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Three phases in the tensile failure process of the laminated fabric: (a) fracture of several yarns; (b) propagation of damage; and (c) complete failure.
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This paper deals with the fracture failure analysis on plain woven laminated fabrics used in stratospheric airship structures. A series of uniaxial tensile and central slit tearing tests were carefully conducted on bias specimens, and the corresponding tensile and tearing properties, including failure mechanisms and material strengths, of a laminat...
Citations
... To our knowledge, several studies have worked with a practical approach to predict different types of strength: the ability of a material to withstand applied forces without breaking or tearing, tearing strength, which measures the resistance of a textile to tearing when subjected to a force that causes a material to rip apart [18][19][20][21][22][23][24]; puncture strength, which refers to the ability of a material to resist penetration by a sharp object without tearing or rupturing [25][26][27][28][29]; bursting strength, which refers to the ability of a material to withstand pressure without rupturing or bursting [30][31][32][33][34][35]; and finally, tensile strength, the maximum tensile (pulling) force that a material can withstand without breaking [10][11][12][13][14][15][16][17]. Our study focuses only on the tensile strength of 2D. ...
Fabric strength plays a crucial role in determining and influencing all other performance attributes of textiles. Therefore, considering the strength of the fabric becomes essential when choosing the appropriate textile for a specific purpose. This article presents an experimental study that focusses on the properties of 100% polyester fabrics. To conduct this study, we created ten fabrics with different weave structures, resulting in a total of 200 samples for tensile strength testing. Moving on to the second phase, we analysed the physical and constructional characteristics of the fabrics, including the number of warp and weft threads, warp and weft density, and weight. This analysis was carried out based on the weave structures. Additionally, we performed tensile strength tests in both warp and weft directions to examine the mechanical properties of the fabrics. Finally, a statistical analysis was performed to determine the impact of the weave structures on the tensile strength of the fabrics.
... Hence, the load-elongation curve shows the behaviour of bonded jute fabric where sharp fall (about 40%-50%) of load occurs due to breakage of fibre and, thereafter, stick-slip effect for continuous breakage and slippage of fibres. 32,33 In the case of both-sides laminated fabric, the support of aluminium foil from both sides facilitates the better contribution of fibres, reducing the fall of load in failure and making the remaining curve smoother due to controlled slippage of fibres ( Figure 16). Therefore, the role of aluminium foil in tensile behaviour is not very significant. ...
This study develops an impermeable and flexible sheet for food packaging using aluminium foil and jute web. A hot melt sheet is used for laminating foil with a jute web. A simple manufacturing process has been suggested. The effect of different process parameters has been studied and optimized. The optimized calendaring temperature (top/bottom), pressure, and speed are 150/120°C, 15 kPa, and 1 m/min, respectively. Preheating and three consecutive runs show higher tenacity. This hybrid sheet uses around 88% or 78% jute (by weight) in one and both side laminated sheets, respectively. The failure mechanism shows the role of fibre-to-foil bonding. The developed fabric is lighter and more cost-effective than jute woven laminated fabric. The packet from hybrid fabric is sufficiently strong and pliable with excellent barrier properties to use as a hygienic sheet for food packaging.
... Currently, there are a lot of experimental and theoretical studies on the in-plane tearing resistance, the tearing residual strength was commonly adopted as the tearing resistance index, although it is not a material constant but varies with initial crack length and specimen size. Chen et al. [7][8][9][10] systematically investigated the uniaxial and biaxial tearing performance of laminated fabrics using the central crack tearing test method, test variables include length and inclination of the initial crack, uniaxial loading rate, biaxial loading stress ratio, and material off-axis angle. Zhang et al. [11] and Chen et al. [12] studied the effect of material off-axis angle, crack length, and crack direction on single-edge crack tearing properties of airship envelope fabrics. ...
