Circular Cut Research Articles

Prediction and optimization of geometrical quality for pulsed laser cutting of non-oriented electrical steel sheet

Prediction and optimization of geometrical qualities, namely roundness of circular cut and kerf width of square cut, for pulsed laser cutting of non-oriented electrical steel are performed using deep neural network (DNN) and genetic algorithm (GA). Analyses using random forest method and response surface method show that laser power, pulse frequency, and cutting speed significantly affect the cutting qualities and are properly used as input variables in the prediction models. A real-coded GA is employed to determine the optimal DNN architecture, and the final DNN models are obtained through pre-training and fine-tuning processes. A binary-coded GA is utilized to determine the optimal combination of process parameters for generating the optimum geometrical qualities. The developed DNN-GA models show great ability in prediction of the roundness and the kerf width, as demonstrated by a very low mean absolute percentage error (≤2.60%) and a very high absolute fraction of variation (≥0.9972) for training, validation, and testing datasets. In addition, the performance of the DNN-GA models is evaluated by means of nine statistical criteria in comparison with other artificial intelligence based models, namely random vector functional link network (RVFL) and support vector machine for regression (SVR) integrated with equilibrium optimizer (EO) and grey wolf optimizer (GWO). The results indicate that the performance of the DNN-GA models is better than that of the RVFL-EO, SVR-EO, RVFL-GWO, and SVR-GWO models. The predicted optimal geometrical qualities of the DNN-GA models are verified by validation experiments in which a combination of the smallest roundness and kerf width is generated.

Hydrothermal performance improvement of an inserted double pipe heat exchanger with Ionanofluid

To meet the growing energy demand, double pipe heat exchangers (DPHEX), which are used in a variety of energy and thermal engineering applications, require improved heat transfer performance. In this study, a new class of surfactant-free Ionanofluid is formulated at three different concentrations of 0.01, 0.05 and 0.10 wt% and thermophysical and rheological properties are assessed. Zeta potential analysis is executed to assess the dispersion stability. An optimum concentration has been selected to investigate the hydrothermal performance of an insert fitted DPHEX at varying Re from 400 to 2000. The conventional twisted tape (TT) insert is modified by introducing different types of geometrical (triangular, rectangular, and circular) cuts on its surface. According to the Ionanofluid characterization, 0.10 wt % Ionanofluid has the highest thermal conductivity enhancement of 64% and heat capacity of 16.1% when compared to the base fluid, with a maximum enhancement in Nu of about 116–136% at varying Re. The rectangular-cut TT imparts highest heat transfer enhancement as the additional vortices is more intensive than other cut-inserts. Nevertheless, the value of PEC for the combination of Ionanofluid and RCTT insert, remaining between 1.61 and 1.68 over the entire range of Re, is greater than other combinations.

Compact perturbations of scalar type spectral operators

We consider compact perturbations S=DΛ+K of normal diagonal operators DΛ by certain compact operators. Sufficient conditions for K to ensure the existence of non-trivial hyperinvariant subspaces for S have recently been obtained by Foia\c{s} et al. in C.\ Foia\c{s}, I.B.\ Jung, E.\ Ko, C. Pearcy, \textit{J.\ Funct. Anal.} \textbf{253}(2007), 628--646, C.\ Foia\c{s}, I.B.\ Jung, E.\ Ko, C.~Pearcy, \textit{Indiana Univ.\ Math.\ J.} \textbf{57}(2008), 2745--2760, {C.\ Foia\c{s}, I.B.\ Jung, E.\ Ko, C.Pearcy}, \textit{J.\ Math.\ Anal.\ Appl.} \textbf{375}(2011), 602--609 (followed by Fang--Xia \textit{J.\ Funct. Anal} \textbf{263}(2012), 135-1377, and Klaja \textit{J.\ Operator Theory} \textbf{73}(2015), 127--142, by using certain spectral integrals along straight lines through the spectrum of S. In this note, the authors use circular cuts and get positive results under less restrictive local conditions for K.

