Composite Molding Research Articles

Comprehensive Composite Mould Filling Pattern Dataset for Process Modelling and Prediction

The Resin Transfer Moulding process receives great attention from both academia and industry, owing to its superior manufacturing rate and product quality. Particularly, the progression of its mould filling stage is crucial to ensure a complete reinforcement saturation. Contemporary process simulation methods focus primarily on physics-based approaches to model the complex resin permeation phenomenon, which are computationally expensive to solve. Thus, the application of machine learning and data-driven modelling approaches is of great interest to minimise the cost of process simulation. In this study, a comprehensive dataset consisting of mould filling patterns of the Resin Transfer Moulding process at different injection locations for a composite dashboard panel case study is presented. The problem description and significance of the dataset are outlined. The distribution of this comprehensive dataset aims to lower the barriers to entry for researching machine learning approaches in composite moulding applications, while concurrently providing a standardised baseline for evaluating newly developed algorithms and models in future research works.

A Novel Method for Fabricating the Undulating Structures at Dermal-Epidermal Junction by Composite Molding Process.

The dermal-epidermal junction (DEJ), located between the dermal-epidermal layers in human skin tissue, plays a significant role in its function. However, the limitations of biomaterial properties and microstructure fabrication methods mean that most current tissue engineered skin models do not consider the existence of DEJ. In this study, a nanofiber membrane that simulates the fluctuating structure of skin DEJ was prepared by the composite molding process. Electrospinning is a technique for the production of nanofibers, which can customize the physical and biological properties of biomaterials. At present, electrospinning technology is widely used in the simulation of customized natural skin DEJ. In this study, four different concentration ratios of poly (lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) nanofiber membranes were prepared based on electrospinning technology. We selected a 15%PLGA + 5%PCL nanofiber membrane with mechanical properties, dimensional stability, hydrophilicity, and biocompatibility after physical properties and biological characterization. Then, the array-based microstructure model was prepared by three-dimensional (3D) printing. Subsequently, the microstructure was created on a 15%PLGA + 5%PCL membrane by the micro-imprinting process. Finally, the cell proliferation and live/dead tests of keratinocytes (HaCaTs) and fibroblasts (HSFs) were measured on the microstructural membrane and flat membrane. The results showed that 15%PLGA + 5%PCL microstructure membrane was more beneficial to promote the adhesion and proliferation of HaCaTs and HSFs than a flat membrane.

Developing an Ex Vivo Pig Model for Teaching Ultrasound and Fluoroscopy-Guided Percutaneous Renal Access.

Introduction: Establishing percutaneous renal access is the key initial step to percutaneous nephrolithotomy; however, learning the technique during surgery for trainees is complicated by the number of approaches used to gain access, limited completion time during a breath hold. and attempt to minimize the number of passes through a kidney. There are many training models for percutaneous access commercially available all with their respective limitations. Our objective was to develop a low-cost, high-fidelity percutaneous access training model that addresses existing limitations and can be used with both ultrasound and fluoroscopy guidance. Methods: After a formal ethics exemption was attained, pig cadavers were harvested for flank, kidneys, and ureters. These were incorporated into a composite porcine tissue mould, created within a gelatin matrix. In the initial assessment, establishing percutaneous access under both ultrasound and fluoroscopy guidance was tested to refine usability. Once acceptable, its use during a training course was evaluated to assess impressions for use with ultrasound. Results: We were able to create a $45USD biodegradable model, which can facilitate percutaneous access using: fluoroscopy with intrarenal contrast; fluoroscopy with endoscopic guidance; and fluoro-less that is, ultrasound only. A cohort of 12 Canadian Postgraduate Year-3 residents who used the model for ultrasound access agreed that the model simulated a comparable tactile experience (58.33%) and anatomy (75%) to humans. Furthermore, majority of the residents agreed that model was easy to use with ultrasound guidance (91.67%), was a beneficial experience for their learning and future practice (83.33%) and if available would use to complement their intraoperative training (83.33%). Conclusion: We were able to develop a low-cost, preliminarily tested ex vivo pig model for percutaneous access compatible with multiple imaging modalities. We will continue refining our model and seek to understand its benefits when teaching percutaneous access to varying levels of learners.