Tearing is the primary failure mode of tension membrane structures, and the tearing residual strength (TRS) is a crucial index for assessing the tear resistance of coated fabric membranes. This study aims to investigate the nonlinear variation characteristics of in-plane TRS of membrane material and its underlying mechanisms, using nonlinear fracture mechanics theory and numerical simulation. First, uniaxial central tear tests are conducted to demonstrate the nonlinear variation of TRS with crack length. Further, the modified linear elastic fracture mechanics model is used to deduce three different fracture modes that explain the nonlinear variation and highlight the potential size effect problem of TRS. To reveal the mechanism behind this nonlinear variation, a damage constitutive model for membrane materials is proposed based on the theory of continuum damage mechanics and the crack band model. Finally, numerical simulations are conducted to examine the impacts of initial crack length, inclination angle, specimen size, and crack position on TRS. The results indicate that the interaction between the crack-tip damage zone, stress concentration zone, and specimen boundary leads to the nonlinear variation and size effect of TRS in finite-size specimens. To eliminate the size effect of TRS, the specimen width should be at least three times the crack length. This study is expected to enhance the understanding of the tearing characteristics of fabric membrane materials and provides a reasonable assessment method.
... 4 In view of this, many researchers have developed different multilayer coated/ laminated fabric-based structures for airship envelope using a variety of high-performance fabrics such as Zylon®, Vectran TM , Dyneema®, and Spectra®, which have high strengthto-weight ratios. [8][9][10][11][12][13][14][15][16][17] Such high-performance fibers are capable of development of lightweight and high strength airship envelope materials. For example, Cao and Gao (2009) 9 have reported envelope materials developed with Zylon® woven fabric laminated with both Tedlar® and Mylar® films using PU adhesive for the purpose of weather protection and He-gas barrier. ...
In terms of communications and scientific observations, a stratospheric airship can be an effective alternative to the artificial satellites in Earth’s orbit. For an airship to float in the low air-density stratosphere, it must be designed with light, flexible, and strong materials. In the present study, we have designed and developed six different coated and laminated structures by using high-performance para-aramid fabric, polyvinylidene chloride (PVDC)-coated biaxially oriented polyethylene terephthalate (BOPET), and polyvinyl fluoride (PVF) films. The developed coated and laminated stratospheric airship structures demonstrate excellent performance even in the harsh environmental conditions such as very low atmospheric pressure (∼0.001 atm), extreme temperatures (80°C in the day and −80°C in the night;), high UV irradiation, and ozone as well as atomic oxygen. In order to analyze the effect of the harsh environmental conditions existing in stratospheric atmosphere on physico-mechanical properties such as tensile strength, tear strength, peel strength, and helium (He) gas barrier of the prepared laminate structures, they were evaluated after exposure in simulated accelerated artificial weathering conditions up to 400 h. The developed multilayered laminated structures exhibited superior He-gas permeability (0.04 L/m²/24 h), high tensile strength (>820 N/cm), and good tear strength (401–477 N/cm) with relatively low areal density (207–262g/m²). Furthermore, all the laminates also demonstrated very low degradation in mechanical properties, that is, 3%–8% in peel strength, 1%–3% in tear strength, and 1%–2% in tensile strength under artificial weathering conditions up to 400 h.
... Tear strength is one of the most important characteristics of fabrics' mechanical performance; in typical service situations, a fabric will generally fail by tearing [7][8][9]. A thorough understanding of the tearing behaviour and damage morphology is critical to allow the proper design of laminated fabrics for industrial applications [10]. The tearing behavior of fabrics by the trapezoid procedure has been the subject of several research works [11][12][13][14][15][16]. ...
Laminated fabrics are widely used in diverse industries because of their ability to adapt to many different functions. Understanding their tear force behaviour is critical to evaluate their serviceability. The tearing behaviour of laminated fabrics can be examined using high-speed imaging and analyzed using image analysis techniques. This technique is an attractive tool to elucidate the tearing behaviour of laminated fabrics. Through high-speed imaging it is possible to observe the tearing process on the fabric (e.g., yarns bearing the load before failure, yarn breaking behaviour) and membrane (e.g., pop-in crack length, crack propagation, formation of wrinkles, thinning) sides of the laminated fabrics to understand the tearing behaviour. In addition, this technique helps quantify different phenomena such as the membrane pop-in crack length, and crack wake bridging width by yarns. High-speed imaging analysis is a promising technique to visualize the tear phenomena in laminated fabrics.
... Meng et al. [17] compared the results of cut-slit orientation of Vectran V Rbased laminated fabric with four empirical equations and concluded that slits can be modelled. Based on the projection of the orientation of slit, equivalent slit length has been established in few studies [15,[18][19][20]. Therefore, higher the orientation angle, lower is the equivalent or effective tear length. ...
