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Abstract

Nowadays, using three dimensional fabric as a reinforcement part in the composite has been increased. Non-crimp three dimensional orthogonal woven fabric is a subgroup of 3D woven fabrics that in this study was used to fabricate composite preforms. The fabrics were produced by glass yarn in two different fiber volume fractions. All fabric preforms were utilized to produce composites with polyester and epoxy resins. To compare the torsional behavior of the composites, a torsion test was applied to all samples and torque-revolution curves from the experimental results were compared together. Results showed that composites that were fabricated by epoxy resin have more torsional strength in comparison with composites in that their matrix is polyester resin. Moreover, preforms with high fiber volume fractions showed high torsional strength in each type of matrix. The torsion strength of high volume fraction for polyester matrix was 47.34 KPa, however for the sample with epoxy matrix the torsion strength was determined 81.26 KPa. Furthermore, a multiscale finite element model was applied to calculate elastic constants and predict the torsional behavior of the composites. The numerical results were compared with experimental results that a good agreement between numerical and experimental results was observed. Therefore, the proposed model can predict the torsional behavior of the composite with different fiber volume fractions.

Keywords

Non-crimp orthogonal woven fabric torsional behavior composite glass yarn multi-scale finite element method

Introduction

In the recent era, composite materials have been used in many industries extensively.^1–3 Lightweight besides high mechanical properties of textile preform lead to having been considered by many researchers to use them as a reinforcement part for composite structures.^2,5 3D textile composite is one of the subgroup of composites that could be fabricated by various methods such as weaving, knitting, and braiding.⁶ Textile architecture and the orientation of fibers play a considerable role in the composite’s mechanical features. Yarn crimp is one of the effective parameters on stiffness and strength of the composite that can reduce these mechanical properties. Moreover, by adding straight yarns within the composite structure, volume fraction, stiffness, and strength of the composite are increased.^7–9 So, it can be concluded that textile structures with more number of straight yarns, have high mechanical properties.

Non-crimp three dimensional orthogonal woven (NC3DOW) fabric is a subgroup of 3D woven textiles in which yarns are aligned straightly in the fabric structure. Non-crimp yarns indicate maximum resistance under external load in different directions. Moreover, designing a composite with a high fiber volume fraction in this fabric is easier than others.^10,11 Some studies have been conducted to investigate the mechanical behavior of NC3DOW fabric. Karahan et al.¹² investigated the internal geometry of NC3DOW composite by image processing. They compared the geometry of this fabric with other 2D and 3D fabrics. They also in another study examined fatigue tensile performance of carbon/epoxy composite with NC3DOW preform.¹³ The impacts of temperature on the fatigue behavior of an NC3DOW composite were assessed by Wilkinson and Ruggles-Wrenn.¹⁴ The results showed that increase in temperature imposed a slight impact on the composites’ on-axis tensile features. The impact properties of this structure are other considerable properties that were studied by Hu et al.¹⁵ Minapoor et al., in another work,¹⁰ investigated the tensile strength of a novel NC3DOW with two different yarn densities. This fabric was produced by a self-designed loom. The yarns are aligned in three different directions and the fiber volume fraction of the preform can be changed by changing the yarn orientation angle.

On the other hand, computational methods have been had a great effect on predicting the thermal and mechanical features of the composite preforms. In this vein, the finite element method is one of the numerical approaches that have been used widely by researchers in this field.^5,16–20 Multi-scale finite element modeling is a subgroup of the finite element method that improves the accuracy of the model to predict the final properties of the composite. In this technique, a unit-cell of the composite includes fibers and matrix at the meso scale is modeled and mechanical properties of the composite such as elastic constants or failure parameters are extracted from the unit-cell. Afterward, the actual load based on the experimental procedure is applied to the macro model to analyze the mechanical behavior of the composite.^17,21–24

According to previous studies, the majority of research has been focused on tensile and flexural properties of the NC3DOW composites and there are limitation papers that have investigated other properties such as the torsional behavior of NC3DOW composites. The torsional behavior of the composite shows the effect of fiber orientation and shear stiffness of the composite. Therefore, in this paper torsional behavior of NC3DOW composites with two different fiber volume fractions and two matrixes was examined. The structure of the NC3DOW fabric was mentioned in Ref. 10. Besides, a multi-scale finite element modeling was utilized to predict the linear behavior of the composites under torsional load.

