scholarly journals Short-Term Analysis of Adhesive Types and Bonding Mistakes on Bonded-in-Rod (BiR) Connections for Timber Structures

2021 ◽  
Vol 11 (6) ◽  
pp. 2665
Author(s):  
Jure Barbalić ◽  
Vlatka Rajčić ◽  
Chiara Bedon ◽  
Michal K. Budzik
Keyword(s):  
Fracture Mechanics ◽  
Design Procedure ◽  
Image Correlation ◽  
Fiber Reinforced Polymer ◽  
Special Focus ◽  
Timber Structures ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Reinforced Polymer ◽  
The Impact

Bonded-in rods (BiR) represent a structural connection type that is largely used for new timber structures and rehabilitation (repair or reinforcement) of existing structural members. The technology is based on steel / Fiber Reinforced Polymer (FRP) / Glass Fiber Reinforced Polymer (GFRP) rods bonded into predrilled holes in timber elements. The mechanical advantages of BiRs include high local force capacity, improved strength, a relatively high stiffness and the possibility of ductile behaviour. They also offer aesthetic benefits, given that rods are hidden in the cross sections of wooden members. As such, BiR connections are regarded as a solution with great potential, but still uncertain design formulations. Several research projects have dealt with BiRs, but a final definition of their mechanics and a universal design procedure is still missing. This research study explores the typical fracture mechanics modes for BiR connections. A special focus is given to the evaluation of the impact of adhesive bonds under various operational conditions (i.e., moisture content of timber). A total of 84 specimens are tested in pull-out setup, and investigated with the support of digital image correlation (DIC). The reliability of empirical equations and a newly developed analytical model in support of design, based on linear elastic fracture mechanics (LEFM), is also assessed.

Improving the impact resistance of concrete panels by glass fiber reinforced polymer sheets

2017 ◽  
Vol 8 (2) ◽  
pp. 304-320 ◽  
Author(s):  
Mohamed MA Abdel-Kader ◽  
Ahmed Fouda
Keyword(s):  
Glass Fiber ◽  
Plain Concrete ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Concrete Panels ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Polymer Sheets ◽  
The Impact

In this article, the response of 12 plain concrete specimens to an impact of hard projectiles was examined in an experimental study. The tests were planned with an aim to observe the influence of using glass fiber reinforced polymer sheets to strengthen plain concrete panels on the performance of concrete under this type of loading. The main findings show that strengthening plain concrete panels with glass fiber reinforced polymer sheets showed satisfactory performance under the impact load; the glass fiber reinforced polymer sheets can be used for strengthening or upgrading concrete structures to improve their resistance against impact. Also, the location of the glass fiber reinforced polymer sheet affects the front and rear face craters.

Influence of Basic Parameters for Fiber Reinforced Polymer Crushing Simulation

2016 ◽  
Author(s):  
Benoit Stalin ◽  
Dongyang Yang ◽  
Yong Xia ◽  
Qing Zhou
Keyword(s):  
Finite Element ◽  
Mesh Size ◽  
Fiber Reinforced Polymer ◽  
Physical Parameters ◽  
Large Element ◽  
Fiber Reinforced ◽  
Time Step ◽  
Reinforced Polymer ◽  
Simulation Results ◽  
The Impact

This article investigates the influence of finite element model features on Fiber Reinforced Polymer (FRP) crushing simulation results. The study focuses on two composite material tube models using single shell modeling approach. The chosen material model is MAT58 (*MAT_LAMINATED_COMPOSITE_FABRIC) from the commercial finite element analysis software LS-Dyna. The baseline models geometry and material parameters come from a model calibration conducted for lightweight vehicle investigation. Five parameters are investigated. The mesh size and the number of integration point (NIP) are generic and ERODS, TSIZE and SOFT are the non-physical parameters of MAT58. This analysis aims at discuss the influence of these parameters on the simulation results focusing on the initial force peak and the average crush load, regarding results realism and instabilities such as large elements deformation and abnormal peak values. Also, the impact of the number of CPUs involved in the simulation calculation is presented. Recommendations are given to set the mesh size and the NIP. TSIZE value should be selected regarding the simulation time step. On the other hand, ERODS has to be adjusted manually. Both are determinant for simulation robustness. Further studies are proposed to find out the reasons of large element deformation.

