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Abstract

Natural fiber-based composite materials have found wide applications in Automotive, Aerospace, and Marine Industries. The current study presents the composite preparation, mechanical characterization, and machining behavior of hybrid composite. The fabricated hybrid composite consists of natural fibers (hemp and flax), resin (epoxy and hardener), and S-2304 wire mesh of different orientations (45° and 90°). The mechanical characterization was performed through tensile, flexural, impact, and hardness with ASTM samples. The FRW45 hybrid composite had shown an excellent tensile strength of 43 MPa and 31.57% higher than that of FRW90. Moreover, the FRW45 (82 MPa) flexural strength has shown better results than the HRW45 (76 MPa) composite. The machining performance was studied by drilling experiments, designed by the central composite design (CCD) to study the significant input parameters such as type of composite, speed, and feed rate. The obtained results revealed that torque reduces with the enhancement in feed rate for all types of composites. It was also noticed that at 500 rpm spindle speed, the delamination factor was comparatively 35.03% lower in HRW45 and 58% in HRW90 compared to HR composite. The fiber fracture voids and delamination failures were observed through fractography analysis.

Keywords

Composites wire mesh surface response analysis delamination design of experiments twist drill

Introduction

The composites material's excellent properties make them suitable for lightweight vehicle construction, recyclability, reduction of CO2 emissions, and increasing fuel saving in the automotive industry. Researches are interested in substituting or reducing synthetic fibers instead of traditional glass and carbon fibers. The carbon fiber properties were better than that of natural fiber but still evident that the natural fiber is more widely preferred than the former due to low density, recyclability, environmental concerns, cost, and availability [1]. The significant ingredient such as cellulose, hemicellulose, and lignin contents decides the cellulosic fibers' physical property [2]. The natural fiber composite's energy absorption characteristics were enriched by reinforcing another material to reduce the effect of the variability of fibers [3]. In recent days for many applications, woven fiber bundles like jute, hemp, flax, and kenaf were paying attention to the research community due to their strength and availability and world production per year. However, the hemp and flax fibers had adequate strength, stiffness, and low density to replace the synthetic fibers as reinforcement in the matrix [4]. The mechanical properties of the flax fiber were based on the weaving direction of the fibers, and the diameter of the flax fiber also influences the impact on the composite's tensile behavior. The humidity was affected by flax fiber's tensile properties due to its highly hydrophilic nature [5].

The research peoples have identified the different techniques like fiber combination, particle addition, structural reinforcement, and stacking sequence of fiber, enhancing natural fiber composite properties. The hybrid composite was one of the standard techniques to satisfy the industrial requirements among the various techniques. Two or more polymeric matrix combinations result in better stiffness and strength than an individual reinforced polymeric composite. The vibration and mechanical performance were enriched on the woven fiber composites due to the differences in fiber laminates' stacking sequence [6]. The hybrid composite can provide more impact strength, fatigue resistance, and fracture toughness properties than the mono fiber-reinforced composite [7, 8]. The hybrid composite provides the added advantages on the dynamic mechanical properties enhancement [9, 10]. Hybrid sisal/glass fibers with polyester resin improved the viscoelastic properties such as storage and loss modulus [11]. A limited number of works were reported to reinforce the composites with stainless steel wire mesh on the natural fiber [12, 13]. In the hybrid composite, the chemical treatment and the bonding between the glass fiber and stainless steel wire mesh exhibits better mechanical properties [14]. The pre-treatment enhances the interfacial fracture toughness in the stainless steel epoxy bi-metal composite [15].

The machining performance of the natural fiber composites was useful for joining the two fiber plates or components using rivets, bolts, screws. [16]. The drilling operation creates damages in FRP (Fibre-reinforced plastics) laminates, and various drilling parameters influenced these damages. The drilling quality was predominantly affected by the cutting force, tool geometry, speed, and feed. The drilling of natural fiber composite was performed on the CNC drilling machine by selecting the appropriate speed and feed [17 –19]. The drilled performances on the composite plates were analyzed based on the dimensional accuracy (roundness), surface finish, circularity error, and delamination factor [20 –22]. Among the drilling parameters, the delamination factor (damage around the hole) was critical due to the natural fiber composites' low density. Due to the anisotropy and brittleness of the composite materials, delamination occurs on the fabricated laminate. The machined composite component's structural integrity and long-term reliability were primarily affected by the delamination factor [23]. The delamination damage occurs at the drilled structure's exit and entrance, such as push-out and peel-up. The push-out delamination is more effective than the peel-up delamination [24 –26]. The thrust force and torque play a significant role in determining the delamination factor. The delamination factor can be reduced by using the predrilled pilot hole, special drill bits, and support plates [27].

Given all the optimistic thought, the authors are enthusiastic about developing the hemp/flax hybrid composites for automobile applications. Subsequently, the effects of S-2304 wire mesh angle on woven hemp/flax/epoxy hybrid composites are obtained by mechanical characterization and machining (drilling) performances. The drilling characteristics of HRW45/90 and FRW45/90 composites were studied to understand the effect of cutting parameters such as spindle speed and feed rate. The influence of wire mesh angle on drilling performance with the output variables was studied using thrust force, delamination, and hole quality.

