Article
Chemistry, Physical
Harri Junaedi, Tabrej Khan, Tamer A. Sebaey
Summary: This study investigates the influence of glass fiber content in rigid polyurethane foam on the mechanical properties of the sandwich structure made of carbon-fiber-reinforced polymer facing sheets. Flexural and compression tests were conducted, and the morphology of the polyurethane composite foams at different contents was observed. The results show that the mechanical properties of the sandwich structure improve with increased milled fiber loading, but then decrease after reaching a maximum at 10 wt.% loading. The density of the foam also increases with higher glass fiber loading.
Article
Engineering, Civil
Zhihao Zhu, Hai Fang, Huiyuan Shi, Chen Yang, Juan Han, Chen Chen
Summary: This study investigates the bending performance of a new type of composite sandwich panels with pultruded profile cores, and multiaxial glass fiber reinforced polymer (GFRP) facial sheets and webs between the profile cores. The influences of the position and number of fiber cloth layers on the bending properties of the sandwich panel are also studied. The failure modes, load-deflection behavior, and load-strain relationships are compared using four-point bending tests. The results show that wrapping multiaxial fiber cloth can change the brittle failure characteristics of the pultruded profiles, and that the multiaxial FRP surface and uniaxial pultruded profiles can operate effectively. The completely wrapped fiber cloth method improves the bending performance of the sandwich plate.
THIN-WALLED STRUCTURES
(2023)
Article
Mechanics
D. F. Garbin, M. L. P. Tonatto, S. C. Amico
Summary: The mechanical properties of sandwich panels with a polyurethane core and fiberglass face layers produced by continuous lamination process were studied. Tensile, compression, and shear tests were conducted on isolated face layer materials, and a nonlinear finite-element model was used to simulate the mechanical behavior of the sandwich panels in different loading conditions, showing good agreement with experimental results.
MECHANICS OF COMPOSITE MATERIALS
(2021)
Article
Materials Science, Textiles
Ting-Ting Li, Peiyao Liu, Wenna Dai, Bing-Chiuan Shiu, Hongyang Wang, Hao-Kai Peng, Jia-Horng Lin, Ching-Wen Lou
Summary: This research proposes a flexible PU foam composite with a sandwich structure to improve low velocity impact resistance. The results show significant improvement in dynamic cushion performance through the design of the interlayer structure, and they are validated through experimental and theoretical calculations.
FIBERS AND POLYMERS
(2022)
Article
Materials Science, Composites
Md Asif Rezwan Shishir, Zhaoyuan Zhang, Deng'an Cai, Xinwei Wang, Qinghua Xu
Summary: This study presents numerical and experimental analysis of free vibrations in cylindrical polymer pin-reinforced foam core sandwich composite panels with different core thicknesses. The results show that the pin-configuration with higher pin density and larger pin diameter yields higher natural frequencies. The study also demonstrates the influence of core thickness on the natural frequencies.
JOURNAL OF REINFORCED PLASTICS AND COMPOSITES
(2023)
Article
Materials Science, Composites
Alessandro Ellenberger, Milton Luiz Polli, Elaine Azevedo, Caroline Rodrigues Pereira de Paula
Summary: The combination of natural fibers and renewable source matrices can replace non-renewable materials in composites manufacturing. This study investigates the drilling process and its impact on surface damages and temperature in composites made of pinus sawdust and sisal fibers with a polyurethane foam derived from vegetable oils matrix. The results show that drilling parameters have an influence on the generation of damages, and lower cutting speed and feed rate are more suitable for drilling these types of composites.
JOURNAL OF COMPOSITE MATERIALS
(2022)
Article
Engineering, Mechanical
Jacob Marx, Afsaneh Rabiei
Summary: Steel-steel composite metal foam (SS-CMF) and composite metal foam core sandwich panels (SS-CMF-CSP) were manufactured and tested, showing that SS-CMF had higher strength compared to other metal foams due to its uniform porosities and strong bonding between the sphere wall and matrix. The SS-CMF-CSP, made by solid-state diffusion bonding stainless steel face sheets to a SS-CMF core, exhibited even higher strength than the bare SS-CMF, with the experimental results falling within the calculated upper and lower bounds for modulus of elasticity.
