Modeling and Optimization of Abrasive Water Jet Cutting of Kevlar Fiber-Reinforced Polymer Composites

Author(s):  
Tauseef Uddin Siddiqui ◽  
Mukul Shukla

This chapter presents a detailed study of abrasive water jet (AWJ) cutting of thin and thick Kevlar fiber-reinforced polymer (FRP) composites used in transport aircraft and anti-ballistic applications. Kevlar composites are considered to be very challenging to machine using traditional techniques. Most of the research conducted in the area of AWJ cutting has been limited to single response optimization. However, in real life machining, the performance of a process/product demands multi-objective optimization (MOO). No work has been reported till now using different MOO techniques for AWJ cutting of Kevlar FRP composites. Experimental modeling of depth of cut and various design of experiments based single and multi-objective optimization studies are presented here. Statistical analysis of variance has been performed to rank the different process parameters and estimate their effects on various AWJ cut kerf quality characteristics. The studies conducted in this chapter are likely to prove beneficial to the AWJ community in performing modeling and simultaneous optimization of multiple quality characteristics.

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sıtkı Akıncıoğlu

Purpose The purpose of this study was to optimize the surface roughness (Ra), delamination damage at the hole entrance (FdT) and at the hole exit (FdB) and kerf angle (K) in the drilling of aramid fiber-reinforced polymer (AFRP) composite material using abrasive water jet (AWJ) machining. Design/methodology/approach The AFRP composite was produced by the vacuum infusion method. The drilling experiments were performed on an AWJ machine using a three-axis computerized numerical control system. Machine processing parameters were determined as water pressure (2,000, 3,000 and 4,000 bar), stand-off distance (2, 4 and 6 mm) and traverse feed rate (150, 250 and 350 mm/min). Optimization of processing parameters in the drilling experiments was carried out according to the Taguchi L27 (33) orthogonal array. In addition, gray relational analysis (GRA) was used to analyze the complex uncertainty affecting the results. Findings Results of the drilling operations demonstrated that water pressure (P) was the most effective parameter, with 65.3%, 65.2%, 49.8% and 52.1% contribution rates for Ra, FdT, FdB and K, respectively. Practical implications Reliable results have been obtained with Taguchi-based GRA while drilling AFRP composite material using AWJ. Significant results have been achieved to increase the hole quality in the drilling of AFRP composite material. Originality/value The new approach is to present more detailed analysis by using Taguchi method and multi-decision Taguchi-based gray relation analysis in AFRP composite material drilling using AWJ. Thus, time and experiment costs are saved.


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.


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