Fabrication Sequence Research Articles

Assessment of mechanical and thermal properties of hybrid co-woven biofiber polymer composites

The recent research explores the hybridizing effect of inter and intra woven natural engineering fibers in epoxy composites. The inter and intra woven brown flax (Fb), white flax (Fw), and jute (J) fabrics have been comingled with short coir fibers (SCF). The composites are successfully made using the hand layup procedure, and the successive arrangement of fabrics is based on the tensile characteristics of inter and intra-woven fabrics. The physical, thermal, and mechanical characteristics of composites are experimentally studied. The C1 composite having (Fb+Fw)/Fw/J/J/Fw/(Fb+Fw) fabric sequence without filler demonstrated highest tensile strength of 30.15 MPa, elastic modulus of 2164.59 MPa, flexural strength of 66.46 MPa, and flexural modulus of 3900.74 MPa. However, the C3 composite containing SCF filler, having a similar fabric sequence as that of C1 demonstrated highest impact strength of 116.52 KJ/m2. Thermogravimetric analysis (TGA) revealed that the composite C3 exhibited better thermal stability than other hybrid patterns. Fourier transform infrared (FTIR) spectroscopy study confirmed the interaction of hydrogen bonds with different polymers, matrices, and fillers. Further, microstructural and fractography analysis have been done to analyze the surface phenomena of the composites and mechanical failure analysis.

Space–time topology optimization for anisotropic materials in wire and arc additive manufacturing

Wire and Arc Additive Manufacturing (WAAM) has great potential for efficiently producing large metallic components. However, like other additive manufacturing techniques, materials processed by WAAM exhibit anisotropic properties. Assuming isotropic material properties in design optimization thus leads to less efficient material utilization. Instead of viewing WAAM-induced material anisotropy as a limitation, we consider it an opportunity to improve structural performance. This requires the integration of process planning into structural design. In this paper, we propose a novel method to utilize material anisotropy to enhance the performance of structures both during fabrication and in their use. Our approach is based on space–time topology optimization, which simultaneously optimizes the structural layout and the fabrication sequence. To model material anisotropy in space–time topology optimization, we derive the material deposition direction from the gradient of the pseudo-time field, which encodes the fabrication sequence. Numerical results demonstrate that leveraging material anisotropy effectively improves the performance of intermediate structures during fabrication as well as the overall structure.

Elastomer-based soft syntactic foam with broadly tunable mechanical properties and shapability

Fabrication of lightweight composites using thermally responsive expandable microspheres (EM) embedded in an elastomeric matrix to form syntactic foams offers significant opportunities to create functional and structural composites for diverse applications. The morphology of the EM-elastomer composite on the micro- and macro-scales is significantly influenced by the fabrication sequence and parameters (composition, expansion time/temperature, etc.). Herein, we report the morphological evolution of an EM-elastomer composite through the fabrication processes and elucidate the interaction of relevant fabrication parameters. Unlike the majority of published reports on hard EM composites, the in-situ expansion of the closed-cell foam structure within a soft matrix leads to larger void sizes, and the concomitant expansive force of the EM impacts the polymer chain mobility within the soft composite. At the same time, higher EM loading improves the mechanical properties; the evolved microstructure leads to a lightweight but stiff structure. For the first time the report details the thermal expansion of EM under applied pretension, leading to irreversible prestrain-dependent morphological changes toward anisotropic mechanical properties. Additionally, the composites are shaped under constrained expansion. The study provides a comprehensive guide and expands the pathways for the practical application of EM-embedded soft syntactic foams in aerospace, electronics, wearables, robotics, etc.