Material and methodology

The epoxy hybrid composite was fabricated with reinforcement of Hemp & Flax and S-2304 wire mesh. The composite plates were prepared using a steel roller, releasing agent, mixing container, stirrer motor, brush, scissor, OHP sheet, mixing bowl, personal protective equipment (PPEs). The woven natural fiber hemp (Bi-directional) and flax (Bi-directional) were procured from Green products Pvt Ltd. The epoxy (LY-556) and hardener (HY-951) were used as a matrix between the fiber layers, and the S-2304 wire mesh was embedded in between the fiber layer (Ram traders Pvt Ltd). The physical and mechanical properties of the hemp, flax, and wire mesh were presented in Table 1.

Table 1.

Properties of Hemp/Flax and wire mesh.

Fiber	Density (g/cm³)	Young's modulus (gpa)	Strength (MPa)	Specific modulus	Specific strength	Ref
Flax	1.4–1.5	50–70	350–1040	18	250–650	[28]
Hemp	1.48	30–60	300–800	25	630	[28]
Wire mesh	Contents (%)	Density (g/cm³)	Young’s Modulus (GPa)	Poison’s ratio & Yield strength (MPa)	Tensile strength (MPa)
Stainless steel wire mesh (S-2304)	Iron (72.679%) Chromium (23%) Nickel (4%) Other (0.321%)	7.8	200	0.333 & ≥ 400	≥600

The weight proportion of the reinforcement and binder plays a vital role in composite fabrication. The hybrid composite plates of 30 $\times$ 30 cm² were fabricated using epoxy resin and hardener. Subsequently, the reinforcement and resins were mixed with the ratio of 1:5. The preparation and characterization of the hybrid composite plate were shown in Figure 1.

Figure 1.

Fabrication and characterization of hybrid composite.

Composite fabrication

A glass mold size of 30 $\times$ 30 $\times$ 0.8 cm with a height of 0.3 cm was used to manufacture hybrid composite. A releasing wax was applied on the OHP sheet (40 $\times$ 40 cm²) surface. To achieve the required composite plate thickness, fiber weight, i.e., flax and hemp, was measured using three decimal accuracy weighing machine. The epoxy resin and hardener mixed with a weight ratio of 10:1 into the mixing pot and stirred up to 2-3 minutes. The woven flax fibre of 30 × 30 cm² was primarily placed on the OHP sheet, and the resin was applied over the surface. Similarly, the resin was applied to the woven hemp fiber on both sides and placed on the OHP sheet. The hybrid composites were prepared with a layer of stainless steel wire mesh placed in between two fiber layers, which were shown in the Figure 2. Two different orientations (45^° and 90^°) of wire mesh were embedded to prepare hybrid hemp and flax fiber composites. The same procedure was followed for the preparation of composite laminate until to get the required thickness. The samples were placed on a flat table. The washers (3 mm) were placed in between the composite sample and glass plate to maintain the composite laminate thickness [29]. The prepared composites were cured at 24 hrs in atmospheric conditions. The weight proportions of the matrix and fibers were depicted in Table 2.

Figure 2.

Combination of hybrid composite preparation.

Table 2.

Different weight proportion of matrix and reinforcements.

Abbreviation	Composite plate(No.of.woven fiber + wire mesh + resin)	Weight in (g)
Abbreviation	Composite plate(No.of.woven fiber + wire mesh + resin)	Fibre (g)	Wire mesh (g)	Epoxy (g)	Hardener (g)	Resin (g)
HR	3 layer Hemp + resin	76	–	342	38	380
HRW45	2 layer Hemp+ wire mesh (45^o orientation)+ resin	50.66	44	338.4	37.6	376
HRW90	2 layer Hemp + wire mesh (90^o orientation)+ resin	50.66	40	326.28	36.26	362.6
FR	3 layer Flax + resin	84	–	378	42	420
FRW45	2 layer Flax + wire mesh (45^o orientation)+ resin	56	44	360	40	400
FRW90	2 layer Flax + wire mesh (90^o orientation)+ resin	56	40	345.6	38.4	384

Experimental details

Mechanical characterization

The mechanical characterization was comprised of tensile, flexural, impact, and hardness. The hybrid composite ASTM test samples were prepared by abrasive water jet machining to avoid crack propagation and delamination. The fractography of the cracked surfaces was analyzed through a scanning electron microscope to recognize microstructural behaviors.

Tensile test

The tensile test was performed to understand the behavior using tensile strength and elastic modulus of the hybrid composite. The stress-strain correlation was used to analyze the tensile behavior graphically. The tensile specimens were prepared using ASTM-D3039M-17 with the specimen dimension of 250 $\times$ 25 $\times$ 3 mm³ [30]. The experimental trials were carried out by using the Instron UTM 5900 universal testing machine (Figure 3(a)). The tensile load was applied on both sides of the specimen in UTM with the crosshead speed of 1 mm/min until the specimen fracture and the average tensile readings were reported.

Figure 3.

Test setup for (a) Tensile test and (b) Flexural test.

Flexural test

The flexural test samples were prepared using the ASTM D790-17 with a dimension of 120 $\times$ 25 $\times$ 3 mm³ [31]. The flexural specimen was subjected to a three-point bend test, and it was conducted in the universal testing machine (UTM) (Figure 3(b)) [32]. The span length between two supports was 90 mm, with a crosshead speed of 1 mm/min was preferred. The flexural sample was initially bent and fractured due to the compressive load applied in the specimen's middle. The deflection and fracture load of the composite were recorded.