Materials and experimental procedure

For experimented work, glass yarns were used to produce NC3DOW fabric. The NC3DOW samples were fabricated by a self-designed loom based on the uniaxial noobing process.²⁵ In this fabric, there are three sets of non-crimp yarns that are aligned in x, y, and z directions. The tension of longitudinal yarns is defined in two terms, namely no-stress state and prestress state. No-stress state means the longitudinal yarns (Z-yarns) set on the loom smoothly and without any stretching. In pre-stress state, glass tows are subjected to 120 N force according to their force-elongation curves and then the weaving process is done. The specific structure of the fabric leads to fabricate a fabric with a high volume fraction of fiber. Indeed, the absence of any interlacing (as woven fabrics), interlooping (as knitted fabrics), or intertwining (as braids) of the involved yarns causes more fiber content in these structures. In this loom, two lattice plates are set on top and bottom of the loom. The Z-yarns are passed through these plates. Two sets of tows are kept by two needle sets and during the weaving process are moved forward and backward. So, 3D non-crimp orthogonal fabric is made by this process. Figure 1 shows two views of the loom during the weaving process.

Figure 1

Weaving process of the fabric by the self-designed loom, (a) side view and (b) bottom view.

Mechanical features of the glass yarn according to ASTM D2256 were obtained. Table 1 shows the mechanical and physical characteristics of the glass yarn.

Table 1.

Physical and mechanical properties of the glass yarn.

Density (g/cm³)	Yarn count (Tex)	Young modulus (GPa)	Tensile strength (Mpa)	Failure strain (%)
2.54	1200	72	3448	0.048

Fabrics were produced in two different fiber volume fractions and Table 2 illustrates the structural parameters for each fabric. In order to increase the fiber volume fraction, the let-up and take up’ speed for Z-yarn is reduced that leads to weft yarns align within the fabric structure with a high orientation angle. So, the fiber volume fraction of the fabric is increased. The values of fiber volume fraction for each composite were measured by the burning-off technique according to ASTM D 3171–3199.²⁶ Figure 2 shows the real and schematic structure of the fabrics.

Table 2.

Fabric’s Structural parameters.

Fabric	Orientation angle (degree)	Volume fraction	Code
Low volume fraction	30	0.197 ± 0.02	LVF
High volume fraction	90	0.29 ± 0.03	HVF

Figure 2.

Real and schematic figure of the fabrics, (a) low volume fraction and (b) high volume fraction.

The glass yarns and resins were supplied from CAM ELYAf and Boushehr chemical industry companies, respectively. Epoxy and polyester resin were utilized to produce composite preforms. Table 3 represents the physical and mechanical features of polyester and epoxy resins.

Table 3.

The mechanical and physical features of the epoxy and polyester resins.

Resin	Density (kg/m3)	Young modulus (MPa)	Tensile strength (MPa)
Epoxy	1460	3130	64.3
Polyester	1250	1320	21.4

The vacuum injection process (VIP) was used to manufacture all composites samples. The epoxy and polyester resins were thoroughly mixed with their corresponding hardener with a weight fraction ratio of 100:30. Then, prior to be used in the vacuum bag molding process, the deaeration process was performed by placing the prepared mixture in the vacuum oven under a pressure of 65 bar, at 30^oC temperature for 15 min. The molded samples were kept at room temperature for 24 h to be cured. For improving their mechanical properties, the samples were then post-cured during further three different heating processes in an oven: for 2 h at 45°C temperature, for the next 2 h at 60°C temperature, and the final 8 h at 80°C temperature. Figure 3 shows NC3DOW fabrics and composite samples.

Figure 3.

(a) Vacuum injection process and (b) composite samples.

In order to obtain the torsional strength of the composites, a torsion test was performed on all samples based on ASTM D198 standard. In this test one side of the sample is fixed by a grip and a torque load with speed 0.2 rev/min is applied to the other side of the sample. The length and diameter of the samples were set 81 mm and 8.5 mm, respectively. The test setup is shown in Figure 3. For each composite structure, three specimens were tested and the average of outputs was reported (Figure 4).

Figure 4.

Torsional test. Multi-scale finite element model.

