Papers by Keyword: Syntactic Foam

Abstract: AbstractEpoxy syntactic foams (SF) filled with hollow glass microspheres (HGM) were prepared by simple resin casting method and characterization in this study. The effect of varying the amount of HGM on the specific mechanical and water absorption properties of SF composites were investigated. Five different composition of SF (SFT60-0.5 to SFT60-2.5) were compared with the neat epoxy matrix. The wall thickness of the microballoons differ because of its different percentile size distribution (10^th, 50^th and 90^th), which reflects in its density variation. The results show that the specific tensile and flexural strength increases with an increasing filler (HGM) content. The density of SF filled with HGM reduces with increasing volume fraction of filler content. Scanning electron microscopy was done on the failed samples to examine the fractured surfaces. The water absorption capacity of the SF was also investigated as it relates to the HGM volume fraction variation. All the syntactic foam composition shows a better diffusion coefficient capacity than the neat epoxy resin. This makes it applicable in structural purposes and several marine application products such as Autonomous Ultimately Vehicle (AUV).

Abstract: The production of low-temperature clay lightweight aggregates is pursued eagerly as low energy and cost lightweight aggregate concrete (LAC) building blocks becomes more popular. Clay ceramic hollow spheres (CCHS) with waste glass (WG) additive was developed and studied as aggregate in cement composite. CCHS with diameter ranging in 6/8mm were produced by a sacrificial template technique with subsequent sintering under temperature of 900 °C and different WG content of 0, 5, 7 and 10 wt%. The effect of the sintering temperature and WG content on the physical properties and morphology of the CHS-cement composites were studied by means of optical microscopy and mechanical properties. Obtained composite materials were compared with commercially available lightweight fillers such as foamed glass granules and lightweight expanded clay aggregates (LECA). The results compressive strength of CCHS containing LAC is much higher from 4.8 to 7.1 MPa in comparison with the LECA-cement LAC - 3.5 MPa. Reduction of CCHS open porosity due to higher content of WG (10%) leads to lower absorption of cement paste, as result lower cement consumption, lower bulk density and compression strength. LAC with CCHS proved to be promising construction material due to low-temperature production process (i), widely available raw material (clay) and secondary material (glass cullet) use (ii), reduction of cement paste needed for material production (iii).

Abstract: The thermal properties such the coefficient thermal expansion, α (CTE) of fused borosilicate syntactic foam was determined using dimensional changes of a temperature gradient plot. The CTE was measured and found to be achieved the value lower than the vinyl ester resin matrix when mixing with different weight percentages of the glass microballoon ranging from 2 wt.% to 10 wt.% using a thermomechanical analyzer (TMA). These results showed that it has a strong relationship with the syntactic foam physical properties such density, radius ration,cavity porosity and matrix porosity. Experimental results showed that the CTE decreases when glass microballoons are added into the composites measured at different temperatures ranging from 30 °C to 70 °C. The CTE from the experimental results were also analysed using Turner’s modification model for composites for its suitability for thermal expansion of syntactic foams.

Abstract: The behaviour of aluminium matrix syntactic foams (AMSFs) with homogeneous and graded structures have been studied under quasi-static compression and impact. Particle size of ceramic microspheres and impact velocity had significant effects on the static and impact responses. Smaller microspheres led to higher strength but lower toughness. The compressive yield stress, plateau stress and specific energy absorption of the graded AMSF specimens were approximately the averages of the constituent layers, following the rule of mixture, although the order of the layers had some influence on the compressive behaviour. The syntactic foams were brittle under impact, no matter whether they were brittle or ductile in quasi-static compression. They had higher peak stresses and absorbed more energy in impact than in quasi-static compression. The location of the most brittle layer of the small ceramic microspheres had a significant effect on the impact failure pattern and sequence of the three-layer graded AMSFs.

Abstract: Metal matrix syntactic foams with relativity low density (2.03 g/cm³) were prepared by stir casting method. The syntactic foam is comprised of alumina hollow spheres with a diameter range of 1.0-1.5 mm as reinforcement and ZL111 aluminum alloy as matrix. Calcium particles are used to increase the viscosity of the melt to ensure that low density hollow spheres are immersed in the melt. Microstructure characteristics and quasi-static compressive properties of syntactic foams were studied. The hollow spheres were uniformly distributed in the aluminum matrix, and the interface between them was in continuous contact. Compressive stress-strain curve exhibits three distinct stages of deformation: (i) the linear elastic stage; (ii) the plateau area; (iii) final densification stage. The compression strength and plateau stress are 85 MPa and 75 MPa, respectively. The main reasons for the sample failure are the collapse of hollow spheres and the formation of multiple shear bands.