On the theory of constitutive equations for composites with different resistance in compression and tension

The paper proposes a new approach to the construction of nonlinear constitutive equations for the description of elastic deformation of fibrous composites with different resistance in compression and tension. The framework of the approach is the generalized rheological method of constructing constitutive equations of the uniaxial stress–strain state. Transition to the tensor equations uses the hypothesis of existence of a special cone of all possible compression states in the space of strains. The cone structure is governed by the reinforcement pattern of a composite. When imposed with strains in the cone, the composite behaves as a linearly elastic medium, while beyond the cone, the composite is nonlinear, with higher stiffness conditioned by tension of high-modulus reinforcement fibers. It is highly critical that the constitutive equations obtained using this approach belong to the theory of hyperelasticity. The elastic potentials of stresses and strains are obtained for these equations, which guarantees implementation of fundamental principles of equilibrium thermodynamics. Application of the developed general theory is exemplified by construction of the constitutive equations for the plane stress state of a thin unidirectional fiber reinforced composite plate and for a multilayer plate with different-direction reinforcement of layers. Using the finite element method in combination with the initial stress method, the stress and strain patterns are analyzed in rectangular one-, two- and three-layer carbon fiber reinforcement polymer plates with a circular cut under the action of external stresses at the boundary.

Design of Band-Notched MIMO Antenna for UWB Applications

A compact ultra-wideband (UWB) Multiple-Input-Multiple-Output (MIMO) antenna with a notched band is presented. The proposed design consists of four unipolar UWB radiators, and these monopole radiators are placed perpendicular to each other to exploit polarization diversity, where the four-element ultra-wideband (UWB) Multiple-Input-Multiple-Output (MIMO) antenna is presented. The total size of the antenna is 60x60 mm2. The operating frequency of the antenna is 3.1–11 GHz with a return loss of less than 10 dB, except at the notched band of 4.9– 5.9 GHz. This antenna consists of an isosceles trapezoidal plate with a circular notch cut and two transitional steps as well as a partial ground plane. For UWB bandwidth enhancement techniques: use of a partial ground plane, and modify the gap between the radioactive element and ground plane technique, using steps to control the resistance stability and a notch cut technique. The notch cut from the radiator is too used to reduce the size of the plane antenna. The measured -10 dB return loss bandwidth for the designed antenna is about 116.3% (8.7 GHz). The MIMO antenna does not require any additional structure to improve insulation. The proposed antenna supplies an acceptable radiation pattern and relatively flat gain over the entire frequency band.

Верхнепалеолитические украшения из южной галереи Денисовой пещеры: коллекция 2021 года

This article presents a new collection of the Early Upper Paleolithic personal ornaments from layer 11 in the South Chamber of Denisova Cave. The collection contains items of several types: a flat round bone bead, pendants made of teeth of predators and ungulates with cutting and perforation, a pendant from a freshwater mollusk shell with a hole, a fragment of a bracelet, a ring and a pendant with cutting made of marble, a small flake from serpentine. As a result of the study, the technologies for ornament production were reconstructed, the main methods of their use were determined, and examples of ornaments reshaping for using according to a new function were recorded. The technology for the teeth pendants production included a short sequence of operations: obtaining blanks, processing by planing or scraping, applying circular cuts or perforating by drilling. The production of flat beads was carried out by cutting out elongated plates from the walls of the tubular bone of large mammals, preparing blanks by planing, cutting out preforms, biconical drilling and grinding. The finished pendants and beads were massively used to decorate clothes and as personal apparel. The technology for the production of ornaments from marble involved a short or longer sequence of actions. To create the most complex marble products, i.e. rings and bracelets, a similar technological sequence was used, including the selection and transportation of raw materials, perforation followed by boring of the resulting hole, grinding, and polishing. Rings and bracelets were used as apparel, and probably had a special status.

Infiltration-induced phreatic surface flow to periodic drains: Vedernikov–Engelund–Vasil’ev’s legacy revisited

An explicit analytical solution is obtained to an old problem of a potential steady-state 2-D saturated Darcian flow in a homogeneous isotropic soil towards systematic drains modeled as line sinks (submerged drains under an overhanging of a phreatic surface), placed on a horizontal impervious substratum, with a constant-rate infiltration from the vadose zone. The corresponding boundary-value problem brings about a quarter-plane with a circular cut. A mathematical clue to solving the Hilbert problem for a two-dimensional holomorphic vector-function is found by engaging a hexagon, which has been earlier used in analytical solution to the problem of phreatic flow towards Zhukovsky’s drains (slits) on a horizontal bedrock. A hodograph domain is mapped on this hexagon, which is mapped onto a reference plane where derivatives of two holomorphic functions are interrelated via a Polubarinova-Kochina type analysis. HYDRUS2D numerical simulations, based on solution of initial and boundary value problems to the Richards equation involving capillarity of the soil, concur with the analytical results. The position of the water table, isobars, isotachs, and streamlines are analyzed for various infiltration rates, sizes of the drains, boundary conditions imposed on them (empty drains are seepage face boundaries; full drains are constant piezometric head contours with various backpressures).

