (containing novolac oligomer) poor fit together with a nitrile rubber. In addition, a combination of product of nitrile rubber with phenol resoles SF-3021K and with a novolac resin in all investigated ratios doesn’t allow to obtain high quality foam structure having a density less than 150 kg / m3. Only by combining a mixture of nitrile rubber and oligomeric compositions (resole (SF-342A) with novolak (SF-010), it is possible to obtain foams with a density from 80 to 150 kg / m3. For citation:Chursova L.V., Sokolov I.I., Lukina A.I. Study of polymer syntactic and foam materials of new generation with improving operational characteristics. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N2. P. 67-73.

Quasi-Static and High Strain Rate Compressive Response of Injection-Molded Cenosphere/HDPE Syntactic Foam

JOM ◽  
2016 ◽  
Vol 68 (7) ◽  
pp. 1861-1871 ◽  
Author(s):  
B. R. Bharath Kumar ◽  
Ashish Kumar Singh ◽  
Mrityunjay Doddamani ◽  
Dung D. Luong ◽  
Nikhil Gupta
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Strain ◽  
Syntactic Foam ◽  
Compressive Response ◽  
Injection Molded

Dynamic Compressive Response and Failure Behavior of an Epoxy Syntactic Foam

2004 ◽  
Vol 38 (11) ◽  
pp. 915-936 ◽  
Author(s):  
Bo Song ◽  
Weinong Chen ◽  
Danny J. Frew
Keyword(s):  
Syntactic Foam ◽  
Failure Behavior ◽  
Compressive Response

scholarly journals Effect of Resin and Blocked/Unblocked Hardener Mixture on the Production of Epoxy Foams with CO2 Blocked Hardener in Batch Foaming Process

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 793
Author(s):  
Christian Bethke ◽  
Sandra A. Sanchez-Vazquez ◽  
Daniel Raps ◽  
Gökhan Bakis ◽  
Simon Bard ◽  
...  
Keyword(s):  
Size Distribution ◽  
Cell Size ◽  
Time Window ◽  
Cell Structure ◽  
Syntactic Foam ◽  
Diglycidyl Ether ◽  
Cell Size Distribution ◽  
Foaming Process ◽  
Expansion Time ◽  
Batch Foaming

The present study focuses on the processing and properties of epoxy foams by the use of CO2 blocked hardener N-aminoethylpiperazine (B-AEP) and different resins. Although some studies described the foaming with carbamates, little attention has been given to the interaction of resin properties (such as viscosity) on the foaming performance. Therefore, two resins, diglycidyl ether of bisphenol-A (DGEBA) and epoxy novolac (EN), as well as their 50:50 blend, were foamed with B-AEP and unblocked/blocked AEP hardener mixtures in a batch foaming process. Furthermore, the commercially available chemical blowing agent para-toluenesulfonyl hydrazide (TSH) was used as a benchmark for commonly used chemical blowing agents. The lowest density in this study was reached by the DGEBA+B-AEP system in the range of 215 kg/m3 with the drawback of an inhomogeneous cell structure and high cell size distribution. The best cell morphology and lowest cell size distribution was reached with the EN+15:85% unblocked:blocked hardener mixture, resulting in a density in the range of 394 kg/m3. A syntactic foam was achieved by a DGEBA+50:50% unblocked:blocked hardener mixture with a density of around 496 kg/m3. It was found that a higher viscosity of the resin lead to an increase in the density and a decrease in the cell size distribution range as a result of a closer expansion time window.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Cell structure properties during in situ creep experiments in the H.V.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 574-575
Author(s):  
D. Caillard ◽  
J.L. Martin
Keyword(s):  
Tensile Axis ◽  
Cell Structure ◽  
Image Intensifier ◽  
Foil Thickness ◽  
Average Cell Size ◽  
Average Cell ◽  
Voltage Electron ◽  
Steady Stage ◽  
Stationary Creep

