Correlation between infill percentages, layer width, and mechanical properties in fused deposition modelling of poly-lactic acid 3D printing

The field of additive manufacturing (AM) has seen a transformation in the production of intricate and complex parts for various applications. Fused Deposition Modelling (FDM), among AM techniques, has garnered significant attention, particularly in fields like fibre-reinforced composites (FRC). In this study, the world of FDM-printed Polylactic Acid (PLA) components is explored, with a focus on how mechanical properties are influenced by infill percentages and layer widths. Through the utilisation of Response Surface Methodology (RSM), the optimisation of FDM-PLA 3D printing for a wide range of biomaterial applications is achieved, along with the unveiling of the potential for remarkable improvements in mechanical performance. Notably, a remarkable 91% reduction in surface roughness for PLA composites was achieved, accompanied by an impressive 25.6% and 34.1% enhancement in the tensile strength and Young’s modulus of fibre-reinforced PLA composites, respectively. This work, positioned at the crossroads of FDM, lays the groundwork for substantial advancements in the realm of additive manufacturing.Peer ReviewedPostprint (published version

Finite element analysis of the effect of shape memory alloy on the stress distribution and contact pressure in total knee replacement

As a step towards developing a biomaterial for femoral component of total knee replacement, the goals of this study were to introduce NiTi shape memory alloy as a promising material for orthopedic implant and to evaluate the effect of different material properties on contact behavior of the joint and stress distribution of the femoral bone using finite element method. Two separate finite element analyses were performed; one with rigid bones and the other with deformable femur, at 0 degree of flexion angle under static loading condition. The results showed no difference between the various materials with regards to the peak contact pressure but considerable difference with regards to the Von Mises stresses. The results also demonstrated that stress values closer to the natural femur were obtained for NiTi implant compared with other metals. Hence, this finite element analysis showed that NiTi shape memory alloy can reduce the stress shielding effect on the femoral bone

Using design of experiments methods for assessing peak contact pressure to material properties of soft tissue in human knee

Contact pressure in the knee joint is a key element in the mechanisms of knee pain and osteoarthritis. Assessing the contact pressure in tibiofemoral joint is a challenging mechanical problem due to uncertainty in material properties. In this study, a sensitivity analysis of tibiofemoral peak contact pressure to the material properties of the soft tissue was carried out through fractional factorial and Box-Behnken designs. The cartilage was modeled as linear elastic material, and in addition to its elastic modulus, interaction effects of soft tissue material properties were added compared to previous research. The results indicated that elastic modulus of the cartilage is the most effective factor. Interaction effects of axial/radial modulus with elastic modulus of cartilage, circumferential and axial/radial moduli of meniscus were other influential factors. Furthermore this study showed how design of experiment methods can help designers to reduce the number of finite element analyses and to better interpret the results

Contrasting the mechanical and metallurgical properties of laser welded and gas tungsten arc welded S500MC steel

S500MC steel is a grade of high-strength low-alloy steel (HSLA) which is widely used in the automotive industry and for agricultural machinery and equipment. Considering properties of this alloy, selection of the welding process and parameters becomes essential to ensure that HSLA assemblies meet specific service requirements. In this work, mechanical and metallurgical properties of S500MC steel produced by autogenous laser beam welding (LBW) and automatic gas tungsten arc welding (GTAW) were compared. Tensile testing, metallography, hardness testing, and fractographic analysis were performed on the welded specimens, revealing that the heat input by these welding processes caused significant microstructural changes within the joints. In LBW samples, the heat input about 10 times lower than that in GTAW produced a finer microstructure, narrower fusion zone width, and smaller heat-affected zone. All fractures of the GTAW specimens occurred in the base metal, while all fractures of the LBW specimens occurred in the weld zone, both regardless of the heat input. GTAW joints exhibited higher mechanical properties (even higher than those obtained in the base metal) as compared to LBW joints

The Synergic Effects of FDM 3D Printing Parameters on Mechanical Behaviors of Bronze Poly Lactic Acid Composites

In this paper, the influence of layer thickness (LT), infill percentage (IP), and extruder temperature (ET) on the maximum failure load, thickness, and build time of bronze polylactic acid (Br-PLA) composites 3D printed by the fused deposition modeling (FDM) was investigated via an optimization method. PLA is a thermoplastic aliphatic polyester obtained from renewable sources, such as fermented plant starch, especially made by corn starch. The design of experiment (DOE) approach was used for optimization parameters, and 3D printings were optimized according to the applied statistical analyses to reach the best features. The maximum value of failure load and minimum value of the build time were considered as optimization criteria. Analysis of variance results identified the layer thickness as the main controlled variable for all responses. Optimum solutions were examined by experimental preparation to assess the efficiency of the optimization method. There was a superb compromise among experimental outcomes and predictions of the response surface method, confirming the reliability of predictive models. The optimum setting for fulfilling the first criterion could result in a sample with more than 1021 N maximum failure load. Finally, a comparison of maximum failure from PLA with Br-PLA was studied

Examination of bio convection with nanoparticles containing microorganisms under the influence of magnetism fields on vertical sheets by five-order Runge-Kutta method