To obtain mechanical constants of the composite, a unit cell of the composite was modeled in ABAQUS finite element software. The diameter of the yarns is 1.1 mm

The yarn was impregnated with resin over the composite production procedure. The impregnated yarn was presumed as a unidirectional composite with fiber volume fraction equivalent to the yarn’s packing density

V_{f} = p_{d}

(1)

where P_d represents the yarn’s packing density. The resin volume fraction in the saturated yarn is

V_{r} = 1 - p_{d}

(2)

According to previous studies,^5,18,27,28 the Chamis²⁹ model is a suitable model to calculate elastic constants of the resin-impregnated yarn. So, the Chamisa²⁹ micromechanical model is utilized for determining the elastic coefficients of unidirectional composites isotropic transversely.

E_{11} = V_{f} E_{11 f} + V_{r} E_{r}

(3)

E_{22} = \frac{E_{r}}{1 - \sqrt{V_{f}} (1 - \frac{E_{r}}{E_{22 f}})}

(4)

G_{12} = \frac{G_{r}}{1 - \sqrt{V_{f}} (1 - \frac{G_{r}}{G_{12 f}})}

(5)

G_{23} = \frac{G_{r}}{1 - \sqrt{V_{f}} (1 - \frac{G_{r}}{G_{23 f}})}

(6)

υ_{12} = V_{f} ν_{12 f} + V_{r} ν_{r}

(7)

ν_{23} = \frac{E_{22}}{2 G_{23}} - 1

(8)

Table 4 shows the elastic constants of yarn impregnated with resin.

Table 4.

The elastic coefficients of the resin-impregnated yarn.

Matrix	E11 (MPa)	E22 (MPa)	E33 (MPa)	ν12	ν13	ν23	G12 (MPa)	G13 (MPa)	G23 (MPa)
Epoxy	32,226	3986	3986	0.29	0.29	0.34	1478	1478	1478
Polyester	32,226	1693	1693	0.29	0.29	0.34	627	627	627

To determine the constants of the composite’s stiffness matrix, periodic boundary conditions were applied to the meso model. The macroscopic strain increment was applied to the unit-cells by decomposing the displacement increment on the boundary into the macroscopic averaged displacement field and a period part repeated from one unit-cell to another one, such as

U_{i} = {\bar{ε}}_{i k} X_{k} + U_{i}^{*}

(9)

where

{\bar{ε}}_{i k} = {\dot{ε}}_{i k} Δ t

is the macroscopic strain increment. As the periodic part of

U_{i}^{*}

is equal on the corresponding nodes of the opposite parallel surface of unit-cell, the total displacement at this node pair is expressed by

{(U_{i})}_{n_{1}^{p}} - {(U_{i})}_{n_{2}^{p}} = {\bar{ε}}_{i k} [{(X_{k})}_{n_{1}^{p}} - {(X_{k})}_{n_{2}^{p}}] = {\bar{ε}}_{i k} Δ X_{k}

(10)

where

Δ X_{k}

is the relative coordinates of the node pair and

n_{1}^{p}

and

n_{2}^{p}

are the first and second node, respectively .¹⁷ Periodic boundary circumstances were utilized to the unit cell that are shown in Figure 5.

Figure 5.

The periodic boundary circumstances, (a) tensile load low volume fraction sample and (b) shear load on high volume fraction sample.

C3D8R element types in ABAQUS/Standard element library were utilized as an 8-node linear, to mesh the model. Figure 6 represents the unit-cell followed by the meshing procedure. Through a Mesh dependency investigation on the model, the results are assured to be mesh size independent. Table 5 shows the elastic moduli calculated for HVF sample with epoxy resin in different mesh sizes.

Figure 6.

The periodic boundary circumstances, (a) tensile load and (b) shear load.

Table 5.

Mesh size for different model and prediction of elastic moduli for each model.

Model no	Mesh size (mm)		Number of elements	E11 (MPa)
Model no	Matrix	Yarn	Number of elements	E11 (MPa)
1	1	0.5	13,484	4808
2	0.7	0.25	55,262	5549
3	0.5	0.15	216,208	5691

Based on Table 5, there is a small difference between the results of models 2 and 3. So, mesh size for model 3 was chosen for meshing the unit-cells. Next, the embedded element technique was applied, considering the yarn parts as the embedded region and the matrix part as the host. However, to eliminate the volume redundancy caused by the embedded element technique,³⁰ the stiffness of the epoxy resin was subtracted from the stiffness matrix of the unidirectional composite yarns.

