Mechanical and Acoustic Performance of Compression Molded Open Cell Polypropylene Foams

2008 ◽  
Author(s):  
Joe D. McRae ◽  
Hani E. Naguib ◽  
Noureddine Atalla
Keyword(s):  
Relative Density ◽  
Mechanical Testing ◽  
Cell Size ◽  
Cell Density ◽  
Mechanical Performance ◽  
Acoustic Absorption ◽  
Mass Ratio ◽  
Open Cell ◽  
Acoustic Performance ◽  
Particulate Leaching

The mechanical and acoustic performance of open cell polypropylene (PP) foam has been studied in this paper. The particulate leaching method was used to fabricate the open cell PP samples. Foaming parameters such as salt size and salt/polymer mass ratio were controlled to produce samples with different open cell morphologies. The study analyzes the effects cell size, cell density, and relative density have on mechanical and acoustic performance. Mechanical testing was conducted to quantify stiffness and strength of the open cell PP foams. Optimal cellular morphologies for acoustic absorption and mechanical performance were identified.

Development of Bio-Based Foams With Improved Acoustic and Mechanical Performance

2012 ◽  
Author(s):  
Shahrzad Ghaffari Mosanenzadeh ◽  
Hani E. Naguib ◽  
Chul B. Park ◽  
Noureddine Atalla
Keyword(s):  
Mechanical Characteristics ◽  
Mechanical Performance ◽  
Water Soluble ◽  
Huge Amount ◽  
Open Cell ◽  
Acoustic Performance ◽  
Foam Morphology ◽  
Open Cell Foams ◽  
Weak Structure ◽  
Highly Porous

Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the non-recyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding. Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved. One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyalkanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology. Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries.

Effect of Cell Size on the Dynamic Compressive Properties of Aluminum Alloy Foams

2007 ◽  
Vol 124-126 ◽  
pp. 1317-1320 ◽  
Author(s):  
Zhi Hua Wang ◽  
Hong Wei Ma ◽  
Long Mao Zhao ◽  
Gui Tong Yang
Keyword(s):  
Aluminum Alloy ◽  
Yield Strength ◽  
Strain Rate ◽  
Relative Density ◽  
Cell Size ◽  
Cell Morphology ◽  
Compressive Properties ◽  
Aluminum Foams ◽  
Open Cell ◽  
Mechanical Responses

The static and dynamic compressive behaviors of open-cell aluminum alloy foams with virtually the same relative density of 0.4 were investigated. The foams have different cell sizes (0.5mm, 1.5mm, 2.5mm) but similar cell morphology and microstructure. The yield strength of these foams was characterized as a function of strain rate and cell morphology. The experimental results indicated that the mechanical responses of foams are sensitive to strain rate, and dependent of the cell size. The present results are compared in details with recent findings obtained from the aluminum foams.

scholarly journals Mechanical Properties of an Igneous Aggregate-Modified Hydraulic Concrete

2001 ◽  
Vol 10 (2) ◽  
pp. 096369350101000
Author(s):  
E. Alonso ◽  
L. Martvnez-Gomez ◽  
W. Martvnez ◽  
L. Villaseρor ◽  
V.M. Castapo
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Mechanical Testing ◽  
Mechanical Performance ◽  
Central Mexico ◽  
Natural Sources ◽  
Hydraulic Concrete ◽  
West Central ◽  
Careful Control

Portland cement concretes were prepared by adding different igneous materials from west central Mexico. The results of the mechanical testing of these materials show the feasibility of employing igneous minerals to produce concretes and mortars, provided a careful control of granulometry and the geochemistry involved is attained. The mechanical performance, as well as the workability of the slurries can be managed by the convenient use of commercial additives (i.e. water reducers and aging accelerators). These results open the attractive possibility of expanding the natural sources of concrete-forming elements.

scholarly journals New Dental Implant with 3D Shock Absorbers and Tooth-Like Mobility—Prototype Development, Finite Element Analysis (FEA), and Mechanical Testing

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3444
Author(s):  
Avram Manea ◽  
Grigore Baciut ◽  
Mihaela Baciut ◽  
Dumitru Pop ◽  
Dan Sorin Comsa ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mechanical Testing ◽  
Alveolar Bone ◽  
Mechanical Performance ◽  
Implant Design ◽  
Element Analysis ◽  
Prototype Development ◽  
Second Stage ◽  
Testing Protocol

Background: Once inserted and osseointegrated, dental implants become ankylosed, which makes them immobile with respect to the alveolar bone. The present paper describes the development of a new and original implant design which replicates the 3D physiological mobility of natural teeth. The first phase of the test followed the resistance of the implant to mechanical stress as well as the behavior of the surrounding bone. Modifications to the design were made after the first set of results. In the second stage, mechanical tests in conjunction with finite element analysis were performed to test the improved implant design. Methods: In order to test the new concept, 6 titanium alloy (Ti6Al4V) implants were produced (milling). The implants were fitted into the dynamic testing device. The initial mobility was measured for each implant as well as their mobility after several test cycles. In the second stage, 10 implants with the modified design were produced. The testing protocol included mechanical testing and finite element analysis. Results: The initial testing protocol was applied almost entirely successfully. Premature fracturing of some implants and fitting blocks occurred and the testing protocol was readjusted. The issues in the initial test helped design the final testing protocol and the new implants with improved mechanical performance. Conclusion: The new prototype proved the efficiency of the concept. The initial tests pointed out the need for design improvement and the following tests validated the concept.