Abstract: This research focuses on the effect of rejected nitrile butadiene rubber (rNBR) gloves particles reinforced epoxy macrospheres (EM) on the physical properties and compressive stress of syntactic foam. Adding rNBR particles on the surface of macrospheres can increase the energy absorption as a result of improving the compressive properties of syntactic foam. Three types of macrospheres have been produced for the fabrication of syntactic foam, namely EM without rNBR, 1-layer rNBR-EM and 2-layer rNBR-EM. The results showed that increased rNBR particles layer on macrospheres has increased the wall thickness, and reduced the radius ratio of macrospheres as well as increased the density of syntactic foams. The compressive strength and modulus of syntactic foam with 2-rNBR-EM increased compared to the syntactic foams of 1-rNBR-EM and EM without rNBR. In addition, the toughness of the 2-rNBR-EM increased compared to the syntactic foams of 1-rNBR-EM and EM without rNBR.

Abstract: Building protection on our century is very important because of the terrorist attacks. The old buildings in Europe aren’t enough strong again blast loads. Nowadays we know many different explosives and theirs effects of walls and human bodies. The detonation caused blast effect provokes building damage and fragmentation effects. The explosion caused damages, parts of bricks and fragments produce other secondary damage in other buildings and human bodies.It can’t protect the historical and old buildings by new walls and fences because of the cityscape. It needs to find new possibilities to improve the buildings resistance again blast effects. It needs a effectively thin and strong materials to reinforced the buildings walls. The new materials innovated by material science can be good solution for this project. These materials usually composites likes syntactic foams, spherical shells or carbon fields reinforced composites.

Abstract: This paper addresses an innovative syntactic foam produced out of metal powder (Fe), fly ash cenospheres (CS) and clay ceramic syntactic foams composite material (CM). Due to the low density of CS (bulk density - 0.38 g/cm³), the average density of these foams is about 2.6-2.9 g/cm³. It was found that CS undergoes phase transformation during thermal treatment at a temperature of 1200°C. Microstructural observations reveal a uniform distribution of CS and Fe particles in the composite. Compressive strength, and friction coefficient of obtained Fe/CS CM are in the range between 149 - 344 MPa and 0.15 - 1.1, respectively. Dependence of compressive strength on firing temperature is demonstrated exhibiting the maximum at 344 MPa; however, dependence of coefficient of friction on a material properties, obtained at different firing temperature exhibits the minimum value of 0.15 at the firing temperature of 1150 °C. The obtained syntactic form was shown to be a candidate for wear resistant applications.

Abstract: The combinations of polymer resin and glass microballoon are the main materials used to produce syntactic foams. Syntactic foam is a lightweight material that has good mechanical properties and is commonly used as a component for structural materials in civil construction, aerospace and marine applications. Hence, it should have suitable mechanical properties, particularly good compression behaviour. In the present study, the results obtained from compression tests are compressive strength, elastic modulus and specific compression that decrease when increasing of glass microballoon contents (2.0 wt.%, 4.0 wt.%, 6.0 wt.%, 8.0 wt.% and 10.0 wt.%) and also neat resin. The highest strength value for compression testing is owned by 2.0 wt.% which is 88.9 MPa, while the lowest strength is 43 MPa that belongs to 10.0 wt.% of glass microballoon. This shows that the density and weight percentage of glass microballoon in these syntactic foams affect compression properties. Therefore, a further study should be conducted, which includes the effect of compressive failure mechanism.

Abstract: The study aimed to investigate the compression behaviors of syntactic foam reinforced by warp knitted spacer fabric (SF-WKSF). Two kinds of SF-WKSF samples were prepared with warp knitted spacer fabric (WKSF) of different surface layer structures. The compression tests were carried out by MTS 810 material test system and the compression properties of SF-WKSF were analyzed based on its compressive stress–strain curves and modulus values obtained from test results. It is indicated that the surface layer structure of WKSF has significant effects on the compression performance of SF-WKSF, the SF-WKSF made with denser surface layer structure shows higher compressive modulus and yield strength compared to neat syntactic foam (NSF).