Regularization in space–time topology optimization for additive manufacturing

In additive manufacturing, the fabrication sequence has a large influence on the quality of manufactured components. While planning of the fabrication sequence is typically performed after the component has been designed, recent developments have demonstrated the possibility and benefits of simultaneous optimization of both the structural layout and the corresponding fabrication sequence. This is particularly relevant in multi-axis additive manufacturing, where rotational motion offers enhanced flexibility compared to planar fabrication. The simultaneous optimization approach, called space–time topology optimization, introduces a pseudo-time field to encode the manufacturing process order, alongside a pseudo-density field representing the structural layout. To comply with manufacturing principles, the pseudo-time field needs to be monotonic, i.e., free of local minima. However, explicitly formulated constraints proposed in prior work are not always effective, particularly for complex structural layouts that commonly result from topology optimization.In this paper, we introduce a novel method to regularize the pseudo-time field in space–time topology optimization. We conceptualize the monotonic additive manufacturing process as a virtual heat conduction process starting from the surface upon which a component is constructed layer by layer. The virtual temperature field, which shall not be confused with the actual temperature field during manufacturing, serves as an analogy for encoding the fabrication sequence. In this new formulation, we use local virtual heat conductivity coefficients as optimization variables to steer the temperature field and, consequently, the fabrication sequence. The virtual temperature field is inherently free of local minima due to the physics it resembles. We numerically validate the effectiveness of this regularization in space–time topology optimization under process-dependent loads, including gravity and thermomechanical loads.

TSLAM: a tag-based object-centered monocular navigation system for augmented manual woodworking

TimberSLAM (TSLAM) is an object-centered, tag-based visual self-localization and mapping (SLAM) system for monocular RGB cameras. It was specifically developed to support a robust and augmented reality pipeline for close-range, noisy, and cluttered fabrication sequences that involve woodworking operations, such as cutting, drilling, sawing, and screwing with multiple tools and end-effectors. By leveraging and combining multiple open-source projects, we obtain a functional pipeline that can map, three-dimensionally reconstruct, and finally provide a robust camera pose stream during fabrication time to overlay an execution model with its digital-twin model, even under close-range views, dynamic environments, and heavy scene obstructions. To benchmark the proposed navigation system under real fabrication scenarios, we produce a data set of 1344 closeups of different woodworking operations with multiple tools, tool heads, and varying parameters (e.g., tag layout and density). The evaluation campaign indicates that TSLAM is satisfyingly capable of detecting the camera’s millimeter position and subangular rotation during the majority of fabrication sequences. The reconstruction algorithm’s accuracy is also gauged and yields results that demonstrate its capacity to acquire shapes of timber beams with up to two preexisting joints. We have made the entire source code, evaluation pipeline, and data set open to the public for reproducibility and the benefit of the community.Graphic abstract

EXPERIMENTAL ANALYSIS OF THE EFFECT OF THE WOVEN ARAMID FABRIC ON THE STRAIN TO FAILURE BEHAVIOR OF PLAIN WEAVED CARBON/ARAMID HYBRID LAMINATES

Remarkable advances in the research and development of micro/mini Unmanned Aerial Vehicles (UAVs) seek thin, lightweight and strong materials for their structural applications. As these structures involve various loading conditions in both the in-plane and through-the-thickness directions during their life cycle, the assurance of the structural stability in each direction is deemed mandatory. The woven Aramid fibers as high strain materials (HSM) are known to improve the through-the-thickness impact strength. However, the addition of the HSM can affect the overall tensile behavior of composite laminates. This study investigates the effect of the woven Aramid fiber on the in-plane tensile behavior of Carbon/ epoxy laminates. Laminates are fabricated using an easy and cost-effective Vacuum Assisted Resin Infusion Molding (VARIM) setup. A uniaxial tensile test was conducted to analyze the tensile behavior of Carbon/Aramid hybrid composites. The effect of adding the woven Aramid layer and the Carbon fabric sequence on the tensile modulus, strain to failure and modulus of toughness are investigated in this study. The results revealed that the presence of Aramid has a positive hybrid effect on the failure strain, exhibiting pseudo-ductile behavior with a compromise in the tensile modulus of the virgin Carbon/epoxy laminate.

PFS 1.0: A development tool applied to vision-based tactile sensor process formulation and fabrication

Vision-based tactile sensors (VBTS) have gradually garnered attention for their high performance. However, there is a lack of detailed technology summaries and available tools for process formulation. To simplify the development flow, this paper proposes a process formulation system (PFS) and establishes a visualization interface based on QT. The developer inputs the design goal, and the system automatically corrects these goals and then matches the process schemes by dictionary search. Following the fabrication sequence, the system outputs a complete reference fabrication flow. Furthermore, the PFS provides more comprehensive process details than large models. In addition, the PFS universality is verified via representative VBTS cases. A multimodal visuo-tactile skin (VTS) is developed with the PFS. The fabrication process of elastomer and coating is optimized based on the reference process. The results show that the VTS prototype achieves micron-level spatial resolution, high sensitivity, and high abrasion resistance. Consequently, the PFS is expected to provide technology guidance and assistant development for beginners and developers in this area.

