An Experimental Study of Drilling Parameters Effect on Composite Carbon/Epoxy Damage

2013 ◽  
Vol 554-557 ◽  
pp. 2038-2046 ◽  
Author(s):  
Yosra Turki ◽  
Malek Habak ◽  
Raphael Velasco ◽  
Jean Noel Laurent ◽  
Pascal Vantomme
Keyword(s):  
Experimental Study ◽  
Composite Materials ◽  
Epoxy Composite ◽  
Cutting Speed ◽  
Experimental Results ◽  
Delamination Factor ◽  
Drilling Parameters ◽  
Thrust Forces ◽  
Composite Carbon ◽  
Different Parts

The main purpose of composite materials drilling is the need to put together different parts of a structure, in aeronautics for example. The objective of this study is to experimentally analyze the influence of drilling on a carbon/epoxy composite. Three geometries of drill, a range of cutting speed and feed have been tested. Thrust forces and moments have been recorded during machining and macroscopic analyses have been conducted to examine outside and inside surfaces of the holes. Damages have been also quantified using delamination factor Fd. Experimental results have shown significant influences of feed and drill geometry on delamination and the best results have been obtained using a spur drill.

Defect evaluation of the honeycomb structures formed during the drilling process

2019 ◽  
Vol 29 (3) ◽  
pp. 454-466
Author(s):  
P Ghabezi ◽  
M Farahani ◽  
A Shahmirzaloo ◽  
H Ghorbani ◽  
NM Harrison
Keyword(s):  
Feed Rate ◽  
Cutting Speed ◽  
Drilling Process ◽  
Delamination Factor ◽  
Drilling Parameters ◽  
Principal Factors ◽  
Novel Method ◽  
Full Factorial Experimental Design ◽  
Tool Diameter ◽  
Full Factorial

In this paper, a comprehensive experimental investigation was carried out to precisely characterize the delamination and uncut fiber in the drilling process. A digital imaging procedure was developed in order to calculate the damage resulted from the drilling process. A novel method is proposed in this article based on image intensity to verify the obtained results. A full factorial experimental design was performed to evaluate the importance of the drilling parameters. Among other process parameters, feed rate, cutting speed, and tool diameter are the principal factors responsible for the delamination damage size during the drilling. The drilling process was assessed based on two proposed incurred damage factors, specifically the delamination factor and uncut fiber factor. Experimental results demonstrated that the feed rate was the paramount parameter for both delamination and uncut fiber factors. It was observed that both factors increased with an increase in the feed rate. Additionally, by increasing the tool diameter, the delamination and uncut fiber factors significantly increase. The effects of the cutting speed on damage factors were not linear. The minimum delamination factor and uncut fiber factor were obtained at the cutting speed of 1500 and 2500 r/min, respectively.

A study on mechanical properties after bonded repair of sandwich composite materials

2020 ◽  
Vol 34 (07n09) ◽  
pp. 2040033 ◽  
Author(s):  
Sunghoon Kim ◽  
Jongrok Ha ◽  
Seongwon Yoon ◽  
Myunghyun Kim
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Composite Materials ◽  
Recovery Rate ◽  
Fatigue Tests ◽  
Experimental Results ◽  
Sandwich Composite ◽  
Bonded Repair ◽  
Patch Repairs ◽  
The Difference

In this paper, an experimental study was conducted to determine the efficiency of repair methods for sandwich composites used as hull materials in leisure ships. The method was applied to external, scarf, and step patch repairs using an epoxy bond. The load was described in terms of the hogging and sagging moments applied to the hull by waves. Static and fatigue tests were performed to derive the recovery rate of repaired specimens. The experimental results indicated that the recovery rate of specimens with the scarf patch was the highest at 91.80% when the hogging moment was applied. However, the difference in the recovery rate between hogging and sagging moments was the lowest for specimens with the step patch, and the recovery rate was high at 89.96% and 85.15%, respectively.

