Effect of manufacture induced interfaces on the tensile properties of 3D printed polyamide and short carbon fibre reinforced polyamide composites

This study aims to elucidate the structure–property–process relationship of 3D printed polyamide and short carbon fibre-reinforced polyamide composites. The macroscopic properties (tensile modulus) of the 3D printed samples are quantitatively correlated to the printing process-induced intrinsic microstructure with multiple interfaces. The samples were printed with different layer thicknesses (0.1, 0.125 and 0.2 mm) to obtain the varied number of interface densities (number of interfaces per unit sample thickness). The result shows that the printed short carbon fibre-reinforced polyamide composites had inferior partially bonded interfaces compared to the printed polyamide, and consequently exhibited interface-dependent elastic performance. The tensile modulus of 3 mm thick composites decreased up to 18% as a function of interface density, whilst the other influencing aspects including porosity, crystallinity and fibre volume fraction (9%) were the same. Injection moulding was also employed to fabricate samples without induced interfaces, and their tensile properties were used as a benchmark. Predictions based on the shear-lag model were in close agreement (<5%) with the experimental data for the injection-moulded composites, whereas the tensile modulus of the printed composites was up to 38% lower than the predicted modulus due to the partial bonded interfaces

Parametric Optimization of Lactic Acid Extraction from Aqueous Solution in a Mixed Flow Reactor using Emulsion Liquid Membrane by Response Surface Methodology

A statistical programme using Box-Behnken design, which applies a response optimization algorithm, was used to calculate and optimize simultaneously the lactic acid extraction by emulsion liquid membrane (ELM) in a mixed flow reactor. A 3-level Box-Behnken design with seven variables i.e. lactic acid concentration, internal reagent concentration, Alamine 336 fraction in oleyl alcohol, stirring speed, fraction of acceptor phase containing internal reagent in emulsion feed: emulsion ratio and residence time was used to identify a significant correlation between the effect of these variables on lactic acid extraction from aqueous phase since the conventional practice of single factor optimization by maintaining other factors at an unspecified constant level does not depict the combined effect of all the factors involved. The experimental values were found to be in good agreement with predicted values. The analysis of the variance (ANOVA) shows that all the extraction process parameters significantly affect the performance and also shows that there are some interactions between the extraction parameters. The contribution of feed: emulsion ratio and stirring speed on extraction efficiency was more than other factors and the fraction of acceptor phase in emulsion has minimum contribution. The optimum value of the process quantities for the maximization of extraction of lactic acid from aqueous phase using ELM in MFR by the application of Box-Behnken design has been found. The recommended optimal conditions have been verified by conducting confirmation experiments. It can be concluded that the Box-Behnken experimental design provides a suitable means of optimizing and testing the robustness of lactic acid extraction in a MFR using emulsion liquid membrane and 100 % lactic acid extraction in MFR using ELM from aqueous feed can be achieved in few minutes within the specified range of independent process parameters

Parametric Optimization of Lactic Acid Extraction from Aqueous Solution in a Mixed Flow Reactor using Emulsion Liquid Membrane by Response Surface Methodology

A statistical programme using Box-Behnken design, which applies a response optimization algorithm, was used to calculate and optimize simultaneously the lactic acid extraction by emulsion liquid membrane (ELM) in a mixed flow reactor. A 3-level Box-Behnken design with seven variables i.e. lactic acid concentration, internal reagent concentration, Alamine 336 fraction in oleyl alcohol, stirring speed, fraction of acceptor phase containing internal reagent in emulsion feed: emulsion ratio and residence time was used to identify a significant correlation between the effect of these variables on lactic acid extraction from aqueous phase since the conventional practice of single factor optimization by maintaining other factors at an unspecified constant level does not depict the combined effect of all the factors involved. The experimental values were found to be in good agreement with predicted values. The analysis of the variance (ANOVA) shows that all the extraction process parameters significantly affect the performance and also shows that there are some interactions between the extraction parameters. The contribution of feed: emulsion ratio and stirring speed on extraction efficiency was more than other factors and the fraction of acceptor phase in emulsion has minimum contribution. The optimum value of the process quantities for the maximization of extraction of lactic acid from aqueous phase using ELM in MFR by the application of Box-Behnken design has been found. The recommended optimal conditions have been verified by conducting confirmation experiments. It can be concluded that the Box-Behnken experimental design provides a suitable means of optimizing and testing the robustness of lactic acid extraction in a MFR using emulsion liquid membrane and 100 % lactic acid extraction in MFR using ELM from aqueous feed can be achieved in few minutes within the specified range of independent process parameters