... Pressurised cylinder test. The pressurized cylinder test (Figures 3 and 4) was conducted on a cylinder (2 m length and 0.4 m diameter) with slit parallel to the longitudinal axis following the method adopted by previous researchers [8,20,21]. Maekawa's [20] method of pressurization was followed with slight modification so as to simulate the test conditions of bi-axial tear test described in the previous section. Fabric of appropriate size was taken, and a cut (30 mm) was made at an appropriate place. ...
... The pressurized cylinder test (Figures 3 and 4) was conducted on a cylinder (2 m length and 0.4 m diameter) with slit parallel to the longitudinal axis following the method adopted by previous researchers [8,20,21]. Maekawa's [20] method of pressurization was followed with slight modification so as to simulate the test conditions of bi-axial tear test described in the previous section. Fabric of appropriate size was taken, and a cut (30 mm) was made at an appropriate place. ...
An experimental investigation on tearing behaviour of a coated fabric used in aerostat/airship has been undertaken. The tear tests have been conducted on bi-axial set up and pressurised cylinder. Tear propagation was studied by inducing dynamic tear on a bi-axially stressed coated fabric through a falling dagger. The influence of traverse rates, 1–500 mm/min, on tear strength under uniaxial loading was also studied. Thiele’s empirical equation has been found to fit the data of bi-axial tests and cylinder tests. The instantaneous tear on a bi-axially stressed fabric when left under constant stress for some duration lead to failure of fabric at even 15% lesser than critical tear slit length in about 15 min. The tear strength of the coated fabric was found to be less at 1 mm/min traverse rate while remaining nearly constant for higher rates of traverse. The critical tear length not only depends upon inherent tear strength of material, diameter and pressure of envelope but also on the time for which the tear remains under creep.
... They proposed a new tearing strength prediction model based on the theories of fracture mechanics. Chen et al. [21][22][23] systematically studied the uniaxial and biaxial central tearing properties of airship envelope materials and considered factors such as the notch length, notch angle, off-axis angle, and stress ratio. They finally proposed formulas to predict the tearing strength with and without the off-axis angle based on the Griffith energy theory and Tsai-Hill criterion, respectively. ...
This report presents a new critical tearing strength prediction model, the modified stress field model. Firstly, the critical tearing strength of six coated fabrics is obtained using the single-edge notched tests. The results show that the warp and weft strength utilization of different coated fabrics is similar. Based on the test data, the prediction effects, parameter meanings, and basic properties of three models, namely Thiele’s empirical formula, the stress field model, and the modified stress field model, are discussed and compared. Then, the predicted results and properties of the three models in different crack ranges, specifically the small crack range, are compared, and their application scopes are verified. The two commonly used models lack the improved prediction effects in the small crack range that is provided by the modified stress field model. Finally, to reduce the workload while maintaining a certain accuracy, a crack combination of 3 mm + 15 mm is recommended, which is further confirmed using the root-mean-square error index. The prediction results of Thiele’s empirical formula and the modified stress field model under this crack combination are compared. The new model can still maintain good prediction effects even when extrapolating for small cracks using limited test data. Because of its precision and convenience, the proposed model may relatively facilitate the application of single-edge notched or uniaxial central tearing tests.
... In recent decades, many scholars have devoted themselves to investigating the effects of initial crack parameters on tearing strength and tearing behaviors of coated fabrics. Chen et al. 18,[24][25][26] conducted the comprehensive investigations on the central tearing behaviors of laminated fabrics from experimental study and analytical models and established the equivalent yarns' analytical model which could predict the entire damage process of central tearing test. In addition, Chen et al. also carried out the uniaxial and biaxial central tearing tests to analyze tearing behaviors of airship envelopes and discuss the effects of crack parameters on tearing behaviors and tearing strength. ...
... As shown in Figure 10(a), the yarns in the experimental result break on one side, yet the yarns on both sides rupture synchronously in the numerical result. This difference should be attributed to the inherent unbalanced structure of NCF composites in the production process of membrane material and asymmetrical clamping, 26 but in the FE model, the completely balanced structure and symmetrical clamping of studied material could be guaranteed. The tearing stress-displacement curves of the NCF composites with typical bias angles obtained from the numerical and corresponding experimental results are plotted in Figure 11, in which the solid and dashed lines represent experimental and numerical results, respectively. ...