Moisture diffusion and tensile properties of epoxy-based and polyurethane-based flax-glass hybrid FRP under hygrothermal and weathering environments

This research presents tensile modulus and strength of flax-glass hybrid FRP (HFRP) flat coupons with different fibre volume fractions and fabric stacking sequences under constant hygrothermal (50 °C and 95% RH) and cyclic weathering (water spray-ultraviolet radiation) environments for six months. Two types of polymer (i.e., epoxy (EP) and polyurethane (PUR)) were employed in HFRP. Fourier transformed infrared spectroscopy (FTIR) was performed to identify the changes in functional groups of flax fibres and polymer matrix after exposures. The glass transition temperature (Tg) of polymer matrix was measured by differential scanning calorimetry (DSC), which was used to study the influence of environmental exposure on Tg. The 3D diffusion coefficients of EP-based flax FRP and glass FRP laminates were determined based on experimental moisture uptake and Fick's law. A coupled mass diffusion-stress analysis based on finite element (FE) model was conducted to simulate the moisture diffusion and swelling behaviour of HFRP. The results showed that hygrothermal and weathering exposures hardly affected tensile modulus of HFRP regardless of the matrix type. After the environmental exposure, EP-based HFRP experienced lower retention ratio of tensile strength (65.4–88.0%) compared to PUR-based HFRP (80.7–94.1%) because of higher moisture absorption in the EP-based HFRP. The influence of fabric stacking sequence on tensile strength reduction varied with different fibre volume fractions in EP-based HFRP, which was explained by the combined effects of the internal stress and damage propagation at flax-glass interface.

A shield of defense: Developing ballistic composite panels with effective electromagnetic interference shielding absorption

The primary goal of this study is to develop cost-effective shield materials that offer effective protection against high-velocity ballistic impact and electromagnetic interference (EMI) shielding capabilities through absorption. Six fiber-reinforced epoxy composite panels, each with a different fabric material and stacking sequence, have been fabricated using a hand-layup vacuum bagging process. Two panels made of Kevlar and glass fibers, referred to as (K-NIJ) and (G-NIJ), have been tested according to the National Institute of Justice ballistic resistance protective materials test NIJ 0108.01 Standard-Level IIIA (9 mm × 19 mm FMJ 124 g) test. Three panels, namely, a hybrid of Kevlar and glass (H–S), glass with ceramic particles (C–S), and glass with recycled rubber (R–S) have been impacted by the bullet at the center, while the fourth panel made of glass fiber (G-S) has been impacted at the side. EMI shielding properties have been measured in the X-band frequency range via the reflection-transmission method. Results indicate that four panels (K-NIJ, G-NIJ, H–S, and G-S) are capable of withstanding high-velocity impact by stopping the bullet from penetrating through the panels while maintaining their structural integrity. However, under such conditions, these panels may experience localized delamination with variable severity. The EMI measurements reveal that the highest absorptivity observed is 88% for the K-NIJ panel at 10.8 GHz, while all panels maintain an average absorptivity above 65%. All panels act as a lossy medium with a peak absorptivity at different frequencies, with K-NIJ and H–S panels demonstrating the highest absorptivity. In summary, the study results in the development of a novel, cost-effective, multifunctional glass fiber epoxy composite that combines ballistic and electromagnetic interference shielding properties. The material has been developed using a simple manufacturing method and exhibits remarkable ballistic protection that outperforms Kevlar in terms of shielding efficiency; no bullet penetration or back face signature is observed, and it also demonstrates high EMI shielding absorption. Overall, the materials developed show great promise for various applications, including the military and defense.

Chemical mechanical planarization for Ta-based superconducting quantum devices

We report on the development of a chemical mechanical planarization (CMP) process for thick damascene Ta structures with pattern feature sizes down to 100 nm. This CMP process is the core of the fabrication sequence for scalable superconducting integrated circuits at a 300 mm wafer scale. This work has established the elements of various CMP-related design rules that can be followed by a designer for the layout of circuits that include Ta-based coplanar waveguide resonators, capacitors, and interconnects for tantalum-based qubits and single flux quantum circuits. The fabrication of these structures utilizes a 193 nm optical lithography along with 300 mm process tools for dielectric deposition, reactive ion etch, wet-clean, CMP, and in-line metrology—all tools typical for a 300 mm wafer CMOS foundry. Theprocess development was guided by measurements of the physical and electrical characteristics of the planarized structures. Physical characterization such as atomic force microscopy across the 300 mm wafer surface showed that local topography was less than 5 nm. Electrical characterization confirmed low leakage at room temperature, and less than 12% within wafer sheet resistance variation for damascene Ta line widths ranging from 100 nm to 3 μm. Run-to-run reproducibility was also evaluated. Effects of process integration choices including the deposited thickness of Ta are discussed.