Experimental and numerical analysis of drilled‐ and molded‐hole glass fiber reinforced polymer matrix (GFRP) composites

AbstractDrilling glass fiber reinforced polymer matrix (GFRP) composites typically causes burrs, splintering, and microcracks within the GFRP structure, as well as delamination, fiber pull‐out, and thermal degradation of the polymer matrix. Designing and manufacturing molded‐hole GFRP components, as opposed to drilling, has recently been proposed as a promising method for overcoming the issues associated with drilling, for which there is limited research. Specifically, the mechanical response of molded‐hole GFRP has not been fully addressed in the literature. In the present study, molded and drilled GFRP composites with epoxy matrix were fabricated by hand lay‐up, and then the samples were analyzed utilizing experimental and numerical analysis techniques. Stress and strain analyses of GFRP samples were performed in Ansys Transient Structural Analysis. Although the fiber orientations of the layer geometries [0°/90°] and 3D models were the same, an additional layer was defined in the direction of the fiber orientation [45°/−45°] of molded‐hole composites to simulate the fiber accumulation effect. Experimental findings revealed that the flexural strength of molded composites was 12% greater than that of drilled composites. According to the numerical analysis, 98.7% proximity was achieved between the experimental and numerical results. Thus, the present study has provided numerical modeling to understand the flexural strength of molded composites for the first time, which will contribute to the increased use of molded composites in numerous applications in the fields of aerospace, automotive, and marine.Highlights Drilled‐ and molded‐hole GFRP composites were produced by hand lay‐up. Flexural properties of the composites were examined via 4P bending tests. Flexural strength of molded composites was higher than that of drilled ones. 98.7% proximity was achieved between the experimental and FEM results. A unified FEM method is proposed for the molded‐hole composites.

Experimental process characterisation for high-volume compression moulding of hybrid-architecture composites

Compression moulding of woven fabric prepreg and sheet moulding compound (SMC) in a single-shot process combines the superior mechanical properties of continuous fibre composites and the high design flexibility of discontinuous fibre composites. This experimental study presents insights into the moulding characteristics of prepreg and SMC and explores the interaction between these two materials during manufacturing of hybrid-architecture composites. All tests were performed under typical compression moulding conditions using a squeeze flow testing rig. The response of each material was interpreted through proposed material models applied to the data acquired from single architecture tests. Critical interaction mechanisms were identified from hybrid architecture tests, alongside some additional deformation mechanisms, such as high level of in-plane fibre tow deformation not observed in single-architecture tests. Novel experimental methods were also introduced to quantify the change in meso-scale fibre architecture in the prepreg induced by the flow of SMC. The outcomes of this study not only shed light on the essential interaction mechanisms of hybrid-architecture composites but also provide valuable insights into deformation mechanisms not apparent in isolated material studies. Ultimately, these findings will facilitate the future development of a numerical simulation model for hybrid moulding processes.

Exploring productivity improvement consulting operation cases and development directions to foster the composite mold industry

Exploring productivity improvement consulting operation cases and development directions to foster the composite mold industry

Fibre orientation distribution function mapping for short fibre polymer composite components from low resolution/large volume X-ray computed tomography

Short glass fibre injection moulded composites, used in interior and exterior automotive parts, are exposed to complex stress states, for example during a crash. As the fibre scale dominates the composite’s material properties, numerical models need to account for the local fibre orientation. In recent years, mould flow simulation results have been exploited to predict the fibre orientations for finite element models, albeit with limited accuracy. Alternatively, X-ray computed tomography can be used to directly image and analyse fibre orientations. Traditionally, achieving the necessary resolution to image individual fibres restricts the imaging to small regions of the component. However, this study takes advantage of recent advancements in imaging and image analysis to overcome this limitation. As a result, it introduces, for the first time, a reliable, fast, and automated fibre orientation mapping for a full component based on image analysis at the individual fibre level; even for cases where the pixel size is significantly larger than the fibre diameter. By scanning at lower resolutions, a drastically larger volume of interest can be achieved. The resulting fibre orientation analysis and mapping algorithm, based on X-ray computed tomography, is well matched to the level of information required for automotive crash modelling with a standard element-size of a few millimetres. The entire process, encompassing image acquisition, image analysis and fibre orientation mapping, can be directly integrated into an industrial full component application in a matter of hours.

Infusion Simulation of Graphene-Enhanced Resin in LCM for Thermal and Chemo-Rheological Analysis.