Refined delamination characterization for composite laminates using digital means

2011 ◽  
Vol 46 (13) ◽  
pp. 1535-1547
Author(s):  
VA Nagarajan ◽  
S Sundaram ◽  
K Thyagarajan ◽  
J Selwin Rajadurai ◽  
TPD Rajan
Keyword(s):  
Composite Materials ◽  
Composite Laminates ◽  
Experimental Results ◽  
Damage Level ◽  
Delamination Factor

Drilling is most widely applied to composite materials; nevertheless, the damage induced by this operation on composite materials may reduce drastically the component performance. In order to establish the damage level, delamination is measured quantitatively using digital means. A comparison between the conventional ( FD) and adjusted ( FDA) delamination factor is presented. In order to quantify the delamination effectively, ‘a refined delamination factor ( FDR)’ is proposed. The accuracy of the proposed criteria is validated using experimental results.

scholarly journals Evaluation of Factors Affecting Delamination, Tensile Strength, Thrust Force and Surface Roughness in Drilling of GFRP

2021 ◽  
Author(s):  
Erol KILICKAP ◽  
Yahya Hışman Celik ◽  
Burak Yenigun
Keyword(s):  
Surface Roughness ◽  
Tensile Strength ◽  
Feed Rate ◽  
Thrust Force ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Gfrp Composites ◽  
Glass Fiber Reinforced Plastic ◽  
Delamination Factor ◽  
Drilling Parameters

Abstract The drilling operation of glass fiber reinforced plastic (GFRP) composites has gained importance because they are used as structural components in many industries such as aerospace and aviation. In the drilling of GFRP composites, some problems such as deformation and fiber breakage occur. Thrust force, delamination, surface quality and cutting temperature are affected by drilling parameters and woven types in the drilling of GFRP composites. At the same time, delamination also affects tensile strength. In this study, the effects of drilling parameters and woven types of GFRP composites on thrust force, surface roughness, delamination factor, and cutting temperature were examined in the drilling of GFRP composites produced in unidirectional (UD), ± 45º and 0°/90º woven types. The effects of drilling parameters and the delamination factor on the tensile strength of the drilled specimen were also investigated. The result of this study indicated that thrust force, delamination factor, and surface roughness increased with increasing cutting speed and feed rate. An increase in feed rate decreased the cutting temperature while an increase in cutting speed increased the cutting temperature. Also, it was found that the delamination had a critical influence on the tensile strength of the GFRP composites.

EVALUATION OF THE EFFECTS OF DRILLING PARAMETERS, TOOL GEOMETRY AND CORE MATERIAL THICKNESS ON THRUST FORCE AND DELAMINATION IN THE DRILLING OF SANDWICH COMPOSITES

2021 ◽  
pp. 2150112
Author(s):  
ERGÜN EKİCİ ◽  
GÜLTEKİN UZUN ◽  
SEDAT ALTAŞ
Keyword(s):  
Feed Rate ◽  
Thrust Force ◽  
Cutting Speed ◽  
Fiber Formation ◽  
Core Material ◽  
Tool Geometry ◽  
Sandwich Composites ◽  
Material Thickness ◽  
Delamination Factor ◽  
Drilling Parameters

This study examined the effects of drilling parameters, tool geometry, and core material thickness (CMT) on thrust force and the delamination factor in the drilling of sandwich composites. Aluminum honeycomb (10 and 15[Formula: see text]mm in thickness) was used as the core material, with carbon fiber-reinforced polymer (CFRP) as the top and bottom surfaces. In the drilling experiments, three different cutting speeds (60, 78 and 100[Formula: see text]m/min) and two different feed rates (0.05 and 0.075[Formula: see text]mm/rev) were used. Drills having a diameter of 6.35[Formula: see text]mm and three different geometries (candlestick drills, twist drills and dagger drills) were used in the experiments. At the end of the experiments, thrust force was seen to increase with increased feed rate and CMT. Increased cutting speed generally decreased the thrust forces and the minimum thrust force was achieved with the 10 mm thick core material, 0.05[Formula: see text]mm/rev feed rate and 100[Formula: see text]m/min cutting speed using the dagger drill. The delamination factor at the entrance area was very low when drilling the sandwich composites and there was no significant difference based on drilling parameters, tool geometry, or CMT. Tool geometry was the main effective factor on exit delamination, and the highest delamination occurred with the use of the candlestick drill. Although increased feed rate increased delamination with all tools, with the dagger drill, increased cutting speed led to a severe increase. Delamination, tearing, and uncut fiber formation were observed when images of the exit areas of the drilled holes were examined.

