Glass Mat Research Articles

Effect of nickel catalyst thickness on growth of carbon nanotubes on glass nonwoven mat using thermal chemical vapor deposition method

This study aimed to explore how varying the thickness of nickel catalyst affects the synthesis of carbon nanotubes on glass mats using the thermal chemical vapor deposition (TCVD) method. Nickel served as the catalyst, with acetylene as the hydrocarbon source and argon as the carrier gas. Initially, different thicknesses of nickel catalyst were applied to the glass mat via plasma-enhanced chemical vapor deposition (PECVD). Subsequently, these samples underwent TCVD plasma treatment. Electrical resistance measurements were conducted, and scanning electron microscopy (SEM), Raman spectroscopy, and transmission electron microscopy (TEM) were employed to analyze the presence, surface morphology, and quality of the nanotubes. The research revealed that the thickness of the nickel catalyst significantly influences the nanotube synthesis process on glass mat substrates. An optimal thickness of nickel catalyst yielded a glass mat with an electrical resistance of 2 Ω per unit area post-TCVD treatment.

Crash analysis of glass mat thermoplastic (GF/PA6) tubes considering splaying failure mode and energy absorption

Glass mat thermoplastic tubes are potential materials for improving crashworthiness owing to their excellent crash energy absorption capability due to their splaying failure mode of glass mat thermoplastic tubes, which must be considered in the crash analysis to accurately predict their crash performance. This study investigates the crash analysis of glass-mat thermoplastic composite tubes to realize the splaying failure mode and crash energy absorption capability. We evaluated the mechanical properties and fracture toughness of advanced glass mat thermoplastics, termed multi-layered hybrid mats, and employed the result in a 3D Hashin-type continuum damage model implemented with a user material subroutine. For the crash analysis of glass mat thermoplastic tubes, a three-dimensional finite element (FE) model, including cohesive elements in the middle layer of the tube to simulate the splaying failure mode, was constructed. In addition, in the process of the efficient FE modeling of the crash tube, the fracture toughness correction factor was proposed and optimized to calibrate the energy absorption in conjunction with crash test results, as interlaminar fracture modeling causes a difference in energy absorption between the actual test and simulation. As a result, the proposed crash analysis predicted the energy absorption capacity and a splaying failure mode of glass-mat thermoplastic tubes, demonstrating strong concordance with experimental results.

Optimization, Design, and Manufacturing of New Steel-FRP Automotive Fuel Cell Medium Pressure Plate Using Compression Molding

In this work, a new plastic-intensive medium-pressure plate (MPP), which is part of a fuel-cell system, has been developed together with a steel plate meeting all mechanical and chemical requirements. This newly developed MPP had to achieve the objective of saving weight and package space. The use of compression molding as a manufacturing technique facilitated the use of glass mat thermoplastics (GMT) which has higher E-modules and strength compared to most of the injection molded materials. A steel plate was placed as an insert to help achieve the stiffness requirements. For the development, the existing MPP was benchmarked for its structural capabilities and its underlying functional features. Four different FRP materials were investigated in terms of their chemical and mechanical properties. PP-GMT material, which has both high mechanical performance and resistance against chemicals in the fuel cell fluid, had been chosen. Using the properties of the chosen PP-GMT material, topology optimization was carried out based on the quasi-static load case and manufacturing constraints, which gave a load-conforming rib structure. The obtained rib structure was utilized to develop the final MPP with adherence to the functional requirements of MPP. The developed plastic-intensive MPP exhibits a 3-in-1 component feature with a 55% reduction in package space and an 8% weight reduction. The MPP was virtually analyzed for its mechanical strength and compared with the existing benchmark values. Finally, a press tool was conceptualized and manufactured to fabricate the new plastic-intensive MPP, which was tested in a rig and validated in the FE model.