The representative unit cells of composite specimens are assumed as orthotropic and homogenous. Therefore, the stiffness matrix for an orthotropic substance is represented in equation (11) ³¹

[\bar{C_{i j}}] = [\begin{matrix} C_{11} & C_{12} & C_{13} & 0 & 0 & 0 \\ C_{21} & C_{22} & C_{23} & 0 & 0 & 0 \\ C_{31} & C_{32} & C_{33} & 0 & 0 & 0 \\ 0 & 0 & 0 & C_{44} & 0 & 0 \\ 0 & 0 & 0 & 0 & C_{55} & 0 \\ 0 & 0 & 0 & 0 & 0 & C_{66} \end{matrix}]

(11)

For the homogenous composite materials, the association between average strain and stress is

{\bar{σ}}_{α} = C_{α β} {\bar{ϵ}}_{β}

(12)

where

{\bar{σ}}_{α}

and

{\bar{ϵ}}_{β}

are average stress and strain and

C_{α β}

is the stiffness matrix of the composite. It is possible to compute the stress field

σ_{α}

(

α, β = 1,2,3)

, whose average gives the required components of the elastic matrix, one column at a time, as³²

{\bar{σ}}_{α} = \frac{1}{V} \int_{V} σ_{α} (x 1, x 2, x 3) d V

(13)

{\bar{ϵ}}_{β} = \frac{1}{V} \int_{V} ϵ_{β} (x 1, x 2, x 3) d V

(14)

C_{α β} = \frac{{\bar{σ}}_{α}}{{\bar{ϵ}}_{β}}

(15)

Where V represents the unit-cell’s volume. Thus, a python code was written to calculate average volume stress and stiffness matrix components based on equations 13–15.

At the macro model, a 3D cylinder geometry regarding the dimensions of the experimental sample was created. The elastic constants that were extracted from the meso model were assigned to the macro model. To simulate the torsion test, all degrees of freedom of one side were fixed and a torque load was applied to another side. The meso model was meshed using C3D8R element type in ABAQUS/Standard element library (an 8-node linear). Figure 7 shows the applied load and the macro model after mesh generation.

Figure 7.

Mesh generation on the unit cell.

Result and discussion

Figure 8 shows Torque- Revolution curves for composite samples with two different matrices. (2π radians becomes one revolution). It should be noticed that the average values were used for Figure 9.

Figure 8.

Loading and mesh generation on the macro model.

Figure 9.

Torque-Revolution for composite samples with (a) polyester resin and (b) epoxy resin.

According to Figure 8, composites with epoxy matrix show more torsional strength and revolution in comparison with composites with the polyester matrix. Moreover, the stiffness of the composites with the epoxy matrix is more than composites with the polyester matrix. It is obvious that the reason for this phenomenon is the high young modulus of epoxy resin. Furthermore, the increasing volume fraction of the fibers leads to more torque is needed to apply in order to fail the composite. In order to increase the volume fractions of the fiber in the composite structure, the orientation angle of weft and warp yarn should be changed during the fabrication process. Change the orientation angle of weft and warp yarns causes to align a greater number of fibers through the applied load. Therefore, a greater number of fibers contribute to reinforcing the composite and eventually improves the torsional strength. The shear stress of the composite sample under torsion load can be calculated as follow.³³

τ = \frac{T c}{J}

(16)

where T is torque, c is the radius, and J is polar moment of inertia of the composite sample. T also can be obtained by equation 17.³³

T = \frac{G J θ}{L}

(17)

where G is shear modulus,

θ

is angle of twist, and L is the length of the composite sample. So, increasing the fiber volume fraction leads to an increase in the shear modulus of the composite. The value of the torque has a straight relation with the shear modulus. Therefore, the torque is increased and the torsion strength of the composite will be increased in samples with a high volume fraction of fibers.

According to Figure 8, torque – revolution curves for the polyester resin is linear until the failure point. But, for epoxy resin, curves show a minor nonlinear behavior near the failure point. The reason of this phenomenon is related to the bonding strength between glass fibers and matrix. It seems the glass fibers have strong bonding with epoxy which leads to crack does not grow straightly and fibers distribute cracks in interface area.³⁴ However, it can be found that this bonding for glass fiber and polyester resin is not stronger than glass fiber with epoxy. So, a linear behavior can be observed until the failure point. Table 6 indicates the outcomes of the torsion test for all samples.

Table 6.

Experimental test results.