JOURNAL OF SANDWICH STRUCTURES & MATERIALS
(2021)
Article
Engineering, Multidisciplinary
M. Proenca, M. Garrido, J. R. Correia, M. G. Gomes
Summary: The experimental study focused on the fire resistance behavior of composite sandwich floor panels made of glass-fiber reinforced polymer faces and polyurethane foam core. Results showed that with calcium silicate board protection, the fire resistance of the sandwich panels was significantly increased, highlighting the important impact of thermal insulation on their performance.
COMPOSITES PART B-ENGINEERING
(2021)
Article
Construction & Building Technology
Changhai Peng, Yail J. Kim, Junxue Zhang
Summary: This study developed composited structural insulated panels (CSIPs) with GFRP and GFRC materials to improve thermal properties and energy savings in buildings. Simulation results using ANSYS and EnergyPlus showed that GFRP SIPs outperformed steel SIPs in terms of energy consumption and thermal performance. Reducing stud web area and using less conductive materials can effectively enhance the thermal properties of SIPs.
JOURNAL OF BUILDING ENGINEERING
(2021)
Article
Engineering, Civil
Feng Xu, Zhongshuai Liu, Rajeshkumar Selvaraj, Muhammad Ahsan
Summary: This study investigates the free vibration and bending analyses of sandwich shells made of a GFRP composite honeycomb core reinforced with graphene quantum dots (GDGQD) using a finite element (FE) formulation. Experimental tests were conducted to evaluate the mechanical characteristics of the GFRP composites with GDGQD reinforcement. The FE formulation, implemented in MATLAB, accurately predicts the vibration and bending responses of the sandwich shells, with excellent agreement compared to numerical data from the literature. The effects of various factors, such as end conditions, core-to-facesheet thickness ratio, curvature ratios, and weight percent of GDGQD, on the bending and dynamic properties of GFRP sandwich shells were also investigated.
ENGINEERING STRUCTURES
(2023)
Article
Materials Science, Composites
Selwyn Jebadurai Devaraj, Arul Jeya Kumar Arputham
Summary: In this study, the interfacial bonding between face sheets and core in sandwich composites was strengthened by introducing chopped fibers. The sandwich specimens with chopped glass fibers showed improved mechanical properties, with significantly increased flexural and compressive strength.
POLYMER COMPOSITES
(2022)
Article
Materials Science, Textiles
Qiu Chao, Apichit Maneengam, Sathiyamoorthy Margabandu, Prakhar Jindal, Pandurang Y. Patil, Guang-Wen Zheng, Rajeshkumar Selvaraj
Summary: This article investigates the dynamic characteristics of jute fiber-reinforced sandwich composite panels with periodic cores and analyzes the influencing factors. The results show that the periodic core composite sandwich panel significantly affects the structural stiffness.
JOURNAL OF NATURAL FIBERS
(2022)
Article
Mechanics
Keyu Zhu, Xitao Zheng, Cong Zhang, Niu Chen, Yagang Han, Leilei Yan, M. Quaresimin
Summary: A novel all-composite sandwich panel with channel core was proposed to enhance compressive strength and energy absorption characteristics. Experimental and numerical analysis results showed that the proposed structure exhibited better compressive strength and specific energy absorption compared to the traditional corrugated core sandwich panel. Further optimization of the structural efficiency through foam filling significantly increased the compressive strength and energy absorption.
COMPOSITE STRUCTURES
(2022)
Article
Construction & Building Technology
Hossein Malekinejadbahabadi, Amin Farrokhabadi, Gholam H. Rahimi, Amin Nazerigivi
Summary: This study investigates the effect of employing foam filled composite corrugated core on the separation between skins and core in composite sandwich structures. Experimental and numerical methods are used to compare the performance of triangular corrugated core specimens to reference specimens made of PVC foam core. The results show that using a triangular corrugated core can significantly increase the resistance to separation and flexural stiffness of the sandwich composite. The numerical model can accurately predict the maximum load before skin/core separation, with a slight difference from the experimental results.