Load Bearing Capacity and Failure Analysis of Fibrous Plaster Wads

ABSTRACT Fibrous plaster is a culturally significant material used in high-status buildings from the late nineteenth century. Fibrous plaster ceilings are typically suspended using load-bearing fibrous plaster wads, which are attached to roof structure components. Understanding the behaviour of wads is highly significant, with important safety implications emphasised by the partial collapse of the Apollo Theatre ceiling in 2013. This study demonstrates an original, innovative test method for fibrous plaster wads that enables quantification of load capacities, with manufactured specimens representative of historic in situ wads. The methodology is rigorously evaluated for traditional and alternative wad designs, reinforced with hessian scrim or continuous fibre glass (CFG) mat, with and without steel wires in looped (untwisted) or looped-twisted configurations. Tensile tests generated load-displacement characteristics and determined failure modes including cracking of plaster, deformation and tearing of fibrous reinforcement, and if present, plastic failure of a wire. Results demonstrate that hessian performs better than CFG in axial tension and inclusion of a wire increases tensile load capacity and ductility. An industry standard repair wad with hessian and looped-twisted wire can typically support 3 kN. Looped wire performed better in isolation than looped-twisted wire, with higher peak loads and greater ductility, while looped-twisted wire carried a greater load as part of a fibrous plaster composite wad. The test methodology and findings have revealed new insights into the mechanical behaviour of wads which will inform commercial practice and conservation of historic buildings, preserving important heritage and promoting safe longevity.

Reinforcement of thin hot-stamped components by fiber reinforced plastic structures with optimized fatigue strength properties

Multi-material structures in the automotive industry hold great potential for lightweight design, body construction, and functionalization due to their favorable mechanical properties and reduced structural weight. The combination of metal and plastic, in particular, is commonly used to enhance the overall properties of the end product when compared to single-material structures.This paper describes a process development with a hot-stamping and an extrusion tool. By means of this tool, a thermally assisted extrusion process can be used to join GMT (Glass Mat reinforced Thermoplastics) and 22MnB5 steel in a single process step. Through adhesion, the GMT adheres to the rough surface of the AlSi(aluminum-silicon)-coated 22MnB5. Test components were manufactured and through static tests the influence of process parameters was evaluated. Assuming that the parameters determined for the reference component are already sufficient for a design in the vehicle, the reduction of the steel thickness of the structure from 1.5 mm to 1.2 mm can be recommended on the basis of the results obtained. This is accompanied by a reduction in the mass of the test structure used while maintaining or improving its dynamic and static properties. Further weight savings appear possible through further component and process optimization.

Experimental and numerical analysis of the behavior of rehabilitated aluminum structures using chopped strand mat GFRP composite patches

PurposeThis paper comprehensively addresses the influence of chopped strand mat glass fiber-reinforced polymer (GFRP) patch configurations such as geometry, dimensions, position and the number of layers of patches, whether a single or double patch is used and how well debonding the area under the patch improves the strength of the cracked aluminum plates with different crack lengths.Design/methodology/approachSingle-edge cracked aluminum specimens of 150 mm in length and 50 mm in width were tested using the tensile test. The cracked aluminum specimens were then repaired using GFRP patches with various configurations. A three-dimensional (3D) finite element method (FEM) was adopted to simulate the repaired cracked aluminum plates using composite patches to obtain the stress intensity factor (SIF). The numerical modeling and validation of ABAQUS software and the contour integral method for SIF calculations provide a valuable tool for further investigation and design optimization.FindingsThe width of the GFRP patches affected the efficiency of the rehabilitated cracked aluminum plate. Increasing patch width WP from 5 mm to 15 mm increases the peak load by 9.7 and 17.5%, respectively, if compared with the specimen without the patch. The efficiency of the GFRP patch in reducing the SIF increased as the number of layers increased, i.e. the maximum load was enhanced by 5%.Originality/valueThis study assessed repairing metallic structures using the chopped strand mat GFRP. Furthermore, it demonstrated the superiority of rectangular patches over semicircular ones, along with the benefit of using double patches for out-of-plane bending prevention and it emphasizes the detrimental effect of defects in the bonding area between the patch and the cracked component. This underlines the importance of proper surface preparation and bonding techniques for successful repair.Graphical abstract

Effect of absorptive glass mat soaking method on electrical properties of VRLA batteries

The valve-regulated lead-acid (VRLA) battery with an absorbent glass mat has an important part in the global market for chemical power sources. This type of cell is used for both automotive SLI applications and stationary energy storage. The absorptive glass mat (AGM) is a key component in the VRLA battery, which co-determines the electrical properties of the system. For this type of lead-acid battery one of the most important stages of its production is the process of filling the cells with electrolyte and soaking absorptive glass mat before formation. Due to glass mat properties and overall high compression of plate group, this stage of production is difficult to carry out properly, especially in a short period of time. Therefore, to reduce the time, vacuum fillers are used. However, the problems of homogeneous filling of the glass mats cause that the process is often carried out in two steps. This article presents the effect of different electrolyte filling techniques on the 12V VRLA AGM battery's properties. Chemical and electrochemical experiments showed that the implementation of the one-step electrolyte filling process did not cause a decrease in the battery performance, while also reducing the time by about 26.7% compared to the method used previously.