Flexural and Creep Performances of Wood Fiber Reinforced Polymer Composite

2016 ◽  
Vol 850 ◽  
pp. 91-95
Author(s):  
Yan Cao ◽  
Wei Hong Wang ◽  
Hai Long Xu ◽  
Qing Wen Wang
Keyword(s):  
Wood Fiber ◽  
Impact Resistance ◽  
Fiber Reinforced Polymer ◽  
Creep Recovery ◽  
Fiber Reinforced ◽  
Impact Performance ◽  
Reinforced Polymer ◽  
Fiber Size ◽  
Resistance Performance ◽  
The Impact

In order to optimize the size of wood fiber reinforced polymer, and extend the application field of wood fiber reinforced polymer composites and improve the safety of their use, four size of wood fiber reinforced high-density polyethylene (HDPE) composites were prepared by forming mat-compression molding. The four kinds of fibers of different size include 80-120 mesh, 40-80 mesh, 20-40 mesh and 10-20 mesh fibers. The flexural performance, impact resistance performance and 24 hours creep - 24 hours recovery of the composites are studied. Fiber of 20-40 mesh presents the best flexural and impact resistance performance. The flexural strength, the elastic modulus and the impact strength reach 26.71MPa, 2.73Gpa and 6.88 KJ/m2 respectively. The impact performance of wood fiber/HDPE composites do not change a lot, while the fiber size increases from 10 to 80 mesh. However, the composites containing 80-120 mesh fibers has minimum impact performance. The creep performance of the wood fiber/HDPE composites with 80-120 mesh is the worst. After 24h creep test, the strain of the other three groups is almost the same. Creep recovery of the composites reinforced with 40-80 mesh fiber is the worst (61.74%). The creep recovery of the other three is above seven percent. Therefore, excessively large or small fiber size proves to be negative to improve the mechanical and creep performance, and polymer composites reinforced by them are not suitable for work under long-term load.

scholarly journals MECHANICAL PROPERTIES, WATER ABSORPTION, AND FAILURE ANALYSES OF KENAF FIBER REINFORCED EPOXY MATRIX COMPOSITES

2021 ◽  
Vol 22 (2) ◽  
pp. 316-326
Author(s):  
Ikhwan Yusuff ◽  
Norshahida Sarifuddin ◽  
Siti Norbahiyah Mohamad Badari ◽  
Afifah Mohd Ali
Keyword(s):  
Water Absorption ◽  
Natural Fiber ◽  
Mechanical Tests ◽  
Fiber Content ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Kenaf Fiber ◽  
Pull Out ◽  
Reinforced Polymer ◽  
Kenaf Composites

The potential of natural fibers as one of the candidate materials in the production of fiber-reinforced polymer composites have been widely investigated. In the current study, natural fiber-reinforced polymer composite was fabricated by employing woven kenaf fiber as a reinforcing agent with epoxy resin that acts as a matrix constituent. This composite sample was fabricated using the application of the vacuum infusion method in which the content of kenaf fibers was varied from 30 vol.%, 40 vol.%, and 50 vol.%. The effects of different fiber loadings toward mechanical and physical properties as well as failure properties of kenaf composite were then evaluated. Kenaf composites were subjected to mechanical tests including tensile and flexural tests. The result shows that the highest tensile strength and modulus were attained at 76.67 MPa and 2.31 GPa, respectively with kenaf composite fabricated with 40 vol.% fiber content. Meanwhile, the highest flexural strength and modulus were recorded at 61.24 MPa and 4.20 GPa, also corresponding to kenaf composite that is loaded with 40 vol.% fibers. Fiber pull-out failure was able to be detected in fabricated kenaf composites. Meanwhile, fiber breakage resulting from flexural failure could also be observed in the kenaf composite samples. Apart from that, it was found that as more kenaf fiber was loaded in the composites, the rate of water absorption tended to increase where the highest rate of water absorption was found at 43.33%, displayed by kenaf composite with 50 vol.% of fiber content. ABSTRAK: Potensi gentian semula jadi sebagai salah satu bahan dalam penghasilan komposit polimer bertetulang gentian telah banyak dikaji. Dalam kajian terkini, komposit polimer yang diperkuat dengan gentian semula jadi dibuat dengan menggunakan serat kenaf tenunan sebagai agen penguat dan resin epoksi yang bertindak sebagai matriks. Sampel komposit ini dibuat menggunakan kaedah infusi vakum di mana kandungan serat kenaf digunakan adalah 30 vol.%, 40 vol.%, dan 50 vol.%. Kesan kandungan serat yang berbeza terhadap sifat mekanikal dan fizikal serta sifat kegagalan komposit kenaf kemudiannya dinilai. Komposit Kenaf diuji dengan ujian tegangan dan lenturan. Hasilnya menunjukkan bahawa kekuatan tegangan dan modulus tertinggi dicapai pada 76.67 MPa dan 2.31 GPa, milik komposit kenaf yang dibuat dengan kandungan serat 40 vol.%. Sementara itu, kekuatan dan modulus lenturan tertinggi dicatatkan pada 61.24 MPa dan 4.20 GPa juga milik komposit kenaf yang dimuatkan dengan serat 40% vol. Kegagalan serat terkeluar dapat dikesan pada komposit kenaf buatan. Sementara itu, kerosakan serat akibat kegagalan lenturan juga dapat dilihat pada sampel komposit kenaf. Selain itu, didapati bahawa semakin banyak serat kenaf yang dimuatkan dalam komposit, cendurung meningkatkan kadar penyerapan air di mana kadar penyerapan air tertinggi didapati pada 43.33% yang ditunjukkan oleh komposit kenaf dengan kandungan serat 50% vol.