The behaviour of the dislocation substructure during the steady stage regime of creep, as well as its contribution to the creep rate, are poorly known. In particular, the stability of the subboundaries has been questioned recently, on the basis of experimental observations |1||2| and theoretical estimates |1||3|. In situ deformation experiments in the high voltage electron microscope are well adapted to the direct observation of this behaviour. We report here recent results on dislocation and subboundary properties during stationary creep of an aluminium polycristal at 200°C.During a macroscopic creep test at 200°C, a cell substructure is developed with an average cell size of a few microns. Microsamples are cut out of these specimens |4| with the same tensile axis, and then further deformed in the microscope at the same temperature and stain rate. At 1 MeV, one or a few cells can be observed in the foil thickness |5|. Low electron fluxes and an image intensifier were used to reduce radiation damage effects.

High-pressure freezing and freeze substitution of plant tissue

1992 ◽  
Vol 50 (1) ◽  
pp. 748-749
Author(s):  
William P. Sharp ◽  
Robert W. Roberson
Keyword(s):  
High Pressure ◽  
Cell Structure ◽  
Leaf Tissue ◽  
Freeze Substitution ◽  
Crystal Formation ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Components ◽  
Cold Metal ◽  
Brome Grass

The aim of ultrastructural investigation is to analyze cell architecture and relate a functional role(s) to cell components. It is known that aqueous chemical fixation requires seconds to minutes to penetrate and stabilize cell structure which may result in structural artifacts. The use of ultralow temperatures to fix and prepare specimens, however, leads to a much improved preservation of the cell’s living state. A critical limitation of conventional cryofixation methods (i.e., propane-jet freezing, cold-metal slamming, plunge-freezing) is that only a 10 to 40 μm thick surface layer of cells can be frozen without distorting ice crystal formation. This problem can be allayed by freezing samples under about 2100 bar of hydrostatic pressure which suppresses the formation of ice nuclei and their rate of growth. Thus, 0.6 mm thick samples with a total volume of 1 mm3 can be frozen without ice crystal damage. The purpose of this study is to describe the cellular details and identify potential artifacts in root tissue of barley (Hordeum vulgari L.) and leaf tissue of brome grass (Bromus mollis L.) fixed and prepared by high-pressure freezing (HPF) and freeze substitution (FS) techniques.

Structural integrity after cold storage of human epidermal model in hypothermosol: A correlative ultrastructural and fluorescent assay

1994 ◽  
Vol 52 ◽  
pp. 270-271
Author(s):  
Henry H. Eichelberger ◽  
John G. Baust ◽  
Robert G. Van Buskirk
Keyword(s):  
Cold Storage ◽  
Structural Integrity ◽  
Culture Media ◽  
Cell Structure ◽  
Natural State ◽  
Sodium Cacodylate ◽  
Ruthenium Tetroxide ◽  
Cacodylate Buffer ◽  
Before And After

For research in cell differentiation and in vitro toxicology it is essential to provide a natural state of cell structure as a benchmark for interpreting results. Hypothermosol (Cryomedical Sciences, Rockville, MD) has proven useful in insuring the viability of synthetic human epidermis during cold-storage and in maintaining the epidermis’ ability to continue to differentiate following warming.Human epidermal equivalent, EpiDerm (MatTek Corporation, Ashland, MA) consisting of fully differentiated stratified human epidermal cells were grown on a microporous membrane. EpiDerm samples were fixed before and after cold-storage (4°C) for 5 days in Hypothermosol or skin culture media (MatTek Corporation) and allowed to recover for 7 days at 37°C. EpiDerm samples were fixed 1 hour in 2.5% glutaraldehyde in sodium cacodylate buffer (pH 7.2). A secondary fixation with 0.2% ruthenium tetroxide (Polysciences, Inc., Warrington, PA) in sodium cacodylate was carried out for 3 hours at 4°C. Other samples were similarly fixed, but with 1% Osmium tetroxide in place of ruthenium tetroxide. Samples were dehydrated through a graded acetone series, infiltrated with Spurrs resin (Polysciences Inc.) and polymerized at 70°C.

Sign in / Sign up

Export Citation Format

Share Document