Operando analysis of the positive active mass of lead batteries by neutron diffraction

We have analysed, through neutron diffraction experiments with the volume-gauge technique, the operando performance of lead cells composed of industrial positive and negative electrodes, previously tank formed in the manufacturing plant. The cells, 6.7 cm × 11.5 cm in surface, comprised a 3.4 mm thick positive electrode sandwiched between two 2.3 mm thick negative electrodes. The electrolyte was sulphuric acid diluted in water, both deuterated, and the separators were industrial grade absorptive glass mat (AGM). The experiments, carried out using the VULCAN instrument at the Oak Ridge National Laboratory (TN, USA), showed the evolution of α-PbO2, β-PbO2 and PbSO4 phases in the positive active mass during charge/discharge cycling, comparing the behaviour of fresh and cycled cells. No evidence of PbSO4 phase in fully charged plates or PbO in any state of charge were found above 1% by weight. Significant inhomogeneity of phase distribution and transition rates inside the positive electrode was observed. The experiments allowed estimation of the energy efficiency by comparing the external energy provided to the cell with the energy stored in the PbSO4 to PbO2 transformations.

Experimental, numerical and analytical study on axial compression buckling of chopped glass fibre-reinforced polymer cylindrical shells

A series of experiments were carried out to investigate the buckling response of chopped strand mat glass fibre-reinforced polyester (CSM-GFRP) cylindrical shells when subjected to axial compression load. Finite element modelling by using ABAQUS was performed to verify the experimental results, then a parametric study was conducted to investigate the effect of wall thickness, shell height, radius, young’s modulus, fibre volume fraction, and geometric imperfections on the buckling load of the CSM-GFRP cylindrical shells. The findings revealed that the buckling load was decreased with increasing the radius-to-wall thickness ratio (r/t) and increasing the value of the imperfection amplitude-to-wall thickness ratio, Additionally the results indicated that the buckling load increased with increasing the fibre volume fraction. Finally, an equation was proposed to predict the buckling load of the CSM-GFRP cylindrical shells using nonlinear regression analysis.

Experimental and predictive analysis of the molding behavior of a PA6 glass mat thermoplastic (GMT)

Experimental and predictive analysis of the molding behavior of a PA6 glass mat thermoplastic (GMT)

Rheological characterization and macroscopic modeling and simulation of the molding process of a PA6 Glass Mat Thermoplastic (GMT)

This study targets the characterization and modeling of GMT press molding. The targeted material is TEPEX® flowcore, a long glass fiber mat reinforced polyamide (PA6/GF) manufactured by Lanxess. Press molding of flowcore comprises the sequential stages of material forming and material flow, including challenges like local wrinkling and incomplete mold filling, respectively. Therefore, a sequential modeling approach using a Lagrangian and an Eulerian discretization is pursued. Rheological characterization using rheometer setups and in-mold viscosity measurements reveals a significant anisotropy of viscosity resulting from the predominantly in-plane fiber alignment. Anisotropy of viscosity is successfully modeled and parameterized, enabling a unified material modeling for material forming and material flow. Good predictions are observed for both wrinkling and flow. In summary, molding simulation results reveal that the isotropic modeling of viscosity is sufficient for flow simulation, whereas considering the anisotropic viscosity is essential for the accurate prediction of material forming.