Development of Creep Test Method for Thermoplastic Fiber-Reinforced Polymer Composite Tubes Under Pure Hoop Loading Condition

2019 ◽  
Author(s):  
Hai G. M. Doan ◽  
Hossein Ashrafizadeh ◽  
Pierre Mertiny
Keyword(s):  
Creep Behavior ◽  
Axial Loading ◽  
Test Method ◽  
Image Correlation ◽  
Fiber Reinforced Polymer ◽  
Time Dependent ◽  
Loading Conditions ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Dependent Behavior

Abstract Piping made from thermoplastic fiber reinforced polymer composites (TP-FRPCs) is receiving increasing attention in the oil and gas industry. Creep and time-dependent behavior is one of the main factors defining the service life of TP-FRPC structures. The lifetime and time-dependent behavior of TP-FRPC structures can be predicted using simulation tools, such as finite element analysis, to aid in the design optimization by modeling the long-term behavior of the material. Composite material time-dependent properties are required inputs for such models. While there is previous research available on creep testing of TP-FRPCs in laminate geometry, such tests may not enable accurate determination of the composite properties due to edge effects. On the other hand, coupons with tubular geometry not only provide improved load distribution between the fibers and matrix with minimal end effects, they also enable certain loading conditions experienced during typical piping operations such as internal pressure. In this study, a testing method to capture the creep behavior of tubular TP-FRPC specimens subjected to multi-axial loading conditions was developed. Tubular coupons were prototyped by an automated tape placement process. Strain was measure using digital image correlation technique and strain gauges. The development of the test setup forms the foundation for further testing of tubular TP-FRPC coupons at different multi-axial loading conditions. As a preliminary test, the creep behavior of a TP-FRPC tube subjected to pure hoop stress condition was evaluated using the developed testing process.

scholarly journals Creep Testing of Thermoplastic Fiber-Reinforced Polymer Composite Tubular Coupons

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4637 ◽  
Author(s):  
Hai Giang Minh Doan ◽  
Pierre Mertiny
Keyword(s):  
Creep Testing ◽  
Image Correlation ◽  
Fiber Reinforced Polymer ◽  
Ductile Material ◽  
Fiber Reinforced ◽  
Dimensional Changes ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Research Findings ◽  
Axial Compressive Stress

Thermoplastic fiber-reinforced polymer composites (TP-FRPC) are gaining popularity in industry owing to characteristics such as fast part fabrication, ductile material properties and high resistance to environmental degradation. However, TP-FRPC are prone to time-dependent deformation effects like creep under sustained loading, which can lead to significant dimensional changes and affect the safe operation of structures. Previous research in this context has focused, mainly, on testing of flat coupons. In this study, a creep testing method for TP-FRPC tubular coupons was developed. Specimens were fabricated using tape winding and subjected to well-defined loading conditions, i.e., pure hoop tensile and pure axial compressive stress. Strain gauges and digital image correlation were both employed for strain measurements and were found to be in good agreement. The evolution of strain rate, Poisson’s ratio and creep compliance were investigated. The prediction of experimental data by the Burgers model and the Findley’s power law model were explored. The research findings suggest that the developed experimental and analysis approach provides valuable information for the design of material systems and structures.

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