Multicompartment analysis of the response of lupin hypocotyl segments to the addition and removal of indolyl-3-acetic acid

1972 ◽  
Vol 50 (10) ◽  
pp. 2015-2026 ◽  
Author(s):  
David Penny
Keyword(s):  
Experimental Study ◽  
Growth Rate ◽  
Computer Simulation ◽  
Experimental Results ◽  
The Other ◽  
Allosteric Activation ◽  
Transport Delay ◽  
Different Parts ◽  
Two Alternatives ◽  
Hypocotyl Segments

The typical growth rate curve of the response of lupin hypocotyl to auxin is discussed and explanations suggested for the different parts of the curve. Two alternatives are shown to be able to account for the latent period after auxin addition. One is a linear series of compartments with the transport between compartments similar to allosteric activation in enzyme kinetics and the other alternative is an unmixed compartment (transport delay). Computer simulation is used to test different models to determine whether any model quantitatively predicts the observed results. An example (and variations) of a model is given that predicts much of the experimental results. The model is tested under different conditions such as the addition of different concentrations of auxin, and different times of cycloheximide pretreatment, and on removal from different auxin concentrations. The results of the computer simulations are then compared with experimental results and the model improved to overcome discrepancies. The usefulness of computer simulation in an experimental study is discussed.

scholarly journals Optimization and Effects of Machining Parameters on Delamination in Drilling of Pure and Al2O3 / SiO2 Added GFRP Composites

2021 ◽  
Author(s):  
Ali Ünüvar ◽  
Murat Koyunbakan ◽  
Mehmet Bağcı
Keyword(s):  
Response Surface Methodology ◽  
Glass Fiber ◽  
Response Surface ◽  
Epoxy Composite ◽  
Cutting Speed ◽  
Machining Parameters ◽  
Erosion Wear ◽  
Gfrp Composites ◽  
Pure Epoxy ◽  
Drilling Parameters

Abstract The present study concentrates on optimization and the effect of machining parameters on delamination that occurs during drilling operation of pure glass fiber reinforced polymer (GFRP) composites and added GFRP composites which were developed for resistance to erosion wear. Contribution of drilling parameters to delamination was investigated by using Taguchi method and Analysis of Variance (ANOVA). Relationship between machining parameters and delamination was modelled by using response surface methodology. Correlations were established between the machining parameters by quadratic regression using response surface methodology (RSM). Delamination factors in the hole entrance and exit were obtained in drilling of pure glass-fiber epoxy, SiO2 and Al2O3 added GFRP materials using the experimental plan. Delamination factors at the hole exits were found bigger than delamination factors at the hole entrances. The smallest delamination values were obtained in GFRP/Epoxy composite compared to Al2O3 / SiO2 added GFRP composites at the hole exit. In the investigation of machinability of composites, considering the material as a variable, it has been determined that the material has a greater effect on delamination than the cutting parameters. A new machinability index defined and the material having the best machinability of the three materials was Al2O3 added GFRP composite at the entrance. Good machinability was obtained in drilling of pure GFRP/epoxy composite at the hole exit. It has been found that the effect of feed rate on delamination is greater than the cutting speed and the cutting speed has a low effect. Optimization of the multi-objective function created for maximizing the material removal rate, minimizing the delamination was performed, and the optimum drilling parameters were obtained. As a result of the experimental study, it was found that the amount of delamination increased although the low mechanical properties added GFRP composites with the high resistance to erosion wear in accordance with pure epoxy GFRP composites due to the lack of a strong bond between the epoxy and the fibers in AL2O3 and SiO2. It was observed that the delamination amounts of pure epoxy GFRP, Al2O3 added GFRP, and SiO2 added GFRP composites increased respectively, while the compressive and tensile strengths of these three materials decreased.

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