Characterization of the Stiffness Properties of Honeycomb Core Structures via an Homogenization Technique

Simplified Approach to Calculating Geometric Stiffness Properties of Tread Pattern Elements

Tire Science and Technology ◽

10.2346/1.2135265 ◽

2003 ◽

Vol 31 (3) ◽

pp. 132-158 ◽

Cited By ~ 6

Author(s):

R. E. Okonieski ◽

D. J. Moseley ◽

K. Y. Cai

Keyword(s):

Development Process ◽

Functional Design ◽

Simplified Approach ◽

Tire Industry ◽

Geometric Stiffness ◽

Stiffness Properties ◽

Engineering Parameters ◽

Net To Gross ◽

Significant Effort

Abstract The influence of tread designs on tire performance is well known. The tire industry spends significant effort in the development process to create and refine tread patterns. Creating an aesthetic yet functional design requires characterization of the tread design using many engineering parameters such as stiffness, moments of inertia, principal angles, etc. The tread element stiffness is of particular interest because of its use to objectively determine differences between tread patterns as the designer refines the design to provide optimum levels of performance. The tread designer monitors the change in stiffness as the design evolves. Changes to the geometry involve many attributes including the number of sipes, sipe depth, sipe location, block element edge taper, nonskid depth, area net-to-gross, and so forth. In this paper, two different formulations for calculating tread element or block stiffness are reviewed and are compared to finite element results in a few cases. A few simple examples are shown demonstrating the basic functionality that is possible with a numerical method.

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Conceptual Design of a New Multi-Component Test Bench for the Dynamic Characterization of Running Specific Prostheses

Proceedings ◽

10.3390/proceedings2020049075 ◽

2020 ◽

Vol 49 (1) ◽

pp. 75 ◽

Cited By ~ 1

Author(s):

Nicola Petrone ◽

Gianfabio Costa ◽

Gianmario Foscan ◽

Francesco Bettella ◽

Gianluca Migliore ◽

...

Keyword(s):

Test Bench ◽

Reaction Force ◽

Dynamic Characterization ◽

Prosthetic Foot ◽

Load Combination ◽

Stiffness Properties ◽

Component Test ◽

Static And Dynamic Loads ◽

Force Components

Stiffness properties of running specific prostheses (RSP) for Paralympic runners are fundamental in the selection of the optimal running prosthetic foot (RPF) for sprint and jump events, depending on the athlete’s anthropometry and characteristics. RPFs are J-shaped or C-shaped, clamped to the socket or the pylon of the prosthetic leg. The aim of this work was to develop a test bench suitable for the static and dynamic characterization of a running prosthetic feet (RPF). Based on the evidence that the ground reaction force components change their relative orientation to the pylon or socket during the stance, loads were resolved in the socket reference frame and a multi-component test bench was designed and constructed. Two perpendicular actuators can apply static and dynamic loads to the foot while contacting a surrogate ground inclined at different angles. The preliminary tests show how the alignment, load combination, and ground angle can affect RPF stiffness curves.

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Characterization of PETG honeycomb core applied in energy absorbers as protection to vehicle lateral collisions

10.5151/simea2021-pap43 ◽

2021 ◽

Author(s):

Rita de Cassia Silva ◽

Alessandro Borges de Sousa Oliveira ◽

Gabriel Martins Castro

Keyword(s):

Honeycomb Core ◽

Energy Absorbers

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In-Plane Thermal Characterization of Fiberglass/Phenolic Honeycomb Core through an Experimental-Numerical Approach

American Society for Composites 2018 ◽

10.12783/asc33/26112 ◽

2018 ◽

Author(s):

HOOMAN SHAHVERDI ◽

SURESH KESHAVANARAYANA ◽

AAKASH KOTHARE ◽

PING TEOH ◽

CHARLES YANG ◽

...

Keyword(s):

Thermal Characterization ◽

Numerical Approach ◽

Honeycomb Core

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Manufacturing and Characterization of Highly Environmentally Friendly Sandwich Composites from Polylactide Cores and Flax-Polylactide Faces

Polymers ◽

10.3390/polym13030342 ◽

2021 ◽

Vol 13 (3) ◽

pp. 342

Author(s):

Diego Lascano ◽

Rene Guillen-Pineda ◽

Luis Quiles-Carrillo ◽

Juan Ivorra-Martínez ◽

Rafael Balart ◽

...

