Application of toughened epoxy-adhesives for strengthening of fatigue-damaged steel structures

Kasper, Yann; Albiez, Matthias; Ummenhofer, Thomas; Mayer, Christoph; Meier, T.; Choffat, Fabien; Ciupack, Yvonne; Pasternak, Hartmut

doi:10.1016/j.conbuildmat.2020.121579

Cited by 32 publications

(10 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When compared to other joining techniques such as mechanical fastening and welding, adhesive bonding delivers significant advantages, such as the prospect of producing low-cost components, high strength-to-weight ratio, flexibility for joining dissimilar materials, uniform stress distribution and relatively lesser processing requirements [ 1 , 2 , 3 , 4 , 5 ]. Such advantages have made adhesive bonding application highly relevant in many industrial fields such as automotive/aeronautics [ 2 , 6 ] constructions [ 7 , 8 ] marine [ 9 , 10 ] and electronics packaging [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Moisture Absorption Behavior and Adhesion Properties of GNP/Epoxy Nanocomposite Adhesives

2021

View full text Add to dashboard Cite

In the current work, an attempt has been made to investigate the effect of Graphene Nanoplatelets (GNP) reinforcement to water absorption behavior and mechanical properties of adhesive bonding with epoxy. Epoxy adhesive with various GNP content (i.e., 0.0~2.0 wt%) was utilized to joint aluminum adherend subjected to various immersion periods (i.e., 0~60 days). Subsequently, the effect of GNP reinforcement on water uptake, water absorption rate and tensile shear strength was investigated. Depending on GNP content, two distinct behaviors in water uptake and moisture absorption rate have been observed; specimens with lower GNP content (0.5~1.0 wt%) have demonstrated increased/retention of water uptake and water absorption rate regardless of immersion period. Meanwhile, at higher GNP content (1.5~2.0 wt%), decreased water uptake and water absorption rate are generally observed. At similar GNP content, regardless of immersion periods, water immersed specimens generally demonstrate higher or retention of shear strength when compared to specimens at 0-day immersion period. These observations suggest that the relation between moisture absorption behavior and mechanical properties of GNP-reinforced adhesive with GNP content are rather complex which might be attributed to the interplay of several possible mechanisms.

show abstract

Section: Introductionmentioning

confidence: 99%

Moisture Absorption Behavior and Adhesion Properties of GNP/Epoxy Nanocomposite Adhesives

2021

View full text Add to dashboard Cite

show abstract

“…This means that even though there is a distinct transition point in almost the same levels of shear deformations but in higher values of shear stresses, the crack pattern both in the substrate and in the adhesive layer propagates simultaneously up to the debonding point of the strengthening system. The intrinsic toughened adhesive layer 370 is designed for steel substrates and especially suitable for fatigue cracking applications [4]. The crack width in the cases of concrete substrates is bigger than fatigue cracking in steel substrates.…”

Section: Resultsmentioning

confidence: 99%

“…This research examines, experimentally and analytically with finite element models (FEM), the use of toughened epoxy adhesive layers as part of strengthening schemes for RC members and has a focus on the examination of the limitation of the substrate's failure propagation due to the use of enhanced retrofitting systems. The toughened adhesives are expected to absorb more energy before debonding, especially under dynamic loads [3], [4]. The interaction with the concrete substrate to the dislocations imposed is examined with double-lap shear tests in carbon FRP (CFRPs) applied to concrete prisms.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Response of Interfaces of CFRP Sheet Strengthening Schemes Enhanced With Toughened Epoxy Adhesive Layers Applied in Corroded Concrete Substrates

Achillopoulou¹

2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

View full text Add to dashboard Cite

This paper studies the behavior of enhanced strengthening Carbon Fiber Reinforced Polymer (CFRP) strengthening schemes. The CFRP systems are bonded to concrete substrates using toughened adhesive layers to limit the failure propagation in the interface and its brittle nature. Due to the importance of the integrity of the substrate two different scenarios are examined experimentally and analytically: healthy concrete and with corrosion products leached by the corroded reinforcement. The modified shear behavior (stress, slip) of the interfaces between concrete and CFRPs was investigated with a double shear test configuration. The corrosion products leached on the external layers of the substrate affected the interface response of the strengthening scheme, resulting in lower rates of shear stresses corresponding to lower slip ratios. The analysis of the sliding and shear stress distribution along the interface has also been investigated locally by finite elements using a cohesive model (CM) to examine the propagation of failure at the interface length. Toughened adhesives limit the substrate's dislocations and shift the response of the interface from pure elastic to pseudo-ductile in distinct stages. The debonding mode (brittle or pseudo-ductile) depends heavily on the toughness of the adhesive and its tensile modulus, since the higher the modulus is, the more brittle the response becomes.

show abstract

“…ere are many studies on the fatigue performance of unwelded region strengthened by FRP material, and relative achievements have been applied in the actual project widely [11,14,15,[20][21][22]. Fewer studies have been conducted on the fatigue behavior of FRP-strengthened welded joints.…”

Section: Introductionmentioning

confidence: 99%

Fatigue Performance of CFRP‐Strengthened Rib‐to‐Diaphragm Welded Details of Orthotropic Steel Decks: Experimental and Numerical Evaluation

Song

Jiang

Wang

et al. 2022

Advances in Civil Engineering

View full text Add to dashboard Cite

Rib-to-diaphragm welded details of orthotropic steel decks (OSDs) are susceptible to fatigue cracking. To deal with such cracking problem, a strengthening method using externally bonded carbon fiber-reinforced polymer (CFRP) plates was investigated by fatigue experiment and numerical evaluation. A full-scale OSD specimen with two ribs and two diaphragms was tested to evaluate fatigue cracking behavior, as well as the stress before and after strengthening. An experimentally validated numerical model was established to confirm the optimal opportunity for CFRP strengthening. The influence of different CFRP strengthening measures were then discussed on the stress intensity factors at crack tips. It was shown that bonding of CFRP plates can significantly reduce stress of rib-to-diaphragm welded details. The best opportunity for CFRP strengthening is selected as the length of crack reaches at 25.00 mm where the amplitude of stress intensity factor is the smallest. The attachment of CFRP plates by bonding on the surface of cracked plates can reduce stress response at cracked region by more than 30%. The length of crack is of no flat growth until the total number of loading cycle after strengthening arrived at 0.8 million. Results of SIFs calculated by numerical model dropes after strengthening with reduction rate more than 35% and 18% at two crack tips and crack midpoint, respectively. Compared to the geometric dimensions of CFRP, the elastic modulus of CFRP and glue layer shows more significant influence on the fatigue performance of Rib-to-diaphragm welded details due to their stronger restraint to the propagation of crack peaks. This study provided a technical reference to the design and actual application of CFRP in the strengthening of welded details in OSDs.

show abstract

Application of toughened epoxy-adhesives for strengthening of fatigue-damaged steel structures

Cited by 32 publications

References 34 publications

Moisture Absorption Behavior and Adhesion Properties of GNP/Epoxy Nanocomposite Adhesives

Moisture Absorption Behavior and Adhesion Properties of GNP/Epoxy Nanocomposite Adhesives

Investigation of the Response of Interfaces of CFRP Sheet Strengthening Schemes Enhanced With Toughened Epoxy Adhesive Layers Applied in Corroded Concrete Substrates

Fatigue Performance of CFRP‐Strengthened Rib‐to‐Diaphragm Welded Details of Orthotropic Steel Decks: Experimental and Numerical Evaluation

Contact Info

Product

Resources

About