Impact test

The Charpy impact specimens were prepared at three different locations on the fabricated hybrid composite plate with the dimensions of 125 $\times$ 12.7 $\times$ 10 mm³ (ASTM D6110-10) [33]. The specimen was damaged due to the sudden pendulum impact load developed at an angle of 135 °C. The average impact energy absorbed by the specimen was recorded.

Hardness test

The hardness of the composite samples was estimated using digital Vicker's hardness testing machine (HVD-1000 AP). The machine has a measuring capacity of a minimum of 0.01 μm and hardness in the range of 1HV - 4000HV. The test specimens were prepared in as per ASTM D2583-13a with a dimension of 12.7 $\times$ 12.7 $\times$ 3 mm³ (Figure 4(a) and (b)) [34]. A diamond pyramid indenter was used, and the depth of penetration was estimated by measuring the indentation dimension.

Figure 4.

Hardness samples (a) ASTM D-2583 (b) Hardness specimen.

Machining characterization

Experimental design

The physical assembly of the automobile's components necessitates fastening. This structure reliability of prepared composite crucial element, and it was desired to analyse machining compatibility by drilling study. An experimental investigation was performed with the statistical experiment design, and the results were evaluated. The experiments were designed and performed using the central composite design (CCD). The CCD was explicitly used to design and conduct a minimum number of experiments with a quadratic response surface. The CCD range was discovered through the full factorial pilot study, and the specific significant responses were observed. The drilling experiments were conducted on the VF30 CNC VS milling machine with a sample size of 10 $\times$ 15 cm. The photographic setup of the drilling study was shown in Figure 5, and the specification of the VF30 CNC VS vertical milling center (VMC) was presented in Table 3. The thrust force and torque were measured using a 9257B Kistler dynamometer attached to the VMC bed [35]. The specification of the dynamometer was depicted in Table 4.

Figure 5.

Experimental drilling setup on the CNC-VMC Machine.

Table 3.

Specification of the CNC VMC.

Model	Surya VF30 CNC VS	Axis drive (feed)	1-5000 mm/min
Table size	315 $\times$ 1060 mm	Machine size	2440 $\times$ 2080 $\times$ 2480 mm
Max.load on table	300 Kg	Weight	2500 kg
Traverse (x,y,z)	800 $\times$ 350 $\times$ 380 mm	CNC system	Fanuc Oi mate
Spindle speed	0-6000 RPM	Power supply	phase 50 Hz

Table 4.

Specification of dynamometer.

Make and model	9257 B Kistler dynamometer
Clamping area	100 $\times$ 170 mm²
Weight	7.3 kg
Operating temperature	0–70▪
Range	−5 to 5 kN

The six different composite design (HR, HRW45, HRW90, FR, FRW45, and FRW90) were considered for the experiment and experimental sample was shown in Figure 6. For the drilling study, the input parameters, such as spindle speed (N) and feed rate (f), were identified through the trial experiment. The input parameters with the three-factor experimental design were shown in Tables 5 and 6. The output responses were analyzed through the thrust force (F), torque (T), and delamination factor (d).

Figure 6.

Composite specimen for drilling.

Table 5.

Drilling parameters and levels for hemp and their associated types.

Factors	Levels
Factors	–1	0	1
Composite type	HR	HRW45	HRW90
Spindle speed (N) in rpm	500	1250	2000
Feed rate(f) in mm/min	50	1025	2000

Table 6.

Drilling parameters and levels for flax and their associated types.

Factors	Levels
Factors	–1	0	1
Composite type	FR	FRW45	FRW90
Spindle speed (N) in rpm	500	1250	2000
Feed rate(f) in mm/min	50	1025	2000

A Dino-Lite (Figure 7) digital microscope was used to analysis of the drilled holes. In Figure 7, the red circle indicates the maximum diameter (D_max) of the delamination zone, and the green circle indicates the drilled hole diameter (D_min). The delamination factor (d) was estimated as the ratio between the maximum diameter (D_max) of the delamination zone to the original hole diameter (D_min) by equation (1) [35].

Delamination factor (d) = \frac{D_{\max}}{D_{\min}}

(1)

Figure 7.

Digital microscopic analysis.

Results and discussion

Mechanical characterization

Tensile test

The tensile stress of the neat hemp fiber withstands up to 37 MPa with an identical strain of 0.017, and the stress was linearly increased concerning the strain value (Figure 8). In the experimental investigation, the specimens were held vertically between the bottom and top heads of the UTM 5900. A tensile load was applied vertically on the composite with the crosshead speed of 1 mm/min until fracture. From the obtained results, the FRW45 composite holds better tensile properties (30.91%) than the FRW90 composite due to the adhesive bonding between the flax fibers (Figure 9).

Figure 8.

Stress vs strain of neat hemp composite (HR).

Figure 9.

Tensile behavior of different hybrid composites.

Similarly, it was found that the physical properties of the flax fiber influencing the tensile strength of the FRW45 composite, and it was 20.03% greater than the HRW45 composite. The length of the crude fiber and ligneous residues as part of the yarn structure significantly influences the tensile strength of neat flax composite (FR-27 MPa) and neat hemp composite (HR-22 MPa) (Figure 9). The appearance of the fiber fracture, fiber pull-out, wire mesh fracture, and voids were observed through the fractography image captured through the failure tensile test specimen (Figure 10(a) and (b)). The inadequate bonding between the fiber and the resin caused the fiber pull-out, and the bonding between the resin and wire mesh was visually analyzed (Figure 10(b)).