Fabrication sequence optimization for minimizing distortion in multi-axis additive manufacturing

Additive manufacturing of metal parts involves phase transformations and high temperature gradients which lead to uneven thermal expansion and contraction, and, consequently, distortion of the fabricated components. The distortion has a great influence on the structural performance and dimensional accuracy, e.g., for assembly. It is therefore of critical importance to model, predict and, ultimately, reduce distortion. In this paper, we present a computational framework for fabrication sequence optimization to minimize distortion in multi-axis additive manufacturing (e.g., robotic wire arc additive manufacturing), in which the fabrication sequence is not limited to planar layers only. We encode the fabrication sequence by a continuous pseudo-time field, and optimize it using gradient-based numerical optimization. To demonstrate this framework, we adopt a computationally tractable yet reasonably accurate model to mimic the material shrinkage in metal additive manufacturing and thus to predict the distortion of the fabricated components. Numerical studies show that optimized curved layers can reduce distortion by orders of magnitude as compared to their planar counterparts.

Revealing the complexity of ultra-soft hydrogel re-swelling inside the brain

The brain is an ultra-soft viscoelastic matrix. Sub-kPa hydrogels match the brain's mechanical properties but are challenging to manipulate in an implantable format. We propose a simple fabrication and processing sequence, consisting of de-hydration, patterning, implantation, and re-hydration steps, to deliver brain-like hydrogel implants into the nervous tissue. We monitored in real-time the ultra-soft hydrogel re-swelling kinetics in vivo using microcomputed tomography, achieved by embedding gold nanoparticles inside the hydrogel for contrast enhancement. We found that re-swelling in vivo strongly depends on the implant geometry and water availability at the hydrogel-tissue interface. Buckling of the implant inside the brain occurs when the soft implant is tethered to the cranium. Finite-element and analytical models reveal how the shank geometry, modulus and anchoring govern in vivo buckling. Taken together, these considerations on re-swelling kinetics of hydrogel constructs, implant geometry and soft implant-tissue mechanical interplay can guide the engineering of biomimetic brain implants.

High Frequency MEMS Capacitive Mirror for Space Applications.

Free space optics laser communication using modulating retroreflectors (MR) is a challenging application for an active mirror, due to the high frequencies (>100 kHz) required to enable sufficient data transfer. Micro Electromechanical (MEMS) mirrors are a promising option for high-frequency applications, given the very small moving mass typical of such devices. Capacitive MEMS mirrors are presented here for free space communications, based on a novel fabrication sequence that introduces a single-layer thin film aluminum mirror structure with an underlying silicon oxide sacrificial layer. The use of aluminum instead of gold as a mirror layer diminishes the heating generated by the absorption of the sun's radiation once the mirrors exit the earth's atmosphere. Thanks to the novel fabrication sequence, the presented mirror devices have a full range actuation voltage of less than 40 V, and a high operational frequency with an eigenfrequency above 2 MHz. The devices were manufactured and characterized, and their main parameters were obtained from experimental data combined with finite element analysis, thus enabling future design optimization of the reported MEMS technology. By optical characterization of the far field diffraction pattern, good mirror performance was demonstrated.

Convexity and Surface Quality Enhanced Curved Slicing for Support-Free Multi-Axis Fabrication

In multi-axis fused deposition modeling (FDM) printing systems, support-free curved layer fabrication is realized by continuous transition of the printer nozzle orientation. However, the ability to print 3D models with complex geometric (e.g., high overhang) and topological (e.g., high genus) features is often restricted by various manufacturability constraints inherent to a curved layer design process. The crux in a multi-axis printing process planning pipeline is to design feasible curved layers and their tool paths that will satisfy both the support-free condition and other manufacturability constraints (e.g., collision-free). In this paper, we propose a volumetric curved layer decomposition method that strives to not only minimize (if not prevent) collision-inducing local shape features of layers, but also enable adaptive layer thickness to comply with a new volumetric error-based surface quality criterion. Our method computes an optimal Radial Basis Functions (RBF) field to modify the fabrication sequence field, from which, the iso-surface layers are extracted to design the corresponding multi-axis printing tool paths. A method to fine-tune variable nozzle orientations on each resulting curved layer is then proposed to overcome possible collisions in high-genus geometries. To validate the concept and exhibit its potential, several support-free fabrication experiments and comparisons with the conventional geodesic field-based slicing are presented, and the results give a preliminary confirmation of the feasibility and advantages of the proposed method.