Sample	Maximum torque (N.mm)	Torsional strength (KPa)	Maximum revolution	Standard deviation
LVF- Polyester	3.65	34.97	0.136	0.69
HVF- Polyester	4.94	47.34	0.145	1.76
LVF- Epoxy	6.95	66.60	0.17	1.41
HVF- Epoxy	8.48	81.26	0.2	1.3

During the torsion test, extreme shear stress is applied to the composite. Based on observations from the test, in the initiation point of failure, cracks appeared through the composite that shows the matrix damage. Afterward, transverse and shear stress from the torsional load cause to damage occurs on fibers. The higher modulus of glass fiber than matrices creates a stress transfer near the fibers.³⁵ Thus, crack propagation through the various directions is more dominant than crack propagation mainly in one direction. High fiber volume fraction increases the crack distribution within the composite and plastic behavior of the composite.³⁵ The fiber orientation of the NC3DOW fabric in different directions contributes to stress transfer better than unidirectional composite. Eventually, by increasing the torsional load, the cracks propagate through the composite and failure is occurs on the matrix and fibers. Figure 9 shows the composite after a fracture.

In order to analyze the failure mechanism of the composite, the fracture surface was observed using a scanning electron microscope (Figure 10).

Figure 10.

The composite after fracture for low volume fraction with epoxy resin.

According to Figure 10(a), once a torsional load is applied to the composite, the weft yarns are deformed and aligned through the applied load. These yarns resist external load until the fracture occurs within the composite and yarns are damaged. Figure 10(b) shows a crack that is propagated within the impregnated yarn and the matrix, and fiber failure could be observed.

As was mentioned, a multi-scale finite element model was applied to predict the torsional behavior of the composites. Figure 11 and Figure 12 show stress contours for matrix and fabric in meso scale.

Figure 11.

Scanning electron micrographs of fractured surfaces of the composite, (a) composite failure and (b) fiber failure.

Figure 12.

Stress contours for matrix and fabric of the model with high volume fraction of yarn, (a) under tensile load through the first direction, (b) under tensile load through the second direction and (c) under shear load (unit: MPa).

As can be seen in Figure 11 and Figure 12, the yarns that align through load direction have a significant role in the improvement of the composite’s mechanical features. For instance, when a tensile load is applied to the composite in the x direction, the Z yarns and straight segment of warp yarn which is aligned through the tensile load are under more stress than other components. Von-mises stress is a criterion for the stress concentration and design in a structure. This stress in a 3D space could be obtained by the following formula.³⁶

σ^{'} = \sqrt{\frac{{(σ_{x} - σ_{y})}^{2} + {(σ_{x} - σ_{z})}^{2} + {(σ_{y} - σ_{z})}^{2} + 6 (σ_{x y}^{2} + σ_{x z}^{2} + σ_{y z}^{2})}{2}}

(18)

where

σ_{x}

σ_{y}

, and

σ_{z}

are normal stresses through x, y, and z directions, respectively.

σ_{x y}

σ_{x z}

, and

σ_{y z}

are shear stresses. Based on Von-mises stress, it can be determined that during the load process which area is critical in terms of stress concentration and change the fabric structure to reduce this issue. In Figures 11 and 12 the areas that the orientation of yarns is changed a stress concentration can be observed. Yarn curvature leads to reduce the reinforcing role of the yarn and a stress concentration occurs within the matrix in these areas. Once a tensile load is applied through the x-direction, straight yarns (Z yarns) resist maximum stress due to their orientation through the load direction. However, the stress concentration can be observed in the sections that the direction of warp yarns is changed (Figure 11(a) and Figure 12(a)). This phenomenon can be observed for tensile load through the y-direction that maximum stress occurs on the weft yarns. On the other side, the stress concentration on the matrix can be observed in the areas that the orientation of the warp yarns is changed (Figure 11(a) and Figure 12(a)) The coefficients of the stiffness matrix were obtained for each composite by Python code. The stiffness matrix for each sample is presented in Table 7.

Table 7.

Predicted stiffness matrices for low and high-volume fraction with epoxy and polyester matrix.