Figure 10.

Fractography of the tensile test specimen (a) Fiber pull-out (b) Fiber and wire mesh fracture.

Flexural test

The flexural properties were analyzed with the help of the deflection curve under different loads. The FRW45 was endured the flexural load up to 120 N with the corresponding deflection of 8 mm (Figure 11). The FRW45 composite improved the flexural strength up to 7.59% compared to the FRW90 composite (Figure 12). The 45° oriented wire mesh provided better performance against the bending stress than the 90° oriented wire due to the wire mesh angle's inclination, which withstands more bending stress. However, the physical properties like the length of the crude fiber and cross-section of crude fiber on the flax fiber also play a vital role in enhancing the flexural strength of FRW45 (82 MPa) than the HRW45 (76 MPa). The Figure 12 also depicts that the neat hemp composite (HR) was shown the lowest flexural strength (58 MPa) than the neat flax composite (FR-65 MPa). It occurred due to flax fibre imparts more strength and stiffness because of its constituents (cellulose, hemicellulose, lignin, and pectin) and fibers' containment within the tissue [36]. However, the natural fiber composite's flexural strength was predominantly dependent on the fiber bundle's fiber diameter, length, and thickness. The fiber fracture and tear appearances were observed through the fractography analysis obtained from the flexural test specimen (Figure 13(a) and (b)). There was no evidence which claims the delamination between the fiber/resin/wire mesh/resin. (Figure 13(b)).

Figure 11.

Load vs deflection of FRW45 composite.

Figure 12.

Flexural behavior of different hybrid composites.

Figure 13.

Fractography of flexural test specimen (a) Fiber fracture and tear (b) Wire mesh fracture.

Impact test

The impact analysis observed from the test results that the FRW45 composite showed a 10.4% better toughness value than the FRW90 composite (Figure 14). However, the FRW45 hybrid composite was exposed to the improved toughness of 60.89% more than the three-layer neat flax composite (FR) [37]. The significant adhesive bonding interpreted the wire mesh between the flax fiber and the wire mesh. It also creates a delay in crack initiation when the load was applied, which increased the load-bearing capacity or maximum load at break value. In contrast, the results associated with the HRW45 composite have shown lower impact strength (1.4 J) than the FRW45 composite (1.7 J) due to the short length of the crude fiber, and ligneous residues as part of the yarn structure significantly influence the impact strength. The Figure 14 also reveals that the neat flax composite (FR) has shown better impact strength (1.15 J) than the neat hemp composite (HR-0.85J).

Figure 14.

Impact strength of various composites.

Hardness test

While comparing the Vickers hardness value of the 45° oriented hemp and flax fiber composite, the FRW45 composite was shown 2.5% more hardness value than the HRW45. The FRW90 composite was shown a comparatively better hardness value (24.43 VHN) than the HRW90 (22.63 VHN) (Figure 15). The Vickers hardness values were improved due to the type of fiber and reinforcement of wire mesh, which increase the composites' stiffness. The neat flax composite (FR) was shown a slightly better hardness value (21VHN) than the neat hemp composite (HR-20VHN). However, the natural fibre composite material's hardness behavior primarily depends on its properties (physical, mechanical, and chemical), level of adhesion, and fiber loading. The results further revealed that the wire mesh angle influenced the hardness enhancement. The amount of resin and fibers was predominantly responsible for enhancing the hardness value for the prepared composite.

Figure 15.

Hardness value of various hybrid composites.

Machining characterization

Composite drilling

Delamination factor, thrust force, and torque were analyzed at different feed rates and spindle speeds for the twist drilling tool. The VF30 CNC VS experimental drilling trails and the corresponding response were reported in Tables 7 and 8. Three input levels were considered for both hemp and flax fiber composites. The output responses were measured based on the thrust force, torque, and delamination factor.

Table 7.

Experimental design and corresponding responses for hemp composites.

Exp	Input parameters			Responses
Exp	Composite type	Spindle speed (N) (rpm)	Feed rate (f) (mm/min)	Thrust force (F) N	Torque (T) Nm	Delamination factor (d)
1	HR	500	50	64.93	0.17	1.00
2	HR	1250	1025	625.00	0.73	1.25
3	HR	2000	2000	724.50	0.55	1.29
4	HRW45	500	1025	533.90	0.52	1.57
5	HRW45	1250	1025	617.10	0.74	1.24
6	HRW45	1250	1025	627.70	0.85	1.25
7	HRW45	1250	1025	598.30	0.85	1.26
8	HRW45	1250	50	39.81	0.13	1.02
9	HRW45	1250	2000	1175.00	1.01	1.49
10	HRW45	2000	1025	361.70	0.55	1.23
11	HRW90	500	2000	800.00	1.61	2.50
12	HRW90	1250	1025	612.00	0.75	1.28
13	HRW90	2000	50	45.96	0.13	1.05

Table 8.

Experimental design and corresponding responses for flax composites.

