Carbon fibers (CFs) have high specific tensile strength, high modulus, and outstanding wear resistance, and are widely used for the reinforcement of advanced composite materials. CF-reinforced thermoplastic composites have received much attention because of their easy processability and recycling convenience compared with thermosetting composites. Surface treatment of CFs is generally employed to increase the surface functional groups and interfacial adhesion between the CFs and the surrounding polymer matrix. In this review, we explore recent advances in the surface treatment of CFs and preparation of CF/thermoplastic composites. The thermal, mechanical, and electrical properties of the composites are also discussed.

Recent advances in carbon-fiber-reinforced thermoplastic composites: A review

Mode I fatigue crack arrest in tensile steel members using prestressed CFRP plates

Development of an iron-based shape memory alloy (Fe-SMA) strengthening system for steel plates

Compressive behavior of FRP-confined concrete-filled PVC tubular columns

Prestressed CFRP-strengthening and long-term wireless monitoring of an old roadway metallic bridge

In this research pull-out specimens were tested to investigate the bond behavior of superelastic NiTi (Nitinol) SMA wires to carbon fiber reinforced polymers (CFRP). A total of 45 pull-out specimens were tested monotonically up to failure. The test parameters considered include the wire diameter and embedment length. A digital image correlation (DIC) system was used to identify the onset and propagation of debonding. Based on the experimental observations two debonding mechanisms were observed: complete debonding after the onset of martensitic transformation of SMA wire, and complete debonding before the onset of wire transformation. The former mechanism predominated, while the latter mechanism governed for larger diameter wires with shorter embedment lengths. A 3-D non-linear finite element model (FEM) was developed to predict the pull-out behavior. A cohesive zone model (CZM) was used to model the interface. A parametric study was conducted using the FEM to quantify the parameters of the cohesive zone model. The results demonstrate that the proposed modeling approach can be used to characterize the bond behavior of superelastic SMA wires embedded in FRP composites.

Bond behavior of superelastic shape memory alloys to carbon fiber reinforced polymer composites

The objective of this research is to develop a self-stressing patch using a combination of shape memory alloys (SMAs) and fiber reinforced polymer (FRP) composites Prestressed carbon FRP patches are emerging as a promising alternative to traditional methods to repair cracked steel structures and civil infrastructure However, prestressing these patches typically requires heavy and complex fixtures, which is impractical in many applications This paper presents a new approach in which the prestressing force is applied by restraining the shape memory effect of NiTiNb SMA wires The wires are subsequently embedded in an FRP overlay patch This method overcomes the practical challenges associated with conventional prestressing This paper presents the conceptual development of the self-stressing patch with the support of experimental observations The bond between the SMA wires and the FRP is evaluated using pull-out tests The paper concludes with an experimental study that evaluates the patch response during activation subsequent monotonic tensile loading The results demonstrate that the self-stressing patch with NiTiNb SMA is capable of generating a significant prestressing force with minimal tool and labor requirements

https://iopscience.iop.org/article/10.1088/0964-1726/24/6/065035/pdf

Development of a self-stressing NiTiNb shape memory alloy (SMA)/fiber reinforced polymer (FRP) patch

Shape memory alloy-carbon fiber reinforced polymer system for strengthening fatigue-sensitive metallic structures

This paper presents the details of an experimental study that was conducted to characterize the fatigue behavior of a thermally-activated shape memory alloy (SMA)/carbon fiber reinforced polymer (CFRP) patch that can be used to repair cracked steel members. A total of 14 thermally-activated patches were fabricated and tested to evaluate the stability of the prestress under fatigue loading. The parameters considered in this study are the prestress level in the nickel–titanium–niobium SMA wires and the applied force range. An empirical model to predict the degradation of the prestress is also presented. The results indicate that patches for which the maximum applied loads in a fatigue cycle did not cause debonding of the SMA wires from the CFRP sustained two million loading cycles with less than 20% degradation of the prestress.

https://iopscience.iop.org/article/10.1088/0964-1726/25/1/015030/pdf

Mossab El-Tahan

Papers

Bond behavior of superelastic shape memory alloys to carbon fiber reinforced polymer composites

Development of a self-stressing NiTiNb shape memory alloy (SMA)/fiber reinforced polymer (FRP) patch

Shape memory alloy-carbon fiber reinforced polymer system for strengthening fatigue-sensitive metallic structures

Fatigue behavior of a thermally-activated NiTiNb SMA-FRP patch

Bond behavior of NiTiNb SMA wires embedded in CFRP composites