Papers by Keyword: Composite

Abstract: Natural fiber-based composites are increasingly used in engineering applications due to their superior performance in producing lightweight, strong, and environmentally friendly materials. This study compares hot-pressed resin composites reinforced with teak sawdust become Teak sawdust Reinforced-Hot Pressed Resin Composite (TSR-HPRC) and coconut fiber became Reinforced Hot Pressed Resin CompositeCoconut coir Reinforced (CCR-HPRC). Teak sawdust is a wood industry waste with high strength and aesthetic value, while coconut fiber comes from coir and is abundant in tropical regions. Both are used as reinforcements for composite resins to improve mechanical properties. Through the hot-pressing method, this study evaluated the tensile strength, hardness, and coefficient of friction of TSR-HPRC and CCR-HPRC. Thorough testing was carried out, including statistical analysis (ANOVA) to determine the optimal reinforcement conditions. The results showed that TSR-HPRC had the highest tensile strength of 22.78 MPa and Shore D hardness of 80.87, superior to CCR-HPRC which only achieved 10.48 MPa and hardness of 76.55. The friction coefficient of TSR-HPRC ranges from 0.25–0.33, while that of CCR-HPRC ranges from 0.17–0.24. This study supports the development of cost-effective and sustainable composite materials, reducing dependence on synthetic fibers.

Abstract: This study focuses on the development of sustainable composite materials for automotivebody panels by utilizing sugarcane bagasse and bamboo fibers reinforced with epoxy resin. Theagricultural by-products were first sun-dried, mechanically processed into fine powder, andchemically treated to improve interfacial bonding before being incorporated into the epoxy matrix.Composite specimens were fabricated through a controlled lay-up process and tested for flexuralstrength and impact resistance in accordance with ASTM standards. Experimental results revealedthat sugarcane bagasse composites exhibited the highest flexural strength of 47 MPa, while bamboocomposites contributed greater ductility and flexibility under load. Notably, a hybrid formulation ofbagasse and bamboo fibers achieved the best balance of properties, recording an impact resistance of187 J/m, which is comparable to commonly used polymers. These findings highlight that naturalfiber-based composites not only offer mechanical performance suitable for exterior automotiveapplications but also provide significant advantages in terms of weight reduction, cost-effectiveness,and environmental sustainability.

Abstract: Industrial wastewater often contains colored toxic dyes and heavy metals that harm ecosystems and human health, highlighting the need for sustainable treatment strategies. This study aimed to develop a guar gum (GG)/polyacrylamide (PAAm)/rice straw biochar (RSBC) hydrogel grafted onto polyethylene terephthalate (PET) (GG/PAAm RSBC-g-PET) textile, and its structure was characterized through swelling behavior, FTIR-ATR spectroscopy, and Scanning Electron Microscopy (SEM) analysis. The modified GG/PAAm/RSBC-g-PET exhibits a significant increase in water absorption compared to GG/PAAm-g-PET. The alteration and shifted peaks were observed particularly at bands of 3441 cm^-1 (RSBC), and 852 cm^-1 (galactose and mannose units), imparting effective crosslinking. SEM analysis revealed a porous structure with irregular magnetite particles, enhancing the active surface area. The performance of the GG/PAAm/RSBC-g-PET composite was evaluated using industrial wastewater, which resulted in reduced turbidity (26.5 NTU) and color (~49.5 ADMI), compared to filtration with PET textile alone (47 NTU and ~69.5 ADMI). The GG/PAAm/RSBC-g-PET composite exhibits comparable yet inconsistent improvements, possibly due to particle release and pore blockage. These findings demonstrate the feasibility of the GG/PAAm/RSBC-g-PET textile for decolorization, indicating its potential application in wastewater remediation.

Abstract: Present demands for weight reduction of vehicles to decrease the carbon footprint in the transport industry have increased the need for lightweight tubes. In this paper, composite tubes are drawn from two aluminum tubes and reinforcements with the aim of maximizing mechanical performance while maintaining low weight. The reinforcements are placed between the two aluminum tubes and are made from blanks of 22MnB5 steel or carbon fiber laid in different quantities and patterns. The compressive stresses in tube sinking are used to hold the reinforcements in the composites without the need for resins and energy-intensive heating or curing cycles. The composites are weighed, and their performance is evaluated by mechanical test. Bending tests reveal an increase in the bending strength of the reinforced tubes by 15% for both composites reinforced by carbon fiber and 22MnB5 steel. However, the composites made from carbon fiber have higher stiffness and lower weight. The bending strength and residual stresses of composites manufactured with different carbon fiber layouts and quantities are evaluated to determine their performance. Increasing the carbon fiber content did not improve the stiffness and ultimate tensile strength of the composites, indicating the compressive stresses from drawing and carbon fiber content should be optimized to achieve the best mechanical performance.

Abstract: The objective of the present research was to identify the mechanical properties of 3D-printed biocomposite parts and their variation with different natural fillers (olive wood and almond shell). The materials were produced by filament extrusion with 5% fiber content in the polylactic acid matrix, and the samples were fabricated using the Material Extrusion Additive Manufacturing process. 3D printed specimens underwent tensile and flexural tests to assess their mechanical properties. The results showed reductions of 5%-18% in the tensile modulus and 10%-38% in the tensile strength for olive wood-and almond shell-based PLA, respectively. The same trend was detected for the flexural properties, with a slight reduction of 2%-3% in the flexural modulus and 3%-5% in flexural strength.

