Non-stochastic lattice structures for novel filter applications fabricated via additive manufacturing

Non-stochastic lattice structures are widely used in a variety of applications such as biomedical implants and heat exchangers. However, the utilisation of these structures for filtration applications is rather new. Additive manufacturing techniques such as selective laser melting allows lattice structures to be bespoke depending on the type of filter and its intended function. This study considers the flow characteristics and structural strength of a disc filter with a layer of repeated 1.8 mm lattice unit cell as the filter mesh. Computational fluid dynamics simulation is used to analyse the pressure and flow velocity across the filter, while finite element analysis is utilised to analyse the structural characteristics of the lattice mesh under fluid load. The results show a minimal decrease in pressure and small increases in velocity, with the mesh capable of withstanding higher loads. The ultimate failure load of the structure is also determined. These findings indicate that more layers of lattice structures could be used as filter mesh and the flexibility of AM allows the filter properties to be tailored as required for a given application

Powder removal from Ti-6Al-4V cellular structures fabricated via electron beam melting

Direct metal fabrication systems like electron beam melting (EBM) and direct metal laser sintering (also called selective laser melting) are gaining popularity. One reason is the design and fabrication freedom that these technologies offer over traditional processes. One specific feature that is of interest is mesh or lattice structures that can be produced using these powder-bed systems. One issue with the EBM process is that the powder trapped within the structure during the fabrication process is sintered and can be hard to remove as the mesh density increases. This is usually not an issue for the laser-based systems since most of them work at a low temperature and the sintering of the powder is less of an issue. Within the scope of this project, a chemical etching process was evaluated for sintered powder removal using three different cellular structures with varying mesh densities. All meshes were fabricated via EBM using Ti6Al4V Footnote Information powder. The results are promising, but the larger the structures, the more difficult it is to completely remove the sintered powder without affecting the integrity of the mesh structure

Pressure Drop and Velocity Simulations in Non-Stochastic Structures - Filters Fabricated by Additive Manufacturing

This research utilises additive manufacturing technology to fabricate filter mesh designed with non-stochastic lattice structures. Disc filters with 1-layer, 2-layer and 3-layer thicknesses of repeated 1.8 mm lattice unit cell as the filter mesh are modelled in SolidWorks. Computational Fluid Dynamic (CFD) simulation using ANSYS CFX is performed at eight different flow rates (250-390 lit/min) and the results (pressure drop and velocity) are analysed. Simulations are also done for perforated plates with circular-shaped and square-shaped holes with the same aperture size and filter cut point for benchmarking purposes. The outcomes indicate that the pressure drop of the lattice filters is noticeably lower than the perforated plates. These findings show that several layers of lattice structure could be stacked together as filter mesh to increase filtration efficiency with minimal pressure drop and to create a more tortuous path for the fluid

Analysis of unimorph piezoceramic patches on damped square shaped plate

Active damping using piezoelectric element is one of the effective techniques to counter vibration problems. A 3D finite-element model is developed as part of investigation for damping control. The piezoelectric patches are surface bonded on quadrilateral thin plate and supported with spring damper elements. The main goal of this paper is to investigate mechanical characteristics of piezoceramic array on membrane and the effect of force excitation using small motor and electric excitation on the system. The system setup produced small vibration displacement and does not displace the plate beyond elastic strain region. The results show the linear behavior of piezoceramic and the correlation between electric excitation, motor vibration and displacement at the centre of the plate at different frequency range. The mode shapes and natural frequencies at low frequency spectrum are also presented. Therefore, the results can be used as reference to develop damping system with aid of piezoelectric patches

E-RECYCLING SYSTEM MODEL AND ITS APPLICATIONS TO PLASTIC, PAPER AND DISC

Lately, Malaysians tend to generate wastes at an alarming rate, for instance; discs, paper and plastics. Abreast of that, the conventional recycling systems that have been constructed in Malaysia typically are not widely marketed and are lacking of practical applications. This study comes with an intention of concentrating on the improvement of this particular conventional renewed Erecycling system model that includes database system (generally known as Merit Point Incentive (MPI) system) and CAD model. Due to its applicability, the model is examined by Linear Static and Fatigue analyses. The comparison (cost efficiency) amongst the conventional and E- recycling systems are shown throughout this study

A short review on polyaniline (PANI) based nanocomposites for various applications: enhancing the electrical conductivity

This short review has summarized the significance of polyaniline (PANI) advanced polymer that focusing into their modification strategy, electrical conductivity and various potential applications. PANI is one type of conductive polymer that was synthesized by oxidative aniline polymerization with varied concentration of acid dopant. In recent year, many researches has been conducted specifically to enhance the electrical conductivity of PANI. There have been numbers of studies involving PANI that specially reported the electrical conductivity could be improved through proper dopant (acid) selection and robust composite strategy. The PANI based nanocomposite shows higher electrical conductivity by integrating it with nanofiller due to the filler-matrix interface contact. Therefore, by modifying the PANI properties, it could be benefited for various potential application in the future

Electrical Conductivity and Antenna Properties of Polyaniline filled GNPs Nanocomposites.