The Reinforcement Effect of Nanoclay on the Damping Characteristics of Hybrid Laminated Composites

The Hybrid Nanocomposite (HNC) laminates are processed by reinforcing the chopped strand mat glass fiber and organically modified montmorillonite clay (OMT) in the polyester matrix. The different percentage by weight (1, 2, 3, and 5% ) of OMT are mixed by high speed shear mixer into the polyester matrix and then the HNC laminates are fabricated by introducing pre-mixed polyester-clay into the CSM by hand lay-up technique. A tensile test result reveals that nanoclay in polyester matrix significantly improves the tensile modulus and strength of HNC. The results also indicate that increasing the amount of nanoclay beyond 2% by weight reduces the mechanical properties but surpassing the basic glass fiber filled system. The reinforcing effect of clay enhances the flexural modulus and strength. Considerable improvement in impact energy absorption is seen from the impact test. Dynamic mechanical analysis shows that incorporation of nanoclay improves the storage modulus and Loss tangent of HNC. Free vibration tests and logarithmic decrement methods are used to predict the dynamic characteristics such as natural frequency, and damping factor for the first four modes of different clay concentrations. Dynamic results show that second phase nanoscale dispersion between the matrix and E-glass fiber significantly enhances the internal damping of hybrid composites.

Computed tomography investigations of 3D aluminum-GMT hybrid profiles manufactured by compression molding

The main work issue is to optimize the manufacturing of hybrid profiles bearing loads defined by the automotive application, based on the monitoring of the production quality using computed tomography (CT). This offers an efficient, accurate and non-destructive inspection of the products in terms of time and costs in order to prove the production quality. The investigated parts consisted of glass mat reinforced thermoplastic (GMT) 3D structures covered by aluminum straps (AA5754) with different thicknesses. They were manufactured at varied process temperatures by compression molding. The profiles quality was evaluated by CT, where the designed and actual dimensions were compared and the porosity and the fiber distribution inside the profiles were examined. In a next step, quasi-static three point bending tests were carried out on the produced profiles in order to evaluate the impact of the production effects on the mechanical behavior. First CT results showed an inhomogeneous distribution of the fibers in the matrix especially for the profiles fabricated at lower tool temperature. Pores were also found in the areas with low concentration of fibers. After bending, the cracks tended to propagate along the fiber orientation. Consequently, the main failure mechanisms consisted in inter fiber fracture and delamination of the aluminum strap.

Hybrid wood-glass and wood-jute-glass laminates manufactured by vacuum infusion

Hybrid unidirectional wood-jute laminates manufactured by the vacuum infusion processing (VIP) may present some limitations, including high incidence of delamination failures, low interfacial adhesive strength and low transverse mechanical strength. This study proposes a way to overcome these issues by manufacturing wood-glass and wood-jute-glass laminates by VIP. Pine wood veneers, jute nonwoven fabrics, glass mats and a polyester resin were employed in the here studied five-layer laminates. Apparent density, compressive, longitudinal flexural, transverse flexural, short beam testing, morphology and water absorption were the characterization analyses. As expected, the higher the number of glass layers, the higher the apparent density (up to 30%), the thinner the laminates, the closer the longitudinal and transverse mechanical properties and the smaller the water uptake levels. Based on increases of up to 70% in short beam strength, the wood-glass interface bonding was more qualified than the wood-jute one. Among all laminates, those ones with glass mats as faces showed higher longitudinal and transverse flexural properties. Besides, the higher the number of jute layers, the higher the void content.

Use of 3D Optical Techniques in the Analysis of the Effect of Adding Rubber Recyclate to the Matrix on Selected Strength Parameters of Epoxy–Glass Composites

Abstract The article presents a method of modifying the strength properties of epoxy–glass composite by changing the percentage composition of the matrix by the addition of rubber recyclate. Taking into account environmental protection and economic conditions in the process of recycling and utilisation of waste, it is advisable to look for applications of non-degradable waste materials. Based on epoxy resin, a glass mat with a random direction of fibres and rubber recyclate, a test material with different percentage compositions was produced. Samples from the manufactured materials were subjected to a static tensile test on a ZwickRoell testing machine using the ARAMIS SRX measuring system. In addition, CT (computerized tomography) scans of the inside of the samples were made using a ZEISS METROTOM 6 Scout tomograph, and observations of the internal structures were made using a scanning electron microscope. The use of optical and microscopic techniques enabled the precise determination of strength parameters of the examined composites and the analysis of the behaviour of samples under load. The analysis of deformations over time in the examined samples showed a beneficial effect of the addition of rubber recyclate on the elastic properties of the examined composites.