A CME-Producing Solar Eruption from the Interior of a Twisted, Emerging Bipole

In a negative-polarity coronal hole, magnetic flux emergence, seen by the Solar Dynamics Observatory's (SDO) Helioseismic Magnetic Imager (HMI), begins at approximately 19:00 UT on March 3, 2016. The emerged magnetic field produced sunspots with penumbrae by 3:00 UT on March 4, which are a part of NOAA 12514. The emerging magnetic field is largely bipolar with the opposite-polarity fluxes spreading apart overall, but there is simultaneously some convergence and cancellation of opposite-polarity flux at the polarity inversion line (PIL) inside the emerging bipole. The emerging bipole shows obvious overall left-handed shear and/or twist in its magnetic field and corresponding clockwise rotation of the two poles of the bipole about each other as the bipole emerges. The eruption comes from inside the emerging bipole and blows it open to produce a CME observed by SOHO/LASCO. That eruption is preceded by flux cancellation at the emerging bipole's interior PIL, cancellation that plausibly builds a sheared and twisted flux rope above the interior PIL and fnally triggers the blow-out eruption of the flux rope via photospheric-convection-driven, slow tether-cutting reconnection of the legs of the sheared core field, low above the interior PIL, as proposed by van Ballegooijen and Martens (1989, ApJ, 343, 971) and Moore and Roumeliotis (1992, in Eruptive Solar Flares, ed. Z. Svestka, B.V. Jackson, and M.E. Machado [Berlin:Springer], 69). The production of this eruption is a (perhaps rare) counterexample to solar eruptions that result from external collisional shearing between opposite polarities from two distinct emerging and/or emerged bipoles (Chintzoglou et al., 2019, ApJ, 871:67)

An Optimization Based Design Framework for Multi-Functional 3D Printing

This work investigates design analysis and optimization methods for the integration of active internal systems into a component for manufacture using multi-material 3D printing processes. This enables efficient design of optimal multifunctional components that exploit the design freedoms of additive manufacturing (AM). The main contributions of this paper are in two areas: 1) the automated placement and routing of electrical systems within the component volume and, 2) the accommodation of the effect of this system integration on the structural response of the part through structural topology optimization (TO). A novel voxel modeling approach was used to facilitate design flexibility and to allow direct mapping to the 3D printer jetting nozzles.Mechanical Engineerin

Design Optimization Strategy for Multifunctional 3D Printing

An optimization based design methodology for the additive manufacture of multifunctional parts (for example, a structure with embedded electronic/electrical systems and associated conductive paths) is presented. This work introduces a coupled optimization strategy where Topology Optimization (TO) is combined with an automated placement and routing approach that enables determination of an efficient internal system configuration. This permits the effect of the incorporation of the internal system on the structural response of the part to be taken into account and therefore enables the overall optimization of the structure-system unit. An example test case is included in the paper to evaluate the optimization strategy and demonstrate the methods effectiveness. The capability of this method allows the exploitation of the manufacturing capability under development within the Additive Manufacturing (AM) community to produce 3D internal systems within complex structures.Mechanical Engineerin

Predicting Temperature Field for Metal Additive Manufacturing using PINN

Machine-learning-based methods are gaining traction as an alternative to numerical methods in many engineering applications. Physics-informed neural network (PINN), a self-supervised method, is particularly attractive with its unique capability of guiding the training with physical laws written in the forms of partial differential equations. Thermomechanical simulation for additive manufacturing (AM), a multi-scale, multi-physics problem could potentially benefit from the use of PINN, as demonstrated in some successful attempts in the literature. In this work, PINN is applied to different metal AM processes and several challenges that limit the robustness of PINN are observed. This paper aims to provide a summary of the observations and a preliminary attempt to account for such observations in order to pave the path for future work that aims to unleash the full promise of PINN in AM-related applications.Mechanical Engineerin

Mechanical performance of additively manufactured fiber-reinforced functionally graded lattices

Latticing has become a common design practice in additive manufacturing (AM) and represents a key lightweighting strategy to date. Functional graded lattices (FGLs) have recently gained immense traction in the AM community, offering a unique way of tailoring the structural performance. This paper constitutes the first ever investigation on the combination of graded strut- and surface-based lattices with fiber-reinforced AM to further increase the performance-to-weight ratio. The energy absorption behavior of cubic lattice specimens composed of body-centered cubic and Schwarz-P unit cells with different severities of grading but the same mass, considered for uniaxial compression testing and printed by fused deposition modelling of short fiber-reinforced nylon, were investigated. The results elucidate that grading affects the energy absorption capability and deformation behavior of these lattice types differently. These findings can provide engineers with valuable insight into the properties of FGLs, aiding targeted rather than expertise-driven utilization of lattices in design for AM