STEEL AND COMPOSITE STRUCTURES
(2022)
Article
Materials Science, Multidisciplinary
Shou-Ning Deng, Dan Wu, Jin-Shui Yang, Hao Luo, Lan-Ling Fu, Ruediger Schmidt, Kai-Uwe Schroeder
Summary: This study proposes a damage recognition method based on the modal flexibility curvature change rate for glass fiber composite bi-directional corrugated sandwich cylindrical panels. Experimental and numerical analysis results demonstrate that this method can successfully detect the position of defects, even in complex structures with multiple damage locations.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Engineering, Mechanical
M. Garrido, R. Teixeira, J. R. Correia, L. S. Sutherland
Summary: Sandwich structures with glass-fibre reinforced polymer faces and low-density core are commonly used in civil and ocean engineering, but are prone to damage under concentrated loads due to their multilayer composition. This study experimentally investigated the quasi-static indentation and low-velocity impact behaviour of thicker civil and ocean engineering sandwich laminates, considering different types of core materials and indenters. Results showed that polyethylene terephthalate panels exhibited higher damage resistance and peak resistance values compared to polyurethane panels, while polyurethane panels showed the highest energy absorption capacity. Predictions from analytical models were reasonably accurate, but further calibration is needed, particularly regarding the effects of core material.
JOURNAL OF SANDWICH STRUCTURES & MATERIALS
(2021)
Article
Engineering, Manufacturing
J. M. Sousa, M. Garrido, J. R. Correia, S. Cabral-Fonseca
Summary: This study investigated the effects of hygrothermal ageing on pultruded GFRP profiles with two different resin systems, showing that the vinyl ester profile outperformed the unsaturated polyester profile. The most significant reduction in tensile strength occurred after immersion in water at 60 degrees C.
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
(2021)
Article
Engineering, Multidisciplinary
M. Proenca, M. Garrido, J. R. Correia, M. G. Gomes
Summary: The experimental study focused on the fire resistance behavior of composite sandwich floor panels made of glass-fiber reinforced polymer faces and polyurethane foam core. Results showed that with calcium silicate board protection, the fire resistance of the sandwich panels was significantly increased, highlighting the important impact of thermal insulation on their performance.
COMPOSITES PART B-ENGINEERING
(2021)
Article
Engineering, Chemical
Ricardo Cruz, Luis Correia, Susana Cabral-Fonseca, Jose Sena-Cruz
Summary: This study found that the preparation method of the adhesive has a significant impact on its tensile properties, particularly on the viscoelastic response and creep deformation. Under hygrothermal conditions, the adhesive exhibits linear creep behavior and can be parameterized using the Burgers equation.
INTERNATIONAL JOURNAL OF ADHESION AND ADHESIVES
(2021)
Article
Engineering, Mechanical
Pietro Mazzuca, Joao P. Firmo, Joao R. Correia, Mario Garrido
Summary: The experimental investigation showed that elevated temperature greatly affects the shear and compression properties of polyurethane foams, leading to a linear reduction in strength and modulus with temperature.
JOURNAL OF SANDWICH STRUCTURES & MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Mateus A. Hofmann, Abu T. Shahid, Mario Garrido, Maria J. Ferreira, Joao R. Correia, Joao C. Bordado
Summary: Reducing dependency on petroleum-based monomers and crosslinkers is an important goal for the plastics industry. This paper presents the development of unsaturated polyesters (UPs) and their crosslinked resins (UPRs) based on renewable resources, which exhibit similar thermal and mechanical properties to petrochemical counterparts, making them greener alternatives for high-performance applications.
ACS SUSTAINABLE CHEMISTRY & ENGINEERING
(2022)
Article
Construction & Building Technology
M. Garrido, J. M. Sousa, J. R. Correia, S. Cabral-Fonseca
Summary: This paper presents long-term prediction models for the mechanical property retention of pultruded GFRP materials, and proposes a 50-year moisture conversion factor for durability design.
CONSTRUCTION AND BUILDING MATERIALS
(2022)
Article
Polymer Science
Mateus Hofmann, Mario Garrido, Marina Machado, Joao R. Correia, Joao C. Bordado
Summary: Research on biobased thermoset resins has been overlooked compared to biobased thermoplastics. This study developed low-molecular weight macromolecules with a high bio-content, suitable for various fiber-reinforced polymer production techniques. The resulting resins exhibited comparable mechanical and thermomechanical behavior to petrochemical-based counterparts, making them greener alternatives for high-performance structural applications.