Composite sample	Stiffness matrix (GPa)
LVF- Polyester	$C_{i j} = [\begin{matrix} 10.296 & 3.079 & 3.132 & 0.000 & 0.000 & 0.000 \\ 2.515 & 4.321 & 2.238 & 0.000 & 0.000 & 0.000 \\ 2.516 & 2.539 & 4.323 & 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 3.414 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 2.012 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 0.000 & 2.983 \end{matrix}]$
HVF- Polyester	$C_{i j} = [\begin{matrix} 10.886 & 3.998 & 4.045 & 0.000 & 0.000 & 0.000 \\ 2.602 & 4.702 & 2.563 & 0.000 & 0.000 & 0.000 \\ 2.609 & 2.567 & 4.709 & 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 4.331 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 3.075 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 0.000 & 3.012 \end{matrix}]$
LVF- Epoxy	$C_{i j} = [\begin{matrix} 11.502 & 3.256 & 3.307 & 0.000 & 0.000 & 0.000 \\ 2.662 & 5.042 & 2.695 & 0.000 & 0.000 & 0.000 \\ 2.664 & 2.703 & 5.041 & 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 7.234 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 4.573 & 0.000 \\ 0.000 & 0.000 & 0.000 & 0.000 & 0.000 & 4.255 \end{matrix}]$
HVF- Epoxy	$C_{i j} = [\begin{matrix} \begin{matrix} 12.637 & 4.286 & 4.312 \\ 2.843 & 5.129 & 2.807 \\ 2.867 & 2.847 & 5.116 \end{matrix} \begin{matrix} 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 \end{matrix} \\ \begin{matrix} 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 \\ 0.000 & 0.000 & 0.000 \end{matrix} \begin{matrix} 8.369 & 0.000 & 0.000 \\ 0.000 & 5.153 & 0.000 \\ 0.000 & 0.000 & 5.159 \end{matrix} \end{matrix}]$

The stiffness matrices which were shown in Table 7 were utilized for the macro model. Stress contours of the macro model under a torsional load for high volume fraction epoxy composite are presented in Figure 13.

Figure 13.

Stress contours for matrix and fabric of the model with low volume fraction of yarn, (a) under tensile load through the first direction, (b) under tensile load through the second direction and (c) under shear load (unit: MPa).

To evaluate the accuracy of the numerical model, the torque-revolution curves of the FE model were compared with experimental results. The torque-revolution curves for numerical and experimental results are shown in Figure 14.

Figure 14.

Stress contours of HVF-epoxy sample in the macro scale (unit: MPa).

The results revealed that the proposed modeling approach can acceptably predict the composite’s behavior for the linear segment under the torsional load. Once the value of revolution is increased, more deviations can be observed between experimental and numerical results. In this study, FE modeling of linear behavior of the composites was considered and there is not an attempt to predict non-linear behavior of the composites. Table 8 shows a comparison between numerical and experimental outputs at 0.05 revolution that linear behavior can be observed until 0.05 revolution for all samples.

Table 8.

Comparison between experimental and numerical results at 0.05 revolution.

Sample	Experimental torque (N.mm)	Numerical torque (N.mm)	Error (%)	Experimental Shear modulus (GPa)	Numerical Shear modulus (GPa)	Error (%)
LVF-Polyester	1.49	1.41	5.3	3.19	3.41	6.8
HVF-Polyester	2.01	2.11	4.9	4.07	4.33	6.3
LVF-Epoxy	3.15	3.31	5.0	6.74	7.23	7.2
HVF-Epoxy	3.73	3.97	6.4	7.98	8.36	4.7

Table 8 shows that the proposed model could predict linear behavior of the composites under torsional load and the error values for all samples are under 8%. This model can be applied for the elastic behavior of the composite and to predict the failure and nonlinear stages, more supplements codes will be needed to add to the model. However, according to Figure 15, it seems that the stiffness of the numerical model is more than the experimental results. During the fabrication process, some fibers can be damaged because fibers are under tensile and bending loads. This issue reduces the mechanical properties of the fabric and the stiffness of the composite. The fiber damage during the fabrication process reduces the yarn strength that leads to reduce the composite strength. Moreover, the cross section of the yarns was assumed as a circular shape which is not perfectly circular. Cross section of yarns changes the polar moment of inertia that this fact changes the shear stress and torsion strength of the composite. So, this assumption can make an error in numerical results. Besides, some void can be created during the fabrication process which can reduce the mechanical properties of the composite. The presence of void in the composite is a factor for stress concentration which is the start point for crack propagation within the composite.

Figure 15.