scholarly journals Gas Mixing and Final Mixture Composition Control in Simple Geometry Micro-mixers via DSMC Analysis

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 178 ◽  
Author(s):  
Stavros Meskos ◽  
Stefan Stefanov ◽  
Dimitris Valougeorgis
Keyword(s):  
Relative Density ◽  
Molecular Mass ◽  
Hard Sphere ◽  
Density Difference ◽  
Mixture Composition ◽  
Minor Effect ◽  
Mixing Length ◽  
Mass Ratio ◽  
Gas Mixing ◽  
A Minor

The mixing process of two pressure driven steady-state rarefied gas streams flowing between two parallel plates was investigated via DSMC (Direct Simulation Monte Carlo) for different combinations of gases. The distance from the inlet, where the associated relative density difference of each species is minimized and the associated mixture homogeneity is optimized, is the so-called mixing length. In general, gas mixing progressed very rapidly. The type of gas surface interaction was clearly the most important parameter affecting gas mixing. As the reflection became more specular, the mixing length significantly increased. The mixing lengths of the HS (hard sphere) and VHS (variable hard sphere) collision models were higher than those of the VSS (variable soft sphere) model, while the corresponding relative density differences were negligible. In addition, the molecular mass ratio of the two components had a minor effect on the mixing length and a more important effect on the relative density difference. The mixture became less homogenous as the molecular mass ratio reduced. Finally, varying the channel length and/or the wall temperature had a minor effect. Furthermore, it was proposed to control the output mixture composition by adding in the mixing zone, the so-called splitter, separating the downstream flow into two outlet mainstreams. Based on intensive simulation data with the splitter, simple approximate expressions were derived, capable of providing, once the desired outlet mixture composition was specified, the correct position of the splitter, without performing time consuming simulations. The mixing analysis performed and the proposed approach for controlling gas mixing may support corresponding experimental work, as well as the design of gas micro-mixers.

Tuning Porosity and Mechanical Properties of Ti6Al4V Alloy Additively Manufactured by SLM

2020 ◽  
Vol 865 ◽  
pp. 1-5
Author(s):  
Michaela Roudnicka ◽  
Jiri Bigas ◽  
Dalibor Vojtech
Keyword(s):  
Mechanical Properties ◽  
Energy Density ◽  
Relative Density ◽  
Process Optimization ◽  
Mechanical Performance ◽  
Microstructural Characterization ◽  
Scanning Speed ◽  
Ti6al4v Alloy ◽  
Machine Material ◽  
Specific Product

Selective laser melting (SLM), as the main representative of additive manufacturing technologies, has a high variability of process parameters setting, which provides wide possibilities in tuning porosity and mechanical properties of final parts. To ensure a high relative density of SLM parts, thorough process optimization is required. Efforts so far developed in this research area suggest that the optimization is desirable for each machine, material and suitably even for a specific product. As even the adjustment of a specific machine may affect the resulting part quality, we carried out an initial process optimization for a specific SLM machine applied to the processing of Ti6Al4V alloy. We studied a range of energy density values between 40-400 J/mm3 by changing scanning speed and hatching distance. The results of this initial optimization demonstrated how porosity and mechanical properties can be varied widely with different parameter settings, suggested a processing window for reaching the highest relative density and revealed that changing the energy density might be also associated with microstructural changes influencing the mechanical performance of a final part. Therefore, our follow-up study will focus on detail microstructural characterization.

Processing of Polymer-Derived Microcellular Ceramics Containing Reactive Fillers

2007 ◽  
Vol 534-536 ◽  
pp. 989-992 ◽  
Author(s):  
Young Wook Kim ◽  
Doo Hee Jang ◽  
Jung Hye Eom ◽  
In Hyuck Song ◽  
Hai Doo Kim
Keyword(s):  
Silicon Carbide ◽  
Cell Size ◽  
Cell Density ◽  
Reaction Method ◽  
Novel Processing ◽  
Cell Densities ◽  
Cordierite Ceramics ◽  
Processing Techniques ◽  
Study Offer

Processing techniques for producing microcellular silicon carbide, mullite, and cordierite ceramics with cell densities greater than 108 cells/cm3 and cells smaller than 30 μm have been developed by a reaction method that incorporates a polysiloxane and reactive fillers. The techniques developed in this study offer substantial flexibility for producing microcellular ceramics whereby cell size, cell density, degree of interconnectivity, composition, and porosity can all be effectively controlled. It is demonstrated that the adjustment of filler composition enables the possibility of tailoring the composition and properties of the microcellular ceramics. The present results suggest that the proposed novel processing techniques are suitable for the manufacture of microcellular ceramics with high morphological uniformity.

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