Flexural behaviour of wood beams strengthened by flax-glass hybrid FRP subjected to hygrothermal and weathering exposures

This paper addressed the flexural behaviour (i.e., maximum load, ductility index, flexural strength and stiffness) of laminated veneer lumber (LVL) beams strengthened by 2-layer flax-glass hybrid fibre reinforced polymer (HFRP) exposed to hygrothermal (50℃ and 95% RH) and weathering (cyclic water spray-ultraviolet radiation) conditions for one month. Effects of environmental exposure and fabric sequences on flexural behaviour of LVL-HFRP beams were studied. LVL-FG and LVL-GF beams (inner plies bonded to LVL were flax and glass fibres, respectively) were tested under four-point bending. Tensile test on HFRP flat coupons was also conducted to provide the tensile parameters of HFRP in LVL-HFRP beams. This study showed that the hygrothermal and weathering exposures reduced the maximum load (by 11.4–32.2%), flexural strength (by 19.1–40.0%) and increased the ductility index (by 18.3–41.7%) of LVL-HFRP beams. The hygrothermal exposure did not affect flexural stiffness. The fabric sequence affected the flexural behaviour of LVL-HFRP beams. LVL-GF beams showed lower maximum load and flexural strength than those of the LVL-FG beams, which was attributed to the HFRP delamination in the LVL-GF beams. A theoretical prediction model for the ultimate bending moments of LVL-HFRP beams was used, and the calculated values showed a good agreement with the experiments.

Nanofibrous aerosol sample filter substrates: Design, fabrication, and characterization

The manuscript demonstrates the application of nanofibrous filtration technology to aerosol sampling, by suggesting the fabrication sequence and laboratory validation of sampling filters. Four multilayer composite filters were developed from polymers Polyc[ε]aprolactone (PCL), Cellulose acetate (CA), Poly(1-acrylonitrile) (PAN), and Poly(hexano-6-lactam) (PA6) by two modifications of electrospinning process. The layered structure provided a fibre and pore gradient from the microfibrous base layer, the mesofibrous middle layer, and the nanofibrous upper layer, acting as a 2D collection surface for aerosol particles. The sampling filters were characterized for their morphology, wettability, weight stability, filtration efficiency, and pressure drop. The fibre diameter of the nanofibrous layer ranged from 0.42 ± 0.21 μm (PCL) to 0.086 ± 0.02 μm (PA6), while pore size ranged from 2.83 ± 0.35 μm (CA) to <0.4 μm (PA6). Such a morphology allowed for reaching a consistent particle collection efficiency ranging between 99.4 and 99.9% at a particle size of 0.3 μm, and at a reasonable pressure drop, such as 0.5–2.2 kPa at a face velocity of 10 cm/s. The fabrication sequence and obtained indicate a suitability for the preparation of bespoke filtering substrates to suit a specific subsequent physical, chemical, or toxicological analysis of collected particles.

Effect of Fabric Layering Sequence and Architecture on Mechanical Properties of Clay, Jute, and Glass Fibers Reinforced Polyester Laminated Hybrid Composites

ABSTRACT Hybrid laminated composites are attracting a lot of attention these days. Indeed, mixing natural and synthetic fabrics in the same matrix completely exploits the components’ greatest properties. However, it has been proven that the use of particles such as clays increases the material performance. Hence, the aim of this study is to produce a new hybrid laminated composite system using the hand lay-up method and compression molding techniques. For this, a layering sequence of plain-woven jute fabrics and different architecture of E-Glass fibers (matt and plain-woven roving fabrics with different grammage) were selected to strengthen a polyester resin modified with a tiny amount of clays. The effects of hybridization, layering sequence, and weaving architecture were evaluated by means of mechanical tests. The dispersion and distribution of the charges in the polymeric matrix were also investigated by studying the material rheological properties. We conclude that the proposed hybridization may result in an optimal, superior, and cost-effective laminated composite that fits all the requirements of a given structure.