The present numerical study proposes a framework to determine the heat flow parameters-specific heat and thermal conductivity-of resin-graphene nanoplatelets (GNPs) (modified) as well as non-modified resin (with no GNPs). This is performed by evaluating the exothermic reaction which occurs during both the filling and post-filling stages of Liquid Composite Moulding (LCM). The proposed model uses ANSYS Fluent to solve the Stokes-Brinkman (momentum and mass), energy, and chemical species conservation equations to a describe nano-filled resin infusion, chemo-rheological changes, and heat release/transfer simultaneously on a Representative Volume Element (RVE). The transient Volume-of-Fluid (VOF) method is employed to track free-surface propagation (resin-air interface) throughout the computational domain. A User-Defined Function (UDF) is developed together with a User-Defined Scaler (UDS) to incorporate the heat generation (polymerisation), which is added as an extra source term into the energy equation. A separate UDF is used to capture intra-tow (microscopic) flow by adding a source term into the momentum equation. The numerical findings indicate that the incorporation of GNPs can accelerate the curing of the resin system due to the high thermal conductivity of the nanofiller. Furthermore, the model proves its capability in predicting the specific heat and thermal conductivity of the modified and non-modified resin systems utilising the computed heat of reaction data. The analysis shows an increase of ∼15% in the specific heat and thermal conductivity due to different mould temperatures applied (110-170 °C). This, furthermore, stresses the fact that the addition of GNPs (0.2 wt.%) improves the resin-specific heat by 3.68% and thermal conductivity by 58% in comparison to the non-modified thermoset resin. The numerical findings show a satisfactory agreement with and in the range of experimental data available in the literature.

Sustainable Polypropylene-Based Composites with Agro-Waste Fillers: Thermal, Morphological, Mechanical Properties and Dimensional Stability.

Natural fiber composites (NFC) are eco-friendly alternatives to synthetic polymers. However, some intrinsic natural fillers' properties hinder their widespread implementation as reinforcement in polymeric matrices and require further investigation. In the scope of this study, the thermal, rheologic, mechanical (tension and flexural modes), and morphological properties, as well as the water absorption and dimensional stability of the NF polypropylene (PP)-based injection molded composites reinforced with rice husk (rh) and olive pits (op) of 20 wt.% and 30% wt.%, respectively, were investigated. The results suggest that the higher content of the rice husk and olive pits led to a similar reduction in the melt flow index (MFI), independent of the additive type compared to virgin polypropylene (PPv). The melting and crystallization temperatures of the PPrh and PPop composites did not change with statistical significance. The composites are stiffer than the PP matrix by up to 49% and possess higher mechanical strength in the tension mode at the expense of decreased ductility. PPrh and PPop have a superior flexural modulus in the bending mode, while the flexural strength improvement was accomplished for the PP30%rh. The influence of the fibers' distribution in the bulk of the parts on their mechanical performance was confirmed based on a non-localized morphology evaluation, which constitutes a novelty of the presented research. The dimensional stability of the composites was improved as the linear shrinkage in the flow direction was decreased by 49% for PPrh and 30% for PPop, positively correlating with an increase in the filler content and stiffness. PPop was less susceptible to water sorption than PPrh due to fibers' composition and larger surface-to-area volume ratios.

Manufacturing Process of Helicopter Tail Rotor Blades from Composite Materials Using 3D-Printed Moulds

Conventional processes require a mould for the manufacture of each test product, which often results in high costs but is ideal for large series of products. In contrast, for prototypes, additive manufacturing processes are a suitable low-cost time-saving alternative. The primary objective of this study is to investigate the capabilities of 3D-printed tooling in a real-life scenario for composite blades with low production numbers and prototypes in order to allow development and production costs to decrease and to also reduce lead times in the early phases of new projects. The 3D printing process is economically advantageous in terms of production costs for the composite blade mould, reducing the cost three times compared to the conventional manufacturing process. To obtain the composite helicopter blade, the following phases were carried out: the starting design of the mould, 3D printing and assembly of the mould sections, and blade manufacturing. The economic analysis of the two mould manufacturing methods shows an approximately equal ratio between the manufacturing costs of the 3D-printed mould and the manufacturing costs of the blade, whereas in the conventional processes, the costs for mould manufacturing represent 75% of the total cost and the rest (25%) of the cost is spent on blade manufacturing.