This study was conducted to investigate the potential of utilizing conductive polymer nanocomposite for flexible type antenna application. The polyaniline (PANI) filled with graphene nanoplatelets (GNPs) nanocomposites were synthesized by an oxidative aniline polymerization in an acidic medium. The PANI/GNPs nanocomposites were then characterized by using various spectroscopy and imaging tools. It was found that the strong interaction between PANI macromolecules and GNPs flakes is caused by the strong π-π conjugation between them, as validated by an increase of Id/Ig ratio of PANI/GNPs nanocomposites. As a result, it established a three-fold improvement for the electrical conductivity of PANI/GNPs nanocomposites, due to the larger amount of charge carrier transport at higher GNPs nanofiller loadings (1.00 wt.%). Later, the PANI/GNPs nanocomposites powder was applied to the cotton fabric by integrating it with a rubber paint slurry. Electrical conductivity, antenna gain, return loss, and radiation pattern of the antenna were reported. It was found that PANI/GNPs flexible textile antenna possessed a constant gain of 4.1809 dB, return loss at -13.154 dB, and radiation pattern which operated at 10.36 GHz for 100% improvement of electrical conductivity, in comparison with unfilled PANI. From these findings, it can be said that the development of wearable textile antenna utilizing PANI/GNPs nanocomposites on the cotton fabric as flexible radiation patch, has great potential for wireless communication purposes

Effect Of Different Cooking Temperature And Alkalinity On Mechanical And Morphological Properties Of Composite Sheet From Durian Shell

Temperature and alkalinity are the critical factors that contribute to the successful of soda pulping. These factors influence the length size and interfibre bonding of the fibre. In this paper, durian (Durio zibethinus Murray) shell composite sheet were prepared by conducting chemical pulping through soda method to study the effect of different pulping temperature and % of NaOH on the mechanical and morphological characteristics of durian shell composite sheet. Six sets of composite sheet were produced from six sets of pulping. The pulping processes were conducted at 140, 160 and 170°C with 17, 19 and 21% of active alkali. The mechanical properties of the durian shell composite sheet were analyzed through few standard TAPPI analyses which are tensile, tear, burst, folding endurance and paper bulk thickness. The results show that the highest reading of paper bulk thickness, tensile, tear and burst index, and also folding endurance were achieved at the pulping condition of 170°C with 21% of NaOH with the value of 1.3366 g/cm3, 54.151 NM/g, 6.648 m.Nm2/g, 2.517 k.Pam2/g and 170 no. of fold, respectively. Scanning electron microscopic analysis showed that morphological changes took place depending on the size and arrangement of the fibres in the composites sheet

Modeling of a jig sampling and its application in disc cutter tools

The operations of preparing the deform sample and round bar mainly consist of the calculation of the bar's unit weight. The Sampling process is conducted through the two cutting flows such as in line production and disc. The problems are then occurred in the second flow (in disc) in performing the cutting process on a certain length. Modeling of the jig sampling is used to solve this problem and also fully discussed throughout this paper

Pressure drop and velocity simulations in non-stochastic lattice structure for filter applications fabricated using additive manufacturing

This research utilises additive manufacturing technology to fabricate filter mesh designed with non-stochastic lattice structures. Disc filters with 1-layer, 2-layer and 3-layer thicknesses of repeated 1.8 mm lattice unit cell as the filter mesh are modelled in SolidWorks. Computational Fluid Dynamic (CFD) simulation using ANSYS CFX is performed at eight different flow rates (250 lit/min, 270 lit/min, 290 lit/min, 310 lit/min, 330 lit/min, 350 lit/min, 370 lit/min and 390 lit/min) and the results (pressure drop and velocity) are analysed. Simulations are also done for perforated plates with circular-shaped and square-shaped holes with the same aperture size for benchmarking purposes. The outcomes indicate that the pressure drop of the lattice filters is noticeably lower than the perforated plates’. These findings show that several layers of lattice structure could be stacked together as filter mesh to increase filtration efficiency with minimal pressure drop and to create a more tortuous path for the fluid