An investigation of the effect of structural parameters on the impact properties of sandwich-structured shock absorbers

The purpose of this study is to develop an impact absorber with a core made of sustainable textile waste as an alternative to the conventional honeycomb structure. In this case, the core structure is made of cotton fiber webs recycled from denim waste, and the outer shell is made of polypropylene plates reinforced with carbon, jute, and E-glass woven fabrics. Production of the sandwich structure is carried out using the hot press method. In addition to the fabric types and layer sequences utilized in the outer shell, the geometry of the core structure is altered, and their effect on the drop-weight impact resistance is examined. The prominent results emphasize that the use of high-performance fabrics in the outer shell facing the outer surface increases the impact resistance, and the sizes of the holes to be obtained in the core structure should be optimized in order to be effective in energy absorption. The results reveal that these developed sandwich structures can constitute a promising alternative for the automotive industry.

Fabrication and Pulse Sequences Evaluation of Iron Oxides Nanoparticles as MRI Contrast Agent

The objective of this in vivo study is to enhance the T2-weighted MRI contrast using superparamagnetic nanoparticles in liver and spleen of rabbits for biomedicine application. Superparamagnetic nanoparticles were synthesized using co-precipitation method. Superparamagnetic nanoparticles were characterized using SEM, EDX, VSM, magnetic resonance relaxation and magnetic resonance imaging (MRI). T1 and T2 relaxations were measured as function of concentration of contrast agents in liver and spleen. High relaxivity ratio r2/r1 showed the efficacy of prepared T2- weighted MRI contrast agent. Rabbits were anesthetized using xylazine and ketamine salts for medical procedure. Ketamine and xylazine were injected with the dose rate of ketamine 25-40 mg/kg and xylazine 2.5-5mg/kg intra-muscularly for veterinary anesthesia. MRI of albino rabbits was executed at 0.35 Tesla using magnetic nanoparticles. FDA approved, 0.2 ml/kg dose of contrast agents was injected in rabbits for MRI scanning. MRI axial and coronal, T1-W and T2-W images of liver and spleen were taken using Spin Echo (SE) at TE=92 and TR=551 and STIR at TE=24 and TR=5170. Spin software was used to estimate the intensity of signal in region of interest induced by magnetic contrast agent. In vivo, MRI study of magnetic contrast agents demonstrated the high T2 -weighted contrast on MRI images of liver and spleen of rabbits. This research also concludes that superparamagnetic nanoparticles may be used as MRI contrast agents for biomedicine application to see the pathology of living organs even at low tesla field.

Durability of epoxy and polyurethane bonded timber-hybrid FRP joints under hygrothermal and weathering conditions

This paper investigates the bond between laminated veneer lumber (LVL) and flax-glass hybrid fibre reinforced polymer (HFRP) with different fabric stacking sequences in the LVL-HFRP joints exposed to (1) room condition at the temperature of 20 °C and relative humidity (RH) of 57% (as reference condition), (2) hygrothermal condition (50 °C and 95% RH), and (3) weathering environment (a dry-wet-ultraviolet radiation cyclic condition). Epoxy (EP) and polyurethane (PUR) adhesives were used to manufacture the HFRP composites and bond them to the LVL as LVL-HFRP joints. The joints were tested under block shear tests to evaluate the bond behaviour. The LVL block shear specimens were also tested as the reference for the shear strength change of the LVL in the joints. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) tests were conducted to study the influence of the hygrothermal and weathering conditions on the functional groups and the glass transition temperature (Tg) of the LVL-HFRP joints. After the hygrothermal and weathering exposures, the results showed that the Tg of the EP-based and PUR-based HFRP in the LVL-HFRP joints increased due to the post-curing and the arrangement of the disordered urea groups. The average shear strength values of the LVL-HFRP joints bonded with the EP adhesive decreased by 4.6–35.2% and the reduction of the shear strength of the LVL part in the joints accounted for the decreased shear strength at the joint level. The average shear strength values of the LVL-HFRP joints bonded with the PUR adhesive decreased by 27.9–57.0% and the reduction of the shear strength at the joint level was controlled by the glass fibre layer of the PUR-based HFRP, regardless of the fabric stacking sequence in the PUR-based HFRP.