Exp	Input parameters			Responses
Exp	Composite type	Spindle speed (N) rpm	Feed (f) mm/min	Thrust force (F) N	Torque(T) Nm	Delamination factor (d)
1	FR	500	50	64.69	0.29	1.02
2	FR	1250	1025	415.30	0.52	1.50
3	FR	2000	2000	462.20	0.36	1.43
4	FRW45	500	1025	700.00	1.61	1.16
5	FRW45	1250	1025	330.60	0.83	1.21
6	FRW45	1250	2000	550.00	1.32	1.19
7	FRW45	1250	1025	341.60	0.83	1.21
8	FRW45	1250	50	64.32	0.15	1.12
9	FRW45	1250	1025	312.30	0.83	1.21
10	FRW45	2000	1025	362.60	0.43	1.14
11	FRW90	500	2000	1300.00	1.40	1.52
12	FRW90	1250	1025	370.60	0.46	1.28
13	FRW90	2000	50	61.72	0.29	1.13

The mathematical models were developed from the obtained experimental results by using regression equations [38]. The model quantitatively relates the input variable responses of the empirical equation (equation (2)).

Empirical model and data analysis

The regression equation's general format was obtained in the empirical equation (equation (2)). In the general empirical equation, the Y represents the response variable, $X i X j$ was the input variables, and $β 0, β i, β i i, β i j$ was the regression coefficients.

Y = β 0 + \sum_{i = 1}^{k} β iXi + \sum_{i = 1}^{k} β iiXi 2 + \sum \sum_{i < j} β ijXi X j

(2)

The theoretical model for the thrust force (N), torque (Nm), and delamination factor (d) for the hemp composites (HR, HRW45, and HRW90) were presented (equations (3) to (5)). Likewise, the theoretical equations for flax composites (FR, FRW45and FRW90) were presented from equations (6) to (8).

Compsite type	Thrust force (N)	Torque (Nm)	Delamination factor (d)
Hemp fiber Composites	11.014–6.694 × C + 0.002 × N + 0.026 × f + 0.005 × C × N–0.0014 × C × f + 0.407 × C²–6.0437E-06 × N²–4.38E-06 × f²	2.37 + 0.188 × C-0.0017 × f–0.0002 × C × f + 6.79E-07 × f²	0.929 + 0.072 × C–1.64E-05 × N + 0.0005 × f–0.0002 × C + 0.0001 × C × f–4.12E−07 × N × f + 0.0366 × C² + 3.008E−07 × N²
	(3)	(4)	(5)
Flax fiber Composites	−68.59 + 254.49 × C–0.25× N + 0.75 × f–0.22 × C × N–0.0003 × N × f + 0.00030 × N²-5.55E-05 × f²	0.087 + 1.194 × C–0.002× N + 0.0019 × f + 0.0003× C × N-0.00033 × C × f–3.95E-07 × N × f–0.341 × C ² +3.36E–07 × N²–9.82E–08 × f²	1.035-0.53 × C + 0.00090 × N + 0.00046 × f −0.00021 × C × N −1.76E-05 × C × f −2.169E-07× N × f + 0.179 × C ² −1.04E–07 × N² −6.13E-08 × f²
	(6)	(7)	(8)

The analysis of variance had been preferred to analyze the competence of the newly developed model. It was observed from the theoretical model, the model p-values were less than 0.0500 for all the tables (Tables 9 to 14), and the obtained result supports that the developed empirical model is significant. The theoretical model was significantly compared and verified with the obtained lesser p-value (0.0001) (95% confidence) than the thrust force and torque model (Tables 9 to 14).

Table 9.

ANOVA for regression equation (3).

Source	Sum of squares	df	Meansquare	F value	p-valueProb > F
Model	929.83	8	116.23	1035.48	<0.0001	significant
Composite type (C)	0.00	1	0.00	0.04	0.8441
Spindle speed (N), rpm	8.36	1	8.36	74.44	0.0010
Feed (f), mm/min	391.13	1	391.13	3484.54	<0.0001
CN	20.21	1	20.21	180.07	0.0002
Cf	2.55	1	2.55	22.70	0.0089
C²	0.42	1	0.42	3.77	0.1240
N²	29.49	1	29.49	262.73	<0.0001
f²	44.33	1	44.33	394.93	<0.0001
Residual	0.45	4	0.11
Lack of Fit	0.27	2	0.13	1.48	0.4032	not significant
Pure Error	0.18	2	0.09
Cor Total	930.28	12

Table 10.

ANOVA for regression equation (4)

Source	Sum of squares	df	Mean square	F value	p-value Prob > F
Model	5.406524	4	1.351630887	82.07103	<0.0001	significant
Composite type (C)	0.011148	1	0.011147627	0.676884	0.4345
Feed (f), mm/min	3.852373	1	3.852373153	233.9161	<0.0001
Cf	0.194404	1	0.194403814	11.8042	0.0089
f²	1.348599	1	1.348598952	81.88693	<0.0001
Residual	0.131752	8	0.016469038
Lack of Fit	0.128053	6	0.021342117	11.5375	0.0819	not significant
Pure Error	0.0037	2	0.001849804
Cor Total	5.538276	12

Table 11.

ANOVA for regression equation (5).

Source	Sum ofsquares	df	Meansquare	F value	p-valueProb > F
Model	1.762924	8	0.220365527	557.5669	<0.0001	significant
Composite type (C)	0.000381	1	0.000380604	0.963001	0.3820
Spindle speed (N), rpm	0.055678	1	0.055678179	140.8764	0.0003
Feed (f), mm/min	0.108723	1	0.108723441	275.0911	<0.0001
CN	0.053695	1	0.05369461	135.8576	0.0003
Cf	0.020045	1	0.020044855	50.71731	0.0021
Nf	0.121328	1	0.121327853	306.9826	<0.0001
C²	0.003714	1	0.003714407	9.398158	0.0375
N²	0.07907	1	0.079069566	200.0611	0.0001
Residual	0.001581	4	0.000395227
Lack of Fit	0.00143	2	0.000714882	9.459598	0.0956	not significant
Pure Error	0.000151	2	7.55721E-05
Cor Total	1.764505	12

Table 12.