Comparison between torque-revolution curves of experimental and numerical results for low and high-volume fraction with epoxy and polyester matrix.

Conclusion

This paper is an effort to investigate the torsional behavior of NC3DOW composite experimentally and numerically. In this study, two different volume fraction composites were fabricated with polyester and epoxy resins. The experimental results showed that using epoxy resin improves torsional strength in comparison to polyester resin. Moreover, the composites which were produced by polyester resin showed a brittle failure in comparison to epoxy resin. This phenomenon shows that the bonding strength between glass fibers and epoxy is more than glass fibers and polyester. The high bonding strength leads to cracks are distributed in different areas and a nonlinear behavior can be observed near the failure point of the composite. Furthermore, increasing the volume fraction of fibers leads to improve torsional behavior of the composite in the same matrix. The torsional strength for high and low volume fraction composite with epoxy matrix was 81.26 and 66.60 MPa, respectively. Moreover, the torsional strength for high and low volume fraction composite with polyester matrix was 47.34 and 34.97 MPa, respectively. In the composite with a high volume fraction of fiber, a high number of fibers contributes to preventing the crack growth continuously and distributes cracks within the composite. Therefore, the torsional strength of the composites with high fiber volume fraction is more than the composites with low fiber volume fraction. During the failure process, some cracks occurred through the matrix, and by increasing torsional load the cracks are propagated within the fibers and failure is occurred in the composite. Besides, a multi-scale finite element model was applied to predict the torsional behavior of the composites. The error value between the numerical and experimental model for the linear regime of the torque-revolution was less than 7%. This output indicates that the proposed model capable to predict the torsional behavior of the composites in the linear section.

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

Hamid Reza Aghaei

Mehdi Varsei

Saeed Ajeli

Mehdi Kamali Dolatabadi

References

Bilisik

. Multiaxis 3D weaving: Comparison of developed two weaving methods (tube-rapier weaving versus tube-carrier weaving) and effects of bias yarn path to the preform properties. Fibers Polym 2010; 11: 104–114.

Hufenbach

Böhm

Kroll

, et al. Theoretical and experimental investigation of anisotropic damage in textile-reinforced composite structures. Mech Compos Mater 2004; 40: 519–532.

Mouritz

Bannister

Falzon

, et al. Review of applications for advanced three-dimensional fibre textile composites. Composites Part A: Applied Science Manufacturing 1999; 30: 1445–1461.

Hasani

Hassanzadeh

Abghary

, et al. Biaxial weft-knitted fabrics as composite reinforcements: A review. J Ind Textiles 2017; 46: 1439–1473.

Hessami

Alamdar Yazdi

Mazidi

. The effect of loop density on the tensile behavior of biaxial weft knitted composites using both experimental tests and numerical method. J Ind Textiles 2019; 51(1): 48–67.

Ansar

Xinwei

Chouwei

. Modeling strategies of 3D woven composites: a review. Compos Structures 2011; 93: 1947–1963.

Abounaim

. Process Development for the Manufacturing of Flat Knitted Innovative 3D Spacer Fabrics for High Performance Composite Applications, 2011.

Stig

Hallström

. Effects of crimp and textile architecture on the stiffness and strength of composites with 3D reinforcement. Adv Mater Sci Eng 2019; 2019.

Gürgen

Kuşhan

. High performance fabrics in body protective systems. In: Materials Science Forum. Trans Tech Publ; 2017, pp. 132–135.

10.

Minapoor

Ajeli

Salmani Tehrani

. Investigation into tensile strength of noncrimp three-dimensional orthogonal woven structure. J Ind Textiles 2019; 49: 200–218.

11.

Tan

Tong

Steven

, et al. Behavior of 3D orthogonal woven CFRP composites. Part I. Experimental investigation. Composites Part A: Appl Sci Manufacturing 2000; 31: 259–271.

12.

Karahan

Lomov

Bogdanovich

, et al. Internal geometry evaluation of non-crimp 3D orthogonal woven carbon fabric composite. Composites Part A: Appl Sci Manufacturing 2010; 41: 1301–1311.

13.

Karahan

Lomov

Bogdanovich

, et al Fatigue tensile behavior of carbon/epoxy composite reinforced with non-crimp 3D orthogonal woven fabric. Composites Sci Technology 2011; 71: 1961–1972.

14.