To reveal the central tearing behaviors and propagation mechanisms of the architectural non-crimp fabric (NCF) composites with an initial crack, a microscopic finite element (FE) model was proposed and developed to simulate the tearing propagation process of materials in this paper. Firstly, the experimental program including the central crack tearing test of NCF composites and uniaxial tensile test of yarns was performed for gaining the material parameters. Secondly, a finite element (FE) model was developed and validated from the good agreement between numerical and experimental results. Furthermore, tearing damage mechanisms and failure performances of the NCF composites with an initial central crack were simulated and analyzed. Finally, the effects of initial crack length, yarn orientation, and arch curvature of weft yarn on mechanical properties were investigated in depth. The analysis and comparison results indicate that the NCF composite shows the unneglectable orthotropic characteristics, in which the initial crack length, yarn orientation, and arch curvature of weft yarn have the significant effects on the mechanical properties. This paper thus provides an adequately feasible and accurate FE model for the numerical simulation on the central tearing propagation behaviors of the NCF composites with an initial crack.
... Chen et al. [8] determined that tearing characteristics of PVDF coated bi-axial warp knitted fabrics vary greatly with the bias angles and W-shaped relationship between tearing strength and bias angle, with a local strength peak at 45 angle. In series of works Chen et al. showed significant influence of stress ratios, slit parameters, off-axis angles, loading speeds on failure performance and tearing strength of laminated fabrics used in airship structures [9][10][11]. The effects of different notch shape and size, loading rate and specimen's size on central tearing behaviours of PVC coated fabrics were studied in [12]. ...
This paper reports the comprehensive experimental study of the tearing behaviour of PES/PVC-coated architectural membranes exposed to different accelerated aging conditions. Coated fabrics intended as building envelopes are constantly exposed to the environmental impacts, therefore, it is important to determine the influence of these factors on changes of mechanical properties, and the tear strength was considered to be one of the essential characteristics associated with the life span of a tensioned membrane structures. An accelerated aging model was developed based on the analysis of the aging factors significantly relevant to the building operation. The effect of abrasion, higher temperature and humidity as well as set of these aging factors on tear performance were investigated. The results show that in most cases the tear strength of architectural membranes changes marginally within the limits after exposure to artificial aging. The biggest contributor to tearing changes was high temperature, which could be the dominant component in the aging model. The study provides a better understanding of tearing performance of PVC-coated fabrics in real environmental conditions.
... Chen et al. [20,21] and Wang et al. [22,23] carried out systematic experiments and theoretical studies on the tearing properties of airship envelope materials under uniaxial and biaxial central tearing tests. The effects of crack length, crack angle, off-axis angles, stress ratio, and tensile speed on the tearing strength of membrane materials were investigated, and several theoretical methods including the finite element method were used to fit the test results. ...
In this study, detailed uniaxial and biaxial central tearing tests of a type of PVC coated polyester fiber fabric for buildings were carried out. The characteristics of the damage morphology, the formation of the triangle area at the crack tip, crack propagation, and failure modes during the entire tearing process were studied. The influence of crack orientation, crack length, and load ratio on tearing behaviors were analyzed, and it was found that the two parameters of crack orientation and length could be combined into a single variable of the number of cutting-off yarns in the direction perpendicular to crack propagation. For the uniaxial central tearing test, four widely used theoretical models were used to fit the experimental results, which led to the conclusion that Thiele’s empirical formula was the most suitable theory for predicting the tearing strength of PVC fabrics. Finally, the strain of all yarns across the crack section before and at the moment of crack propagation was recorded by the DIC equipment, and the load borne by each yarn was calculated based on the uniaxial tension curve of this material. In this way, the strain and load distributions were obtained for the first time, from which it was observed that the maximum strain almost always concentrated in the del-zone at crack tips, and the number of cutting-off yarns significantly affected the strain distribution. Specifically, the more yarns were cut off, the more difficult it was for other yarns far from the crack to exert their load-carrying capacity.