ANOVA for regression equation (6).

Source	Sum of squares	df	Mean square	F value	p-value Prob > F
Model	1275037.17	7	182148.17	115.68	<0.0001	significant
Composite type (C)	999.05	1	999.05	0.63	0.4618
Spindle speed (N), rpm	231347.42	1	231347.42	146.92	<0.0001
Feed (f), mm/min	117942.53	1	117942.53	74.90	0.0003
CN	36788.94	1	36788.94	23.36	0.0047
Nf	71183.42	1	71183.42	45.21	0.0011
N²	81060.63	1	81060.63	51.48	0.0008
f²	7706.44	1	7706.44	4.89	0.0779
Residual	7873.00	5	1574.60
Lack of fit	7434.87	3	2478.29	11.31	0.0823	not significant
Pure error	438.13	2	219.06
Cor total	1282910.17	12

Table 13.

ANOVA for regression equation (7).

Source	Sum of squares	df	Mean square	F value	p-value Prob > F	Source
Model	2.673	9	0.30	297208.19	<0.0001	significant
Composite type (C)	0.002	1	0.00	1689.21	<0.0001
Spindle speed (N), rpm	0.698	1	0.70	698553.25	<0.0001
Feed (f), mm/min	0.690	1	0.69	690300.38	<0.0001
CN	0.114	1	0.11	114345.86	<0.0001
Cf	0.146	1	0.15	146004.47	<0.0001
Nf	0.111	1	0.11	111473.50	<0.0001
C²	0.297	1	0.30	296964.50	<0.0001
N²	0.091	1	0.09	91322.72	<0.0001
f²	0.022	1	0.02	22278.68	<0.0001
Residual	0.000	3	0.00
Lack of fit	0.000	1	0.00	9.99	0.0872	not significant
Pure error	0.000	2	0.00
Cor total	2.673	12

Table 14.

ANOVA for regression equation (8).

Source	Sum of squares	df	Mean square	F value	p-value Prob > F	Source
Model	0.28	9	0.03	5491.86	<0.0001	significant
Composite type (C)	0.02	1	0.02	4077.70	<0.0001
Spindle speed (N), rpm	0.00	1	0.00	33.40	0.0103
Feed (f), mm/min	0.00	1	0.00	447.90	0.0002
CN	0.04	1	0.04	6323.16	<0.0001
Cf	0.00	1	0.00	70.41	0.0036
Nf	0.03	1	0.03	5976.18	<0.0001
C²	0.08	1	0.08	14688.37	<0.0001
N²	0.01	1	0.01	1575.66	<0.0001
f²	0.01	1	0.01	1545.88	<0.0001
Residual	0.00	3	0.00
Lack of fit	0.00	1	0.00	1.48	0.3483	Not significant
Pure error	0.00	2	0.00
Cor total	0.28	12

Surface response analysis

The interaction effect between the input and output responses were analyzed through response surface methodology (RSM) by the surface analysis (Figures 16 and 17). The RSM analysis observed that all the input factors such as feed rate, spindle speed, and composite type (HR, HRW45, HRW90, FR, FRW45, FRW90) contribute significantly to the predicted output responses like thrust force, torque, and delamination factor. Figure 16(a) to (f) was shown that the surface response for input and output responses of HR, HRW45, HRW90 composites. From Figure 16(a), the HR composite at a lower spindle speed of 500 rpm, the thrust force was higher, and it was decreased with the increase in spindle speed. Whereas in HRW45 and HRW90 composites, at a lower spindle speed of 500 rpm, a lower thrust force value was observed, and it increases with an increase in spindle speed. At higher spindle speed, maximum thrust force was recorded in HRW90 composite than other composites, and the wire mesh angle influences the outputs like thrust force, torque, and delamination factor specifically the HRW90 increased the thrust force to maximum compare to other composite types. From Figure 16(b), an increase in feed rate increased the thrust force for HR, HRW45, and HRW90 type composites. Figure 16(c) for the HR, HRW45, and HRW90 type composites, higher torque was observed at low feed rates and decreased with increased feed rates. Maximum torque was noted in HRW90 composite at the lowest feed rate of 50 mm/min. The higher flexural and toughness properties increased the thrust force, and torque in the wire mesh reinforced composite. It was also observed that the thrust force was affected by mesh angle, spindle speed, and feed rate.

Figure 16.

(a-f) Surface response for HR, HRW45, HRW90 composites.

Figure 17.

Surface response for FR, FRW45, and FRW90 composites.

The delamination factor was less in HR composite at a minimum spindle speed of 500 rpm (Figure 16(d). But the wire mesh reinforced composites (HRW45 & HRW90) were shown a higher delamination factor at lower spindle speed. In general, the increase in spindle speed decreased the delamination factor. Considerably an increase in feed rate and spindle speed increased the composite's delamination (Figure 16(e) and (f)). The delamination was observed maximum in the wire mesh reinforced composites at higher spindle speed with a lower feed rate combination.

