scholarly journals Fiber-Reinforced Polymers in Freeform Structures: A Review

Buildings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 481
Author(s):  
Anastasiia Moskaleva ◽  
Alexander Safonov ◽  
Enrique Hernández-Montes

This article is a survey discussing the application of fiber-reinforced polymer composites in freeform structures and their impact on the design and shape generation process. The analysis of case studies showed that the use of FRP composites not only helps to overcome some challenges in the construction of objects with complex geometry, but also creates brand new types of structures and design approaches. On the other hand, there is a problem—although FRP materials are frequently used in construction, the shapes of structures and design methods are often traditional and are simply copied from materials such as wood, concrete, and steel. FRP composites have been applied in civil engineering for several decades, since the 1960s, as building envelopes, façade skins, load-bearing structures, and internal and external reinforcement. The article aims to analyze this accumulated experience and to explore the role of FRP materials in the design of buildings with free, complex, fluid, and organic shapes. A new classification of freeform composite structures is proposed. They are classified in this article according to the methodology applied at the conceptual design stage: structures created by using a geometric approach, a form-finding (equilibrium) approach, or a biomimetic approach. Each approach is described in its own separate section, with a thorough literature and state-of-the-art review.

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3817
Author(s):  
Roberto Scaffaro ◽  
Alberto Di Bartolo ◽  
Nadka Tz. Dintcheva

Fiber-reinforced polymers (FRPs) are low-density, high-performance composite materials, which find important applications in the automotive, aerospace, and energy industry, to only cite a few. With the increasing concerns about sustainability and environment risks, the problem of the recycling of such complex composite systems has been emerging in politics, industry, and academia. The issue is exacerbated by the increased use of FRPs in the automotive industry and by the expected decommissioning of airplanes and wind turbines amounting to thousands of metric tons of composite materials. Currently, the recycling of FRPs downcycles the entire composite to some form of reinforcement material (typically for cements) or degrades the polymer matrix to recover the fibers. Following the principles of sustainability, the reuse and recycling of the whole composite—fiber and polymer—should be promoted. In this review paper, we report on recent research works that achieve the recycling of both the fiber and matrix phase of FRP composites, with the polymer being either directly recovered or converted to value-added monomers and oligomers.


2019 ◽  
Vol 86 (3) ◽  
pp. 175-183
Author(s):  
Julian Lich ◽  
Tino Wollmann ◽  
Angelos Filippatos ◽  
Maik Gude ◽  
Robert Kuschmierz ◽  
...  

AbstractIn-situ measurements of the deformation and of the structural dynamical behavior of moving composite structures, such as rotors made of glass fiber reinforced polymers (GFRP), are necessary in order to validate newly developed simulation models. Local methods like strain gauges and fiber Bragg gratings lack spatial resolution, while contactless optical methods like image correlation or speckle interferometry suffer from noise effects in the presence of fast rigid body movements. A novel compact sensor – based on the diffraction grating method – is introduced for spatially and temporally resolved strain measurement. The use of a line camera allows the measurement of vibrations up to several tens of kHz. With a scanning movement, strain fields at submillimeter resolution can be recorded. The use of two diffraction orders and an objective lens reduces cross sensitivities to rigid body movements on the strain measurement by two to three orders of magnitude. A validation on a GFRP probe was conducted in a quasi-static tensile test with an optical extensometer up to 14500 µϵ. Furthermore, a strain measurement on a moving rotor at surface speeds up to 75 m/s was performed and the results were compared with those of strain gauges as a gold standard. The statistical standard deviation was around 10 µϵ and independent of the rotational speed.


2021 ◽  
pp. 136943322110585
Author(s):  
Seyed Mehrdad Elhamnike ◽  
Rasoul Abbaszadeh ◽  
Vahid Razavinasab ◽  
Hadi Ziaadiny

Exposure of buildings to fire is one of the unexpected events during the life of the structure. The heat from the fire can reduce the strength of structural members, and these damaged members need to be strengthened. Repair and strengthening of concrete members by fiber-reinforced polymer (FRP) composites has been one of the most popular methods in recent years and can be used in fire-damaged concrete members. In this paper, in order to provide further data and information about the behavior of post-heated circular concrete columns confined with FRP composites, 30 cylindrical concrete specimens were prepared and subjected under four exposure temperatures of 300, 500, 700, and 900. Then, specimens were repaired by carbon fiber reinforced polymer composites and tested under axial compression. Results indicate that heating causes the color change, cracks, and weight loss of concrete. Also, with the increase of heating temperature, the shape of stress–strain curve of FRP-retrofitted specimens will change. Therefore, the main parts of the stress–strain curve such as ultimate stress and strain and the elastic modulus will change. Thus, a new stress–strain model is proposed for post-heated circular concrete columns confined by FRP composites. Results indicate that the proposed model is in a good agreement with the experimental data.


2018 ◽  
Vol 52 (23) ◽  
pp. 3173-3181 ◽  
Author(s):  
Kuldeep Agarwal ◽  
Suresh K Kuchipudi ◽  
Benoit Girard ◽  
Matthew Houser

Fiber reinforced polymer composites have been around for many decades but recently their use has started to increase in multiple industries such as automotive, aerospace, and construction. The conventional composite manufacturing processes such as wet lay-up, resin transfer molding, automatic lay ups etc. suffer from a lot of practical and material issues which have limited their use. The mechanical properties of the parts produced by such processes also suffer from variation that causes problems downstream. Composites based additive manufacturing processes such as Fused Deposition Modeling and Composite Filament Fabrication are trying to remove some of the barriers to the use of composites. Additive manufacturing processes offer more design and material freedom than conventional composite manufacturing processes. This paper compares conventional composite processes for the manufacturing of Epoxy-Fiberglass fiber reinforced polymers with composite filament fabrication based Nylon-Fiberglass fiber reinforced polymers. Mechanical properties such as tensile strength, elastic modulus, and fatigue life are compared for the different processes. The effect of process parameters on these mechanical properties for the composite filament fabrication based process is also examined in this work. It is found that the composite filament fabrication based process is very versatile and the parts manufactured by this process can be used in various applications.


Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 807 ◽  
Author(s):  
Matteo Cavasin ◽  
Marco Sangermano ◽  
Barry Thomson ◽  
Stefanos Giannis

An innovative testing methodology to evaluate the effect of long-term exposure to a marine environment on Glass Fiber Reinforced Polymers (GFRPs) has been investigated and is presented in this paper. Up to one-year ageing was performed in seawater, to simulate the environment for offshore oil and gas applications. The performance of an epoxy and epoxy-based GFRP exposed at different temperatures from 25 to 80 °C was quantified. The materials were also aged in dry air, to de-couple the thermal effect from the seawater chemical action. Gravimetric testing and Dynamic Mechanical Analysis (DMA) were conducted in parallel on progressively aged specimens. The effect of specimen geometry and the anisotropic nature of diffusion are comprehensively discussed in this paper. For the quasi-infinite specimens, the results show an exponential increase in the seawater absorption rate with temperature. The methodology allowed for the prediction of the diffusivity at a temperature of 4 °C as 0.23 and 0.05 × 10−13 m2/s for the epoxy and the epoxy-based composite, respectively. The glass transition temperature reduces as sea water is absorbed, yet the sea water effects appear to be reversible upon drying.


2013 ◽  
Vol 339 ◽  
pp. 687-690 ◽  
Author(s):  
Jian Shi ◽  
Jun Kato ◽  
Li Min Bao ◽  
Kiyoshi Kemmochi

Fiber Reinforced Polymer (FRP) composites are used in many applications for their excellent strength-to-weight ratio. These properties are significant barriers for achieving the 3R concept (Recycle, Reuse, and Reduce). Inverse manufacturing is a recent technology that produces new materials and industrial goods from FRP waste based on life-cycle assessment (LCA), and it is expected to help solve the problems of 3R associated with FRP [1-. However, no effective recycling system of FRP has been established because of the cross-linked structure of thermosetting resin matrix and inorganic reinforcement fibers. To investigate the possibility of recycling and reusing both matrix and reinforcements, a project of preventing environmental deterioration was performed. In this study, a new decomposition method for recycling FRP waste by superheated steam was developed. Separation of the resin matrix and reinforcement fiber from the FRP was attempted, the FRP recycled from the separated fibers was remolded; this is called R-FRP.


Author(s):  
Shengqi Zhang ◽  
John S. Strenkowski

An Eulerian model is described that simulates orthogonal cutting of unidirectional fiber-reinforced polymer (FRP) composites. The continuous finite element method (FEM) and the discontinuous Galerkin (DG) method are combined to solve the governing equations. A progressive damage model is implemented to predict subsurface damage in the composite. A correction factor that accounts for fiber curvature is included in the model that incorporates the influence of fiber bending. It was found that fiber orientation has a dominant influence on both the cutting forces and subsurface damage. Good agreement was found between predicted cutting forces and subsurface damage and published experimental observations.


2021 ◽  
pp. 19-21
Author(s):  
Iryna Rudneva

Ukraine's construction heritage includes numerous examples of the use of metal structures, especially those used in industrial buildings and high-span structures. The use of metal structures in construction is due primarily to their mechanical properties. They are frost-resistant and can withstand temperatures down to -65 degrees, hard, durable, strong and reliable. They can also be used in areas with high seismic activity. But, as in the case of other types of structures, there is a need to restore or strengthen metal structures due to structural defects, wear of load-bearing elements, as well as to increase the load-bearing capacity. In some cases, reinforcement with fiber-reinforced polymer composites (FRP) gives a better result compared to traditional methods of reinforcement using metal


2020 ◽  
Vol 12 (4) ◽  
pp. 1557 ◽  
Author(s):  
Matthew Bell ◽  
Damon Fick ◽  
Rob Ament ◽  
Nina-Marie Lister

The proven effectiveness of highway crossing infrastructure to mitigate wildlife-vehicle collisions with large animals has made it a preferred method for increasing motorist and animal safety along road networks around the world. The crossing structures also provide safe passage for small- and medium-sized wildlife. Current methods to build these structures use concrete and steel, which often result in high costs due to the long duration of construction and the heavy machinery required to assemble the materials. Recently, engineers and architects are finding new applications of fiber-reinforced polymer (FRP) composites, due to their high strength-to-weight ratio and low life-cycle costs. This material is better suited to withstand environmental elements and the static and dynamic loads required of wildlife infrastructure. Although carbon and glass fibers along with new synthetic resins are most commonly used, current research suggests an increasing incorporation and use of bio-based and recycled materials. Since FRP bridges are corrosion resistant and hold their structural properties over time, owners of the bridge can benefit by reducing costly and time-consuming maintenance over its lifetime. Adapting FRP bridges for use as wildlife crossing structures can contribute to the long-term goals of improving motorist and passenger safety, conserving wildlife and increasing cost efficiency, while at the same time reducing plastics in landfills.


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