Airtight welding technology for aircraft composite mold panel

In this paper, the airtightness problem caused by welding defects in the manufacturing process of composite mold is analyzed. The mechanism analysis of the weld defects of composite mold is conducted. According to the mechanism of weld failure, the welding process monitoring, weld metallographic analysis, weld X-ray inspection, panel airtightness detection, and other methods are used to evaluate the welding quality of different welding forms in the welding process of composite mold panels. The measures to optimize the welding quality of composite mold panels are put forward. Finally, through the actual verification, it is proved that the optimized air-tightness welding method is stable and reliable.

Improving the technology of obtaining highquality castings from steel in sand-clay molds

This article examines the technology for producing high-quality steel and alloy castings in sand-clay molds. The optimization of the sandclay compound mold composition is explored, focusing on bentonite and kaolin clays as binders. The mold composition is refined based on the research conducted on these binding clays, resulting in the production of gas-free cast products. Additionally, the gas permeability of the sand-clay molds increased by 14-16%. The study also presents a test analysis of the gas permeability property, a crucial aspect of sand-clay mold quality. Furthermore, a mathematical model of the process was developed from the research findings to predict gas permeability values with varying amounts of binding clays, eliminating the need for further testing.

Thermo-mechanical characterisation of polycarbonate-based sheet moulded composites fabricated from off-cut waste unidirectional tapes

Thermo-mechanical characterisation of polycarbonate-based sheet moulded composites fabricated from off-cut waste unidirectional tapes

Influence of Epoxy Spray Binder on Infusion and Cure in Liquid Composite Molding Processes

Binders are known to influence the different steps in liquid composite molding process chains. Most reseach focuses on powder binder and veils. Spray binders are rarely studied. Therefore, the effect of an epoxy spray binder on the infusion and cure steps of liquid composite molding processes is studied in this paper. Permeability measurements, solubility tests and measurements of glass transition temperature, resin cure time and resin viscosity show a complex interaction between binder and resin depending on the process conditions. The binder mostly increased the permeability of the tested preforms. This effect increases with increasing binder loading. At low fiber volume fractions the binder had a positive effect on preform permeability, most likely by to delaying the closure of macro flow channels or textile inhomogeneity. The binder did not dissolve in the resin until temperatures of around 120 °C, while remaining as a separate phase at 22 °C, 40 and 80 °C. This has to be considered when defining the cure profile of the resin, as the binder is expected to participate in the cure reaction. The glass transition temperature remained unchanged for the binder-resin combination used. An increase in viscosity by a factor of 1.5-2 was observed when the binder was dissolved in the resin. Samples with dissolved binder cured slightly faster than pure resin. The experimental results were theoretically transferred to real infusion processes.

Experimental Validation of Reconstructed Microstructure via Deep Learning in Discontinuous Fiber Platelet Composite

Abstract A novel approach for microstructure reconstruction using artificial intelligence (MR-AI) was proposed to nondestructively measure the through-thickness average stochastic fiber orientation distribution (FOD) in a prepreg platelet molded composite (PPMC) plate. MR-AI approach uses thermal strain components on the surfaces of a PPMC plate as input to the deep learning model, which allows to predict a distribution of local through-thickness average fiber orientation state in the entire PPMC volume. The experimental setup with a heating stage and digital image correlation (DIC) was used to measure thermal strains on the surface of the PPMC plate. Optical microscopy was then used to measure FOD in the cross section of the PPMC plate. FOD measurements from optical microscopy imagery compared favorably with FOD prediction by MR-AI. The proposed methodology opens the opportunity for rapid, nondestructive inspection of manufacturing-induced FOD in molded composites.

