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Seismic strengthening of rigid steel frame with CFRP

Tafsirojjaman T., Fawzia S., Thambiratnam D., Zhao X. L.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 2

334--347

EN

Steel frames are a very popular choice in building construction and are used extensively in high seismic risk regions across the world. These existing and future constructed steel frames may need to undergo seismic strengthening to mitigate the high collapse risk during possible earthquakes in the future. In this study a finite element (FE) model was developed, analysed and the results compared with the present self-performed experimental study using shake table tests of steel frames strengthened with externally bonded carbon fibre reinforced polymers (CFRP) composites to validate the modelling techniques. The validated modelling technique are then used for a comprehensive parametric study on the effects of frequency of excitation, maximum acceleration, modulus of CFRP, thickness of CFRP, number of CFRP layers and adhesive type on the seismic response of the frame structure. The results indicate that externally bonded CFRP strengthening is very effective for seismic strengthening of steel frames. The CFRP strengthening technique reduced the lateral deflection by improving the stiffness and energy absorption capacity of the steel frames.

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Carbon fibre reinforced wheel for fuel ultra-efficient vehicle

Wilczynski A., Bartczak M., Siczek K., Kubiak P.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

1419--1437

EN

Due to municipal policies that are about to be legislated in many cities around the world, it may occur that habitants will be forced to commute in ultralight urban low-consuming cars. This paper covers the research concerning the innovative design, manufacturing method and the test of the wheel for such a vehicle. The design guidelines were as follows: elevated rigidity and durability, reduced weight and ease to adapt different types of hubs and powertrains. This was achieved by determining the forces acting on the wheel, examination of the characteristics of the possible materials and performing static finite element analysis simulations that were aimed to reveal stresses distribution and presumable failure points. Afterwards, the carbon fiber reinforced polymer disc wheel was manufactured and tested to compare the empirical deformations with the results of the simulations. The results proved that this type of wheel can be successfully used in ultralight passenger vehicle. The predicted weight reduction of such a wheel, in comparison to the wheels available on the market, may be about 40% due to using carbon fibre reinforced polymer and new, innovative solution - the magnesium hub, instead of aluminum, that is known to damp the vibration more efficiently and is easier to create a strong bond with the wheel.

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Propagation of cracks in reinforced concrete beams cracked and repaired by composite materials

Benarbia D., Benguediab M.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 3

591--601

EN

Strengthening and repairing existing reinforced concrete structures is often more economical and sustainable than rebuilding them. Today the most commonly used techniques based on reparation by externally bonded Carbon Fiber Reinforced Polymers (CFRP). However, bonding concrete beams, particularly damaged beams, suffer from the pre-existing of open cracks at the bottom face of the beams. This paper presents an investigation by finite element method using the general purpose FE software Abaqus to study the flexural behavior of initially damaged concrete beams repaired with FRP plates. In this study, it is aimed to simulate the phenomenon of propagations of cracks where the beam is initially loaded to introduce damage, then, after bonding the FRP plates. The linear elastic fracture mechanics (LEFM) approach is adopted to pursue the stress intensity factor’s evolution in 3-points bending before and after reparation of RC beams. Many parameters were taken account, such us the thickness of the adhesive layer and reinforcing plate, the stiffness, and young’s modulus. Results were identified and discussed.