The Figure 17(a) to (f) was shown the surface response of FR, FRW45, and FRW90 composites. The Figure 17(a) was shown the decrease in thrust force with an increase in spindle speed. The maximum thrust force was obtained with 500 rpm spindle speed for wire mesh reinforced composites due to wire mesh resistance against the composite's plates' penetration. The thrust force increased with the increased feed rate for FR type composite (Figure 17(b)).

It was observed from the obtained results, the torque was maximum at a lower spindle speed (500 rpm), and it was decreased considerably with an increase in spindle speed irrespective of the composite type. The lowest torque was recorded for FR type composite at 2000 rpm, and it was maximum for the flax wire mesh composite. From Figure 17(c) and (d), increasing feed increases the torque irrespective of the composite type. At maximum feed rate, a value of 79.28%, higher torque was found in FRW90 composite.

It was observed from the Figure 17(e) and Figure 17(f), the delamination factor increases 32.89% with an increase in feed and minimum spindle speed for flax wire mesh composites (FRW45 & FRW90). The delamination factor was maximum for FR type composite at a spindle speed of 2000 rpm and feed rate of 2000 mm/min. The thrust force, torque, and delamination factor were higher for HR and FRW90 than HRW45, HRW90, FR, and FRW45, irrespective of various feed and spindle speeds. It was understood that the tensile strength properties of the former composites were better than later.

Conclusion

The present work reported a comprehensive study on the behavior of hybrid flax and hemp composite reinforced with S-2304 wire mesh. Based on the obtained results, the following conclusions were prepared.

The wire mesh–epoxy significantly enriches the mechanical performance. FRW45 composite increases the tensile strength up to 20.03% over the hemp fiber composite.

The wire mesh angle marginally influences the flexural and toughness properties of the hybrid composites. However, the toughness of the FRW45 composite increases by 60.89% compared to the three-layer neat fiber composite (FR).

The reinforced wire mesh angle (both 45° and 90°) revealed an increase in the initial crack load.

The delamination was reduced up to 25.65% in FRW90 composite and 7.43% in FRW45 composite with the higher spindle speed and lower feed rate.

The feed rate significantly influences the thrust force, torque, and delamination factor in the hemp fiber composite with the wire mesh's different orientations.

In general, the flax fiber composite performs better performance with the wire mesh in all aspects. Finally concluded that for better geometrical accuracy, the delamination factor was kept at the minimum value, which was achieved by maintaining low feed and speed irrespective of the composites' type and orientation.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Prabu Krishnasamy

G Rajamurugan

References

Bhoopathi

Ramesh

Naveen Kumar

et al. Studies on mechanical strengths of hemp-glass fiber reinforced epoxy composites. IOP Conf Ser: Mater Sci Eng 2018; 402: 012083.

Ramesh

Palanikumar

and Hemachandra Reddy

Evaluation of mechanical and interfacial properties of sisal/jute/glass hybrid fiber reinforced polymer composites. Trans Indian Inst Met 2016; 69: 1851–1859.

Di Landro

and Janszen

Composites with hemp reinforcement and bio-based epoxy matrix. Comp Part B Eng 2014; 67: 220–226.

Shahzad

Hemp fiber and its composites – a review. J Comp Mater 2012; 46: 973–986.

Davies

and Bruce

DM.

Effect of environmental relative humidity and damage on the tensile properties of flax and nettle fibers. Text Res J 1998; 827: 337–344.

Sathishkumar

Naveen

Navaneethakrishnan

et al. Characterization of sisal/cotton fiber woven mat reinforced polymer hybrid composites. J Ind Text 2017; 47: 429–452.

Sankar

et al. Drilling of composite Laminates- A review. J Basic App Eng Res 2014; 1: 19–24.

Dong

Locquet

Declercq

and Citrin

DS.

Polarization-resolved terahertz imaging of intra- and inter-laminar damages in hybrid fiber-reinforced composite laminate subject to low-velocity impact. Comp Part B Eng 2016; 92: 167–174.

Jacob

Francis

Thomas

et al. Dynamical mechanical analysis of sisal/oil palm hybrid fiber-reinforced natural rubber composites. Polym Compos 2006; 27: 671–680.

10.

Xiaoning Tang and Xiong Yan. A review on the damping properties of fiber reinforced polymer composites. J Ind Text 2018; 49: 693–721. DOI: 10.1177/1528083718795914.

11.

Ornaghi

Jr Bolner

Fiorio

et al. Mechanical and dynamic mechanical analysis of hybrid composites molded by resin transfer molding. J Appl Polym Sci 2010; 118: 887–896.

12.

Krishnasamy

Rajamurugan

and Thirumurugan

Dynamic mechanical characteristics of jute fiber and 304 wire mesh reinforced epoxy composite. J. Ind. Text Epub Ahead of Print 29 October 201. DOI:10.1177/1528083719883057.

13.

Huagui

Jichao

and Wenwen

Mechanical properties and reinforced mechanism of the stainless steel wire mesh-reinforced Al-matrix composite plate fabricated by twinroll casting. Adv Mech Eng 2017; 9: 1–9.

14.

Karunagaran

and Rajadurai

Effect of surface treatment on mechanical properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites. J Mech Sci Technol 2016; 30: 2475–2482.

15.

Kanerva

and Saarela

OlliSaarela X-ray diffraction and fracture based analysis of residual stresses in stainless steel–epoxy interfaces with electropolishing and acid etching substrate treatments.