Preparation and Performance of High Thermal Conductivity Polypropylene-based Composites

Polypropylene-based composites with high thermal conductivity were obtained by pressure injection molding using a hybrid form of PP as the matrix and FG as the thermally conductive filler with a particle size of 37 µm. Microscopic morphologies of the material were examined by SEM to determine the effect of FG content on the thermal conductivity and mechanical properties of the composites. The study found a clear correlation between the thermal conductivity of the composites and the FG content. The research confirmed a direct link between the thermal conductivity of the composites and FG content. At 70 wt%, the material demonstrated the greatest average, axial, and radial thermal conductivity of 7.52 W·m-1·K-1, 12.6 W·m-1·K-1, and 4.50 W·m-1·K-1, respectively. However, any subsequent increase in fractional gradient (FG) content resulted in a decrease in the strength and modulus of the material. The highest tensile and flexural strength values of 34.9 and 63.7 MPa respectively, were achieved when the FG content was 60 wt%. At this particular FG content, the tensile and flexural modulus also reached 9.78 and 10.7 gigapascals (GPa), respectively. As the FG content increased, the strain on the composite material decreased. Note that the maximum tensile and flexural strains were measured at 50 wt% FG content, with values of 0.77% and 0.79%, respectively. The glass fiber sheets in the injection molded composites were uniform and predominantly vertically oriented.

Review of Approaches to Minimise the Cost of Simulation-Based Optimisation for Liquid Composite Moulding Processes.

The utilisation of numerical process simulation has greatly facilitated the challenging task of liquid composite moulding (LCM) process optimisation, providing ease of solution evaluation at a significantly reduced cost compared to complete reliance on physical prototyping. However, due to the process complexity, such process simulation is still considerably expensive at present. In this paper, cost-saving approaches to minimising the computational cost of simulation-based optimisation for LCM processes are compiled and discussed. Their specific applicability, efficacy, and suitability for various optimisation/moulding scenarios are extensively explored in detail. The comprehensive analysation and assimilation of their operation alongside applicability for the problem domain of interest are accomplished in this paper to further complement and contribute to future simulation-based optimisation capabilities for composite moulding processes. The importance of balancing the cost-accuracy trade-off is also repeatedly emphasised, allowing for substantial cost reductions while ensuring a desirable level of optimization reliability.

Mechanical, Thermal, Morphological, and Fibre Characteristics During Injection Moulding of Green Composites

Mechanical, Thermal, Morphological, and Fibre Characteristics During Injection Moulding of Green Composites

Biocomposite Innovation: Assessing Tensile and Flexural Performance with Maleated Natural Rubber Additives

Fiberglass is the most common reinforcing fiber used in composites, with polymer matrices having high tensile strength and chemical resistance, including an excellent insulating property; however, they are non-degradable. Natural fiber reinforced polymer composites have advantageous properties such as lower density and price, when compared to synthetic composite products. In addition, hybrid composites may be obtained depending on various properties such as the fibers' length, structure, content and orientation, matrix bonding and arrangement. This study was carried out to determine the effect of adding Maleated Natural Rubber (MNR) from natural rubber as a coupling agent, in order to produce the highest tensile and flexural strength. The hand lay-up and vacuum bag methods with the Response Surface Method-Central Composite Design (RSM). -CCD) were used. The composite arrangement pattern was E-glass/OPEFB/E-glass, the volume fraction of OPEFB (oil palm empty fruit bunches):E-glass was 40:60, 50:50 and 60:40, the fraction volume of OPEFB + E-glass:matrix was 40:60, 50: 50, 60: 40 and the coupling agent were added by 9, 10 and 11% of the total epoxy resin used. Furthermore, the composite mold was made of glass with dimensions of 200mm x 50mm x 50mm. The results showed that the composite product obtained from both methods had a tensile strength value, which was influenced by the variable OPEFB fiber and epoxy resin. Meanwhile, the flexural strength was influenced by the OPEFB fiber and the quadratic factor of the epoxy-MNR resin.

Pengaruh Lebar Cetakan Komposit Karbon Aktif-Tembaga (ii) Oksida terhadap Karakteristik Termoelektrik

This research aims to determine the effect of the width of the C-CuO composite mold on the characteristics of thermoelectric materials. The composite is made from activated carbon mixed with CuO in a ratio of 3 grams of activated carbon: 7 grams of CuO which is then molded with five variations in the width of the mold for the C-CuO composite, namely 1 cm, 1.3 cm, 1.6 cm, 2 cm and 2.5 cm. In testing the electrical conductivity and Seebeck effect on the C-CuO composite, the values were almost the same, in other words the electric current produced was not influenced by the mold width of the C-CuO composite. Meanwhile, on the heat conductivity day value, the mold width has an influence as the applied temperature increases. Where the optimum heat conductivity value is produced in material with a width of 1 cm.