Analysis of GMT Composite Material-based Building Formwork

GMT (Glass Mat Reinforced Thermoplastics) is a new type of composite material made of mica and glass fiber blended into a polypropylene resin substrate, and it is durable, lightweight, high-strength, translucent and easy to install, what’s more, it can be recycled and reused to meet the needs of energy conservation and environmental protection. It is one of the mainstream building formwork materials at present. This paper analyzes and summarizes the performance of the new formwork of GMT, compares it with the traditional mainstream template, studies the problems existing in the development of GMT formwork and conducts corresponding analysis. It is pointed out that through continuous improvement of GMT formwork construction technology and the entire formwork system, its technical advantages can be fully utilized and maintained, in order to provide reference for the further development of GMT new building formwork.

Optimized Strength of Chopped Strand Mat Glass Fiber-Reinforced Polyester Laminates with Single-Edge Notch under the Effects of Notch Shape/Size and Strain Rate

Optimized Strength of Chopped Strand Mat Glass Fiber-Reinforced Polyester Laminates with Single-Edge Notch under the Effects of Notch Shape/Size and Strain Rate

Post-blast residual static capacity of retrofitted reinforced concrete slabs

Laboratory static bending tests were carried out to determine post-blast residual load-bearing capacities of retrofitted and un-retrofitted RC slabs. Three different retrofit systems were previously devised to strengthen RC slabs on potential blast-induced damage. The retrofit systems consisted of impregnating epoxy resin with (1) one layer of glass woven fabric and (2) one and (3) two layers of chopped strand glass mat. The contribution to strength, stiffness, energy absorption and damage reduction of devised retrofit systems was evaluated during testing by measured deformations, displacements, and force capacities. The presented results indicate that all applied retrofit systems provided some blast mitigation level by enhancing RC slabs' residual strength and stiffness capacity. However, the retrofit system consisted of two layers of chopped-strand glass mat made the highest contribution to strength preservation.

Fibre-Reinforced Polymers and Steel for the Reinforcement of Wooden Elements-Experimental and Numerical Analysis.

These elements are innovative and of interest to many researchers for the reinforcement of wooden elements. For the reinforced beam elements, the effect of the reinforcement factor, FRP and steel elastic modulus or FRP and steel arrangement of the reinforcement on the performance of the flexural elements was determined, followed by reading the load-displacement diagram of the reinforced beam elements. The finite element model was then developed and verified with the experimental results, which was mainly related to the fact that the general theory took into account the typical tensile failure mode, which can be used to predict the flexural strength of reinforced timber beams. From the tests, it was determined that reinforced timber beam elements had relatively ductile flexural strengths up to brittle tension for unreinforced elements. As for the reinforcements of FRP, the highest increase in load-bearing capacity was for carbon mats at 52.47%, with a reinforcement grade of 0.43%, while the lowest was for glass mats at 16.62% with a reinforcement grade of 0.22%. Basalt bars achieved the highest stiffness, followed by glass mats. Taking into account all the reinforcements used, the highest stiffness was demonstrated by the tests of the effectiveness of the reinforcement using 3 mm thick steel plates. For this configuration with a reinforcement percentage of 10%, this increase in load capacity was 79.48% and stiffness was 31.08%. The difference between the experimental and numerical results was within 3.62-27.36%, respectively.

Evaluation of Mechanical Behaviour of Multiwalled Nanotubes Reinforcement Particles in Jute-Glass Fibres Hybrid Composites

Fibre-reinforced polymers (FRPs) are composite materials of plastics reinforced with fibres. Cars, sea, aeronautics, and foundation projects progressively utilize fibre-reinforced polymers. This study aims to study the effect of adding multiwalled nanotubes fillers into the hybridized jute-glass FRP composites and their relative properties. This study uses multiwalled nanotubes (MWCNTs), and particles-hybrid jute-glass composites containing jute fibre chopped layer mats, woven glass mats, epoxy resin, and multiwalled nanotubes fillers were created using the hand layup method. After adding multiwalled nanotubes fillers in various weight proportions, the mechanical behaviours of fibre-reinforced polymers were analysed. The mechanical behaviours of laminated composites were tested using the ASTM standard; the following properties are tensile, flexural, and impact strength. The multiwalled nanotubes with 6% wt. attained the maximum mechanical properties compared to the 2 and 4 wt. % of MWCNTs. The E-based specimen contributes the most to the different types of specimens, with a contribution of 24.21% for tensile, 25.03% for flexural, and 24.56% for impact. The microstructures of hybrid composites were studied using a scanning electron microscope.