Abstract: Epoxy-based composites used in the aerospace industry are highly sensitive to moisture absorption, which can lead to porosity formation during the curing process and compromise structural integrity. Therefore, accurate prediction of temperature fields, degree of cure, and moisture concentration is essential for process optimization and defect mitigation. However, classical numerical approaches for solving the coupled governing equations are computationally expensive, limiting their applicability in real-time analyses and optimization strategies. In this work, Physics-Informed Neural Networks (PINNs) are investigated for predicting the transient thermal behavior, cure kinetics, and moisture concentration in an epoxy composite laminate during autoclave curing. Two PINNs are developed: the first solves the coupled transient heat transfer and cure kinetics equations in a compositetooling system, while the second predicts the moisture concentration field in the laminate using the temperature information provided by the first network. Different network architectures are evaluated, and their performance is compared with numerical solutions obtained via the Finite Volume and Finite Element Methods. The results demonstrate that PINNs accurately reproduce temperature profiles, degree of cure, and moisture concentration, achieving high coefficients of determination, while also providing significant computational efficiency advantages during the prediction stage. These findings highlight the potential of PINNs as a robust and efficient tool for modeling complex coupled phenomena in composite manufacturing processes.

Abstract: Wood-filled PLA filaments enable 3D pyrography in material-extrusion (MEX) printing, in which tonal gradients and surface shading are generated in situ by controlling the thermal history during deposition, thereby avoiding post-processing or multi-material strategies. This enables the direct embedding of motifs and graded shading for customized product design, while also allowing appearance stabilization for repeatable manufacturing of wood-filled PLA parts. In this work, PLA/olive-wood (OW) composite filaments containing 0-20 wt.% OW (particle size < 180 µm) were manufactured and printed into 20 mm discs using MEX. The extrusion (nozzle) temperature was varied from 180 to 280 °C, and the printing speed was set to 20 and 200 mm/s to modulate thermal exposure. Surface color was quantified as L^*, a^*, b^* from visible absorbance measurements (400-700 nm) converted into CIELAB coordinates. Percentual differences were assessed using the CIEDE2000 metric ΔE₀₀. The results demonstrated that increasing nozzle temperature progressively reduced lightness L^*, and under severe conditions, a marked loss of chroma (a^* and b^*), particularly for higher OW contents. Low-speed printing (20 mm/s) amplified the pyrographic effect, reaching strong perceptual contrasts (maximum ΔE₀₀ ≈ 9 at 280 °C for 20 wt.% OW), whereas high-speed printing (200 mm/s) mitigated extreme darkening and maintained more moderate, controlled color differences (typically ΔE₀₀ < 3). Accordingly, ΔE00< 3 can be used as a practical “color-stable” target for uniform-looking parts, whereas ΔE00= 3-9 provides clearly distinguishable shades for pyrographic marking/shading. These findings defined practical process windows to either maximize tonal contrast for 3D pyrography or stabilize the appearance for consistent manufacturing of PLA/OW parts.

Abstract: A novel solution for monitoring the infusion process and providing decision support to operators involved in the manufacturing of large, unique or near-unique parts is presented. Based on a scientific approach referred to as the 5D methodology (D for dimensions), the proposed solution consists of a process digital twin built upon a metamodel that is fed in real time by signals from sensors embedded in the process, enabling the anticipation of defects such as dry spots.

Abstract: Incremental Sheet Forming (ISF) enables the flexible creation of shell-shaped structures. Unlike conventional forming, ISF does not require a bespoke forming tool, greatly reducing upfront costs and lead times, especially for small lot sizes. Several parameter classifications for the ISF of metals and polymers have been proposed in the past. Such classifications increase awareness of possible levers for process optimization, guide experimental analysis, and enable a holistic understanding. Lately, fiber-reinforced polymers (FRP) are of increasing interest in ISF. In previous studies, ISF systems for various kinds of FRP have been developed, and several parameters and target variables have been investigated. However, there is currently no classification that addresses the specific parameters and target variables relevant to this material class. Therefore, the goal of this work is to develop such a classification to create a comprehensive foundation for future FRP ISF investigations. This effort is undertaken by building upon existing classifications and reviews independent of the material class and synthesizing these with a systematic literature review of FRP ISF investigations. The resulting classifications cover a broad range of parameters and target variables and reveal a structure that guides a systematic understanding and ensures future expandability.

Abstract: Fiber-reinforced thermoplastics (FRTP) offer high strength-to-weight ratios as well as weldability and recyclability, making them attractive for lightweight applications. Conventional thermoforming of continuous FRTP, however, requires part-specific molds, limiting economic viability for prototypes, individual parts, and small series. This study investigates a robotic hot double-sided incremental forming (DSIF) process developed for dieless, flexible forming of continuous FRTP sheets together with metal dummy sheets. Five different generic demonstrator parts with varying wall angles, degrees of symmetry, forming depths, and sizes were formed to assess process capability. Results demonstrate that typical defects such as fabric wrinkling and deconsolidation can be successfully avoided, and that the geometric accuracy achievable is comparable to that of metal DSIF. Challenges exist in forming larger parts due to the failure of the employed metal dummy sheets.