In this paper, we analyzed vertical bio convection in nanofluids containing microorganisms. The novelty of this article is the numerical and analytical investigation of magnetic flow, radiation heat transfer, and viscous dissipation on bio convective fluid flow using the Five-order Runge-Kutta technique. Utilizing similitude parameters, determined ODE (ordinary differential equation) equations from partial differential equations for continuity, momentum, energy, and nanofluid concentration. Five-order Runge-Kutta was then used to solve the equations. The results show that it has a more significant influence on and then and. In addition, it exerts a force on neighboring particles, which causes them to shift from a hot zone to a great region. The density of microorganisms inside a part rises as it grows; when Le rises and Ha remains the same, x(ξ) falls, and When Ha rises, and Le remains the same, x(ξ) fall

Contrasting the mechanical and metallurgical properties of laser welded and gas tungsten arc welded S500MC steel

S500MC steel is a grade of high-strength low-alloy steel (HSLA) which is widely used in the automotive industry and for agricultural machinery and equipment. Considering properties of this alloy, selection of the welding process and parameters become essential to ensure that HSLA assemblies meet specific service requirements. In this work, mechanical and metallurgical properties of S500MC steel produced by autogenous laser beam welding (LBW) and automatic gas tungsten arc welding (GTAW) were compared. Tensile testing, metallography, hardness testing, and fractographic analysis were performed on the welded specimens, revealing that the heat input by these welding processes caused significant microstructural changes within the joints. In LBW samples, the heat input about 10-times lower than in GTAW produced a finer microstructure, narrower fusion zone width and smaller heat affected zone. All fractures of the GTAW specimens occurred in the base metal, while all fractures of the LBW specimens occurred in the weld zone, both regardless of the heat input. GTAW joints exhibited higher mechanical properties (even higher than those obtained in the base metal) as compared to LBW joints

Optimizing fluid parameters of heat transfer and velocity of aluminum oxide nanoparticles and SWCNT passing through blades using RSM statistical method

This paper explores how the temperature and velocity change in a specific direction and the rotational velocity when nanofluids flow through triangular, rectangular, and chamfer baffles. The novelty of this article is to study and investigate the thermal and fluidic parameters of the velocity gradient and heat transferred between aluminum oxide and SWCNT nanofluids on the tensile surface. This study aims to increase the heat transfer coefficient by installing blades with different shapes. The Finite Element Method is chosen to solve the main equations. This paper utilized the RSM method to optimize the velocity of nanofluid and heat transfer as it passes through the stretching sheet. The main goal of this study mentioned in the article is to explore the impact of various vane shapes installed on the outer surface of a stretched sheet. To summarize, after analyzing the flow of SWCNT and Al2O3 nanofluids on various baffles and blades, it was found that the temperature of SWCNT nanofluid around the baffles was higher compared to the temperature of Al2O3 nanofluids. According to the results from the graphs of how fast something is turning and the factors that transfer heat in the software called Design-Expert, the best improvement happened when the velocity and temperature of the small particles in the liquid were at u = 1.12, and T = 20.18 and the turning velocity was N = 137.29

Entropy analysis and mixed convection of nanofluid flow in a pillow plate heat exchanger in the presence of porous medium

A pillow plate heat exchanger (PPHE) is one of the types of heat exchangers that haven't received the attention they deserve despite their high efficiency and operational capability. A unique feature of PPHEs is their pillow-shaped structure, which is achieved through hydroforming. In light of this, scholars have been interested in analyzing and optimizing the thermo-hydraulic properties of PPHEs. In this study, the interior of the PPHE was occupied with a permeable substance with a high porosity percentage (0.9034 ≤ ɛ ≤ 0.9586 and 0.00015 ≤ dp ≤ 0.00065) and saturated with Ag-water (0 ≤ϕ ≤ 0.06) nanofluid, which has a profound influence on the heat transfer rate of PPHEs. In order to analyze the determinants affecting the heat transfer rate of PPHEs under these conditions, the governing equations were solved using the finite volume method and also the Brinkman-Forchheimer-extended Darcy equation. According to the results, heat transfer is enhanced in PPHE when using a permeable medium with high porosity and a small pore size. That is, PPHEs transfer heat more efficiently when they are placed in a denser porous medium because heat conduction is boosted. Moreover, due to the increased thermal conductivity of the nanoparticles, the application of nanoparticles to the base fluid also enhanced heat transfer and Nusselt number. However, decreases in friction factor and entropy generation were observed with increasing porosity, pore size, and Darcy number, due to reduced flow resistance. A decrease in Richardson number also results in a decrease in friction factor and entropy generation. At the wake region of welding spots, the velocity has reached its lowest values; consequently, this led to a reduction in the heat transfer rate. Nevertheless, within dense porous media, at the lower hydraulic diameter points, the conduction contributes to heat transfer improvement. The porous medium acts as a heat sink and absorbs the heat from the welding spot. This allows the heat to be dissipated away from the welding spot, which reduces the velocity and heat transfer rate. The nanofluid, on the other hand, helps to increase the thermal conductivity of the medium, resulting in more heat being transferred to the surrounding material. Consequently, the results demonstrated that PPHEs' thermal and thermodynamic performance could be significantly improved by using a porous medium saturated with nanofluid