Keyword(s):

Sandwich Structures ◽

Great Influence ◽

Weight Ratio ◽

Environmentally Friendly ◽

Compression Molding ◽

Hot Compression ◽

Honeycomb Core ◽

The Core ◽

Core Thickness

This work focuses on the manufacturing and characterization of highly environmentally friendly lightweight sandwich structures based on polylactide (PLA) honeycomb cores and PLA-flax fabric laminate skins or facings. PLA honeycombs were manufactured using PLA sheets with different thicknesses ranging from 50 to 500 μm. The PLA sheets were shaped into semi-hexagonal profiles by hot-compression molding. After this stage, the different semi-hexagonal sheets were bonded together to give hexagonal panels. The skins were manufactured by hot-compression molding by stacking two Biotex flax/PLA fabrics with 40 wt% PLA fibers. The combined use of temperature (200 °C), pressure, and time (2 min) allowed PLA fibers to melt, flow, and fully embed the flax fabrics, thus leading to thin composite laminates to be used as skins. Sandwich structures were finally obtained by bonding the PLA honeycomb core with the PLA-flax skins using an epoxy adhesive. A thin PLA nonwoven was previously attached to the external hexagonal PLA core, to promote mechanical interlock between the core and the skins. The influence of the honeycomb core thickness on the final flexural and compression properties was analyzed. The obtained results indicate that the core thickness has a great influence on the flexural properties, which increases with core thickness; nevertheless, as expected, the bonding between the PLA honeycomb core and the skins is critical. Excellent results have been obtained with 10 and 20 mm thickness honeycombs with a core shear of about 0.60 and facing bending stresses of 31–33 MPa, which can be considered as candidates for technical applications. The ultimate load to the sample weight ratio reached values of 141.5 N·g−1 for composites with 20 mm thick PLA honeycombs, which is comparable to other technical composite sandwich structures. The bonding between the core and the skins is critical as poor adhesion does not allow load transfer and, while the procedure showed in this research gives interesting results, new developments are necessary to obtain standard properties on sandwich structures.

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PHYSICAL AND MECHANICAL CHARACTERIZATION OF PLANCHONELLA PACHYCARPA WOOD SPECIES FOR USE IN STRUCTURAL PURPOSE

Wood Research ◽

10.37763/wr.1336-4561/66.2.267276 ◽

2021 ◽

Vol 66 (2) ◽

pp. 267-276

Author(s):

Vinicius Borges De Moura Aquino ◽

Marcus Vinicius Pereira De Freitas ◽

Claudia Queiroz De Vasconcelos ◽

João Paulo Boff Almeida ◽

Felipe Nascimento Arroyo ◽

...

Keyword(s):

Mechanical Properties ◽

Apparent Density ◽

Wood Species ◽

Regression Models ◽

Physical And Mechanical Properties ◽

Stiffness Properties ◽

Longitudinal Elastic Modulus ◽

Structural Purpose ◽

Brazilian Standard

This research aimed to characterize the wood species Goiabão (Planchonella pachycarpa), following the precepts set forth in the Brazilian standard ABNT NBR 7190, as well as to evaluate the possibility of estimating physical and mechanical properties, using the analysis of variance (ANOVA) as a function of apparent density, and also to estimate the stiffness properties as a function of the respective strength property. The physical and mechanical properties were considered adequate for the use of this wood for structural purposes, being classified in class C40. According to the results of the regression models, it is possible to estimate the tensile strength parallel to the fibers as a function of the apparent density. It was also possible to estimate the longitudinal elastic modulus in the compression parallel to the fibers as a function of the compressive strength parallel to the fibers.

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Characterization of Nomex honeycomb core constituent material mechanical properties

Composite Structures ◽

10.1016/j.compstruct.2014.06.033 ◽

2014 ◽

Vol 117 ◽

pp. 255-266 ◽

Cited By ~ 50

Author(s):

Rene Roy ◽

Sung-Jun Park ◽

Jin-Hwe Kweon ◽

Jin-Ho Choi

Keyword(s):

Mechanical Properties ◽

Honeycomb Core ◽

Constituent Material ◽

Nomex Honeycomb

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Face/Core Debonding Characterization of Foam and Honeycomb Core Sandwich Structures Using Single Cantilever Beam Testing Method

Volume 9: Mechanics of Solids, Structures and Fluids; NDE, Structural Health Monitoring and Prognosis ◽

10.1115/imece2017-72241 ◽

2017 ◽

Author(s):

Mohammad Tauhiduzzaman ◽

Seyed Morteza Sabet ◽

Leif A. Carlsson

Keyword(s):

Fracture Toughness ◽

Cantilever Beam ◽

Failure Modes ◽

Beam Theory ◽

Shear Loading ◽

Least Square ◽

Honeycomb Core ◽

Precracked Specimen ◽

Scb Test

Single Cantilever Beam (SCB) testing was conducted on foam and honeycomb core sandwich specimens to predict the fracture toughness and bonding strength. Adhesion characteristics can also be identified between facesheet and core materials conducting SCB test on precracked specimen. Disbonding under combined tensile and shear loading may involve failure modes such as kinking and cell buckling. Modified Beam Theory (MBT) method specifies required parameters to generate a least square plot based on experimentally determined compliance and disbond length obtained during the SCB test. Interfacial fracture toughness Gc, enumerated by following recommended data reduction methodologies, required to predict minimum Gc to initiate disbond growth. Finally, experimental compliance was compared with elastic foundation stiffness compliance to verify the performance of the test. Good agreement between two compliance solutions validates the accuracy of the SCB test.

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