Int J Adhe & Adhes 2012; 39: 60–67.

16.

Arulmurugan

Selvakumar

Prabu

and Rajamurugan

Effect of barium sulphate on mechanical, DMA and thermal behavior of woven aloe vera/flax hybrid composites. Bull. Mater. Sci 2020; 43: 1–10.

17.

Babu

Sunny

Paul

et al. Assessment of delamination in composite materials: a review. Proc Inst Mech Eng B 2016; 230: 1990–2003.

18.

Babu

Alex

Mohan

et al. Examination and modification of equivalent delamination factor for assessment of high-speed drilling. J Mech Sci Technol 2016; 30: 5159–5165.

19.

Lissek

Tegas

and Kaufeld

Damage quantification for the machining of CFRP: an introduction about characteristic values considering shape and orientation of drilling-induced delamination. Procedia Eng 2016; 149: 2–16.

20.

Sakthivel

Ravichandran

and Alagumurthi

An experimental study on mesh-and-Fiber reinforced cementitious composites. Concr. Res. Lett 2014; 5

21.

Banakar

Preparation, and characterization of the carbon fiber reinforced epoxy resin composites. Iosrjmce 2012; 1: 15–18.

22.

Song

Byun

Song

et al. Experimental and numerical investigation on impact performance of carbon-reinforced aluminium laminates. J. Mater. Sci. Technol 2010; 26: 327–332.

23.

Khashaba

Delamination in drilling GFR-thermoset composites. Comp Struct 2004; 63: 313–327.

24.

Huang

Trask

and Bond

IP.

Characterization and analysis of carbon fibre-reinforced polymer composite laminates with embedded circular vasculature. J R Soc Interface 2010; 7: 1229–1241.

25.

Tamilarasan

Karunamoorthy

and Palanikumar

Mechanical properties evaluation of the carbon fibre reinforced aluminium sandwich composites. Mat Res 2015; 18: 1029–1037.

26.

Ion

Adriana

and Ana

, Aerospace Consulting Bdul Iuliu Maniu 220, Bucharest 061136, Romania idinca@incas.roAluminum/glass fibre and aluminium/carbon fibre hybrid laminates. Incas Bull 2010; 2: 33–39.

27.

Rajamurugan

GAPS

Krishnasamy

Muralidharan

et al. Drilling and mechanical performance of Flax-Sisal hybrid composites embedded with perforated aluminium foil. J Rein Plast and Comp, Epub Ahead of Print 2020; 30 June 2020. DOI:https://doi.org/10.1177/0731684420937070.

28.

Vaisanen

Das

and Tomppo

A review on new bio-based constituents for natural fiber-polymer composites. J. Clean.Prod 2017; 149: 582–596.

29.

Erturk

Vatansever

Yarar

Karabay

et al. Machining behaviour of multiple layer polymer composite bearing with using different drill bits. Compos. Part B 2019; 176: 107318.

30.

ASTM D3039/D3039M-17. Standard test method for tensile properties of polymer matrix composite materials. West Conshohocken, PA: ASTM International, 2017.

31.

ASTM D790-17. Standard test methods for flexural properties of unreinforced and reinforced plastics and electrical insulating materials. West Conshohocken, PA: ASTM International, 2017.

32.

Krishnasamy

Rajamurugan

and Thirumurugan

Performance of fiber metal laminate composites embedded with Al and Cu wire mesh. J Ind Text 2020; Epub ahead of print 22 June 2020. https://doi.org/10.1177/1528083720935570.

33.

ASTM D6110-10. Standard test method for determining the charpy impact resistance of notched specimens of plastics. West Conshohocken, PA: ASTM International, 2010.

34.

ASTM D2583-13a, Standard test method for indentation hardness of rigid plastics by means of a barcol impressor,. ASTM International, West Conshohocken, PA, 2013. www.astm.org.

35.

Kumar Bajpai

Debnath

and Singh

Hole making in natural fiber-reinforced polylactic acid laminates: an experimental investigation. J.Thermo.Comp.Mat 2017; 30: 30–46.

36.

Lee

Khalina

Lee

et al. A Comprehensive Review on Bast Fibre Retting Process for Optimal Performance in Fibre-Reinforced Polymer Composites, 2020. 2020: 1-27.

37.

Prabu Krishnasamy

Rajamurugan

Aravindraj

PE.

and Sudhagar

Vibration and wear characteristics of aloevera/flax/hemp woven fiber epoxy composite reinforced with wire mesh and BaSO4. J.Nat.Fib 2020; DOI: 10.1080/15440478.2020.1835782

38.

Bajpai

and Singh

Drilling behavior of sisal fiber-reinforced polypropylene composite laminates. J.Rein.Plas and Comp 2013; 32: 1569–1576.

Effect of S-2304 wire-mesh angle in hemp/flax composite on mechanical and twist drilling surface response analysis

Abstract

Keywords

Introduction

Material and methodology

Composite fabrication

Experimental details

Mechanical characterization

Tensile test

Flexural test

Impact test

Hardness test

Machining characterization

Experimental design

Results and discussion

Mechanical characterization

Tensile test

Flexural test

Impact test

Hardness test

Machining characterization

Composite drilling

Empirical model and data analysis

Surface response analysis

Conclusion

Footnotes

Declaration of conflicting interests

Funding

ORCID iDs

References