JOURNAL OF APPLIED POLYMER SCIENCE
(2022)
Article
Engineering, Civil
Ricardo Cruz, Luis Correia, Susana Cabral-Fonseca, Jose Sena-Cruz
Summary: This investigation examines the durability of the adhesive bond between near-surface-mounted carbon fiber-reinforced polymer strips and concrete. Different natural environments were considered, and the results indicate that water immersion and freeze-thaw cycles have the greatest impact on the bond performance of NSM-CFRP strips to concrete.
JOURNAL OF COMPOSITES FOR CONSTRUCTION
(2022)
Article
Chemistry, Physical
Abu T. Shahid, Mateus Hofmann, Mario Garrido, Joao R. Correia, Ines C. Rosa
Summary: This paper presents an experimental study on the wet freeze-thaw durability of a fibre-polymer composite. The results show that water immersion caused more damage to the composite than freeze-thaw cycles. The overall performance of the bio-based composite was inferior to the conventional one, mainly due to the hydrophilicity of its bio-based resin.
Article
Chemistry, Physical
Marina Machado, Mario Garrido, Joao P. Firmo, Adriana Azevedo, Joao R. Correia, Joao C. Bordado, Filipe Dourado
Summary: This paper presents an experimental study on the use of innovative bio-based CFRP laminates for structural strengthening. The study compares the properties of bio-based laminates with conventional oil-based laminates and assesses the bond behavior and structural efficacy of the bio-based laminates. The results show that the bio-based CFRP laminates have comparable properties and can be used effectively in the strengthening of RC structures.
Article
Chemistry, Multidisciplinary
Marina Machado, Mateus Hofmann, Mario Garrido, Joao R. Correia, Joao C. Bordado, Ines C. Rosa
Summary: This study investigates the effects of incorporating Lignoboost lignin into a partially bio-based vinyl ester resin. The results show that the addition of lignin enhances the resin's performance, including increased strength and glass transition temperature. This suggests the potential of lignin as a sustainable alternative to oil-based resins in fiber-reinforced polymer composites.
APPLIED SCIENCES-BASEL
(2023)
Proceedings Paper
Engineering, Civil
Mario Garrido, Joao Ramoa Correia, Md Toyob Shahid, Marina Machado
Summary: This paper assesses the design guidelines for FRP structures regarding the reduction of mechanical properties due to moisture and surveys the available test data on the effects of moisture exposure on FRP materials with E-glass fibers and unsaturated polyester or vinylester resins. The experimental data is compared with prediction models to derive a conversion factor for material degradation in high-moisture environments over a 50-year service life.
10TH INTERNATIONAL CONFERENCE ON FRP COMPOSITES IN CIVIL ENGINEERING (CICE 2020/2021)
(2022)
Proceedings Paper
Engineering, Civil
Joao Sousa, Mario Garrido, Joao Ramoa Correia, Susana Cabral-Fonseca, Md Toyob Shahid
Summary: This study investigates the effects of hygrothermal ageing on the durability and long-term performance of two commercial GFRP profiles made of different resin systems. Experimental data is used to derive analytical models for predicting the long-term effects and service life of these profiles based on the Arrhenius law.
10TH INTERNATIONAL CONFERENCE ON FRP COMPOSITES IN CIVIL ENGINEERING (CICE 2020/2021)
(2022)
Proceedings Paper
Engineering, Civil
Joao R. Correia, Thomas Keller, Mario Garrido, Mario Sa, Joao P. Firmo, Md Abu Shahid, Marina Machado
Summary: One of the main concerns in civil engineering structural applications of fibre reinforced polymer (FRP) materials is their potential reduction in stiffness and strength when exposed to elevated temperature. This paper assesses existing design guidelines for FRP structures and surveys test data available in the literature to propose a method for defining temperature conversion factors for design purposes, taking into account factors such as maximum service temperature, glass transition temperature, and mechanical property type.
10TH INTERNATIONAL CONFERENCE ON FRP COMPOSITES IN CIVIL ENGINEERING (CICE 2020/2021)
(2022)