Wilkinson

Ruggles-Wrenn

. Fatigue of a 3D orthogonal non-crimp woven polymer matrix composite at elevated temperature. Appl Compos Mater 2017; 24: 1405–1424.

15.

Xuan

. Impact Resistance Study of Three-Dimensional Orthogonal Carbon Fibers/BMI Resin Woven Composites. Materials 2020; 13: 4376.

16.

Abdellahi

Hejazi

Hasani

. Investigation of flexural behavior of 3D textile reinforced concrete using both experimental tests and finite element method. J Sandwich Structures Mater 2018; 20: 578–594.

17.

Rostami

Zarrebini

Abdellahi

, et al. Investigation of Flexural Performance of Concrete Reinforced with Indented and Fibrillated Macro Polypropylene Fibers Based on Numerical and Experimental Comparison. Struct Concrete, 2020.

18.

Shekarchizadeh

Jafari Nedoushan

Dastan

, et al. Experimental and numerical study on stiffness and damage of glass/epoxy biaxial weft-knitted reinforced composites. J Reinforced Plastics Composites 2020; 40(1–2): 70–83.

19.

Gürgen

. Numerical modeling of fabrics treated with multi-phase shear thickening fluids under high velocity impacts. Thin-Walled Structures 2020; 148: 106573.

20.

Gürgen

. The influence of boundary condition on the impact behavior of high performance fabrics. In: Advanced Engineering Forum 2018. Trans Tech Publ, pp. 47–54.

21.

Zhai

Zeng

G-d

, et al. A multi-scale finite element method for failure analysis of three-dimensional braided composite structures. Composites Part B: Eng 2017; 110: 476–486.

22.

Zhao

Song

, et al. Multi-scale finite element analyses of thermal conductivities of three dimensional woven composites. Appl Compos Mater 2017; 24: 1525–1542.

23.

Zhong

Tran

LQN

Kureemun

, et al Prediction of the mechanical behavior of flax polypropylene composites based on multi-scale finite element analysis. J Materials Science 2017; 52: 4957–4967.

24.

Masoumi

Abdellahi

Hejazi

. Investigation flexural behavior of hybrid-reinforced layered filament wound pipes using experimental tests and numerical model. J Ind Textiles 2021: 15280837211034244.

25.

Mishra

. 3-Dimensional Weaving, 2008.

26.

McDonough

Dunkers

Flynn

, et al. A test method to determine the fiber and void contents of carbon/glass hybrid composites. J ASTM Int 2004; 1: 1–15.

27.

Hessami

Yazdi

Mazidi

. Investigation of tensile and flexural behavior of biaxial and rib 1 × 1 weft-knitted composite using experimental tests and multi-scale finite element modeling. J Compos Mater 2019; 53: 3201–3215.

28.

Shekarchizadeh

Abedi

Jafari Nedoushan

. Prediction of elastic behavior of plain weft-knitted composites. J Reinforced Plastics Composites 2016; 35: 1613–1622.

29.

Chamis

. Mechanics of composite materials: past, present, and future. J Composites, Technology Res 1989; 11: 3–14.

30.

Tabatabaei

Lomov

. Eliminating the volume redundancy of embedded elements and yarn interpenetrations in meso-finite element modelling of textile composites. Comput Structures 2015; 152: 142–154.

31.

Tong

Mouritz

Bannister

. 3D Fibre Reinforced Polymer Composites. Elsevier, 2002.

32.

Barbero

. Finite Element Analysis of Composite Materials Using AbaqusTM. CRC Press, 2013.

33.

Shigley

. Shigley's Mechanical Engineering Design. Tata McGraw-Hill Education, 2011.

34.

Zhang

Karger-Kocsis

Zou

. Synergetic effect of carbon nanofibers and short carbon fibers on the mechanical and fracture properties of epoxy resin. Carbon 2010; 48: 4289–4300.

35.

H-w

Gao

. Effect of fiber volume fraction on the flexural properties of unidirectional carbon fiber/epoxy composites. Int J Polym Anal Characterization 2015; 20: 180–189.

36.

Budynas

Nisbett

. Shigley's Mechanical Engineering Design. New York, NY: McGraw-Hill, 2011.

Torsional behavior of non-crimp orthogonal woven composite using experimental and numerical methods

Abstract

Keywords

Introduction

Materials and experimental procedure

Result and discussion

Conclusion

Footnotes

Declaration of conflicting interests

Funding

ORCID iDs

References