Load Carrying Capacity of Notched CFRP Laminates

2010 ◽  
Vol 430 ◽  
pp. 47-51
Author(s):  
H. Suzuki ◽  
S. Kinugawa ◽  
Hideki Sekine

On the basis of a micromechanical study, a method for evaluating load carrying capacity of notched CFRP laminates is developed. The damage zone at a notch tip in CFRP laminates is modeled as a fictitious crack with a cohesive stress acting on the crack surface. Then, applying the Weibull weakest link theory to the strength of surviving fiber bundles on the crack surface, we derive the relationship between the cohesive stress and the crack opening displacement, i.e., the tension-softening relation. By incorporating it in a BEM scheme, the load-displacement relationship is simulated. The simulated result for notched CPRP laminates is compared with experimental ones, and it is found that the simulated and experimental results of load carrying capacity are consistent.

2021 ◽  
pp. 136943322110105
Author(s):  
M.R. Mostakhdemin Hosseini ◽  
Salvador J.E. Dias ◽  
Joaquim A.O. Barros

The strengthening intervention of RC structures often involves already cracked concrete. To evaluate the effect of the level of damage prior to the strengthening (pre-cracks) on the behavior of the flexurally strengthened RC slabs with prestressed NSM CFRP laminates, an experimental research was carried out. Two pre-cracking levels of damage were analyzed and, for each one, three levels of prestress were tested (0%, 20% and 40%). The obtained results showed that the strengthening of damaged RC slabs with prestressed NSM CFRP laminates results in a significant increase on the load carrying capacity at serviceability limit states. Pre-cracked RC slabs strengthened with prestressed NSM CFRP laminates presented a load carrying capacity almost similar to the corresponding uncracked strengthened slabs. To determine the effective prestress level in CFRP laminates, the variation of strain over the length of the CFRP and over time was experimentally recorded. The prestress transfer length was also evaluated. The experimental results revealed that the transfer length of CFRP laminates was less than 150 mm, and the maximum value of strain loss out of transfer length (around 14%) was measured close to the cracked section of the damaged RC slabs. Significant part of strain loss in CFRP laminates occurred during 24 h after releasing the prestress load.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Fangyuan Li ◽  
Wenhao Li ◽  
Shaohui Lu ◽  
Yin Shen

For prestressed carbon fiber reinforced polymer (CFRP) tendon anchorage systems to become well established and used on a large scale, practical requirements for structure strengthening may be met by performing a relatively easy anchorage technique using prestressing CFRP laminates. From testing performed on a clip-type CFRP laminate anchorage system developed in our research group, it was revealed that this system could achieve the anchorage efficiency and the relaxation met the requirement of specification. Furthermore, the relevant indices of the anchorage system met the prestressed system standards. A test on the load-carrying capacity of a full-scale model beam demonstrated that the load-carrying capacity of the beam increased by more than 60% after it was strengthened with the anchorage system. The prestressing CFRP laminates and the bridge structure deformed and bore stress as a composite and exhibited excellent operating performance when working together.


2019 ◽  
Vol 17 (4) ◽  
pp. 782-792
Author(s):  
Prashant Rangrao Jagtap ◽  
Sachin M. Pore

Purpose This study aims to use carbon fiber-reinforced polymer (CFRP) laminates to strengthen the compression flange of structural I-beam so as to avoid local failure of compression flange and to take a load to its full capacity. Light weight beam (LB) 100 at 5.1 kg/m and LB 115 at 8.1 kg/m are used for this purpose. The compression flange of a beam is well prepared to ensure a rust-free surface so as to achieve proper bonding between the flange and fiber sheet to avoid de-bonding at the time of testing. A flange of the beam is strengthened using CFRP sheets applied to it with the help of adhesive. The beam with CFRP is cured in air for 48 h before testing. Experiments are performed in a loading frame of 100 T capacity. Results show that the load carrying capacity of the strengthened beam increased by 25-30 per cent compared to the control beam (non-strengthened), and the local failure of the compression flange due to the applied load is totally avoided. The elastic behavior of the strengthened beam is also increased compared to the non-strengthened beam, which gives a higher yield point. Design/methodology/approach Different methods exist for strengthening various structures. Use of CFRP appears to be an excellent solution. Vast research has been conducted on the use of CFRP for strengthening and retrofitting of steel structures. The load carrying capacities of steel beams can be increased by strengthening their compression flange by using CFRP and avoiding the local failure of beams at early stages. Findings The load carrying capacity of a beam strengthened with CFRP increased by 25-30 per cent compared to the non-strengthened beam. In addition, the elastic behavior of the strengthened beam is also improved. Originality/value The compression flange of the steel beam is strengthened using different layers of CFRP strips to avoid the local failure, and its deflection is observed using linear variable deformation transducer.


2005 ◽  
Vol 10 (2) ◽  
pp. 151-160 ◽  
Author(s):  
J. Kala ◽  
Z. Kala

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.


2005 ◽  
Vol 10 (1) ◽  
pp. 65-75 ◽  
Author(s):  
Z. Kala

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.


2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.


2020 ◽  
Vol 2020 (21) ◽  
pp. 146-153
Author(s):  
Anatolii Dekhtyar ◽  
◽  
Oleksandr Babkov ◽  

Sign in / Sign up

Export Citation Format

Share Document