A novel method for analyzing working performance of milling tools based on reverse engineering

Aiming at solving the problems of small footage, easy skid and immovability of milling during the process of milling multistage fracturing ball seats by milling tools, and considering simultaneously the difficulties of establishing a full-sized simulation model of the milling tool due to the irregular structure and wide variety, a novel method for analyzing the working performance of milling tools based on reverse engineering was proposed to improve the working efficiency on the premise of construction safety. In this paper, a 3D scanning model of the MX97 milling tool was obtained through a 3D laser scanner, and a full-sized simulation model was established based on reverse engineering for finite element analysis. Besides, an experimental system for milling tools was developed to verify the simulation result. Also, the systematic analysis of the influence rule of working parameters on working performance based on the full-sized simulation model was performed, and a selection database of working parameters in the form of charts was established. The analysis results show that the error between simulation and experiment is only 9.9%, which verified the accuracy of the analysis method based on reverse engineering. The surface morphology of the workpiece after simulation and experiment are both circular cuts, and the bottom surface of the milling tool should be designed as an eccentric structure to avoid the zero point of cutting speed that affects the working efficiency. WOB and rotating speed of milling tools affect and interact with each other, which jointly determine the working performance of milling tools. It is necessary to comprehensively use the data from the selection database to accurately determine the working parameters to improve the working performance of the milling tool.

Designing conformal cloaks by manipulating structures directly in the physical space.

The method to elaborately design the refractive index profile in the lower Riemann sheet of Zhukovski transformation plays an important role in the performance of this kind of conformal cloaks. However, for most proposed schemes, the mathematical calculations are complex. Here, we propose a more convenient method to design conformal cloaks by manipulating structures directly in the physical space. The designed cloak only needs symmetrical metal boundaries filled with normal dielectrics (refractive index ranges from 1 to 2) in the 'circular branch cut', which would be more feasible for future experimental implementation. Numerical simulations are performed by using the finite element method to validate our theoretical analysis.

Cyclic performance of bolted end-plate RWS connection with vertical-slits

The reduced beam section (RBS) connections are widely used in construction buildings due to their desirable ductility and strength. The current reduced web section (RWS) connections are produced by a reduction in the beam web as circular or rectangular cuts or as horizontal slits. This article has proposed a new detail for the RWS bolted connection by creating vertical-slits in the beam web. The aim of this investigation is the evaluation of its cyclic performance in comparison with the conventional RBS connection. Two specimens, one with vertical-slits in the web (VS-RWS) and the other one with a radial-cut in the flange (RC-RBS), were experimentally tested and the results were compared. Moreover, numerical models were employed to evaluate the behavior of connections in detail. These two connections were able to move the plastic hinge region away from the column face, exhibit good hysteresis behavior, and satisfy the AISC requirements for special moment-resisting frames. The results also showed that the flexural capacity of the proposed VS-RWS connection is 10% higher than that of the conventional RC-RBS one, while their ductility and energy dissipation were almost the same. An important advantage of VS-RWS over RC-RBS is its ability to prevent the lateral-torsional instability. Besides, a numerical study was conducted to investigate the performances of various cut shapes RWS connections with certain overall dimensions and location of the cutting region in terms of hysteresis curves, rupture index and end-plate deformations.

Visual Control Law Tuning Using the JADE Algorithm Applied to Leaf Detection and Cutting

In the propagation of plant tissue in vitro it is necessary to obtain from the leaf a circular section cut. In order to achieve this type of cuts the visual feedback is used, allowing us to analyze the RGB planes to detect the green color and find the image centroid. In order to fulfill the cut objective a PD+ control is used with self-tuning based on the adaptive differential evolutionary algorithm JADE.

CUSTOMIZING AIRWAY STENT FOR MULTICENTRIC MALIGNANT AIRWAY OBSTRUCTION

TYPE: Abstract Publication TOPIC: Procedures PURPOSE: A middle-aged man with adenocarcinoma of sigmoid colon and solitary liver metastasis underwent neoadjuvant chemotherapy followed by hemicolectomy and hepatectomy. The cancer progressed and he developed endobronchial metastasis resulting in near-total obstruction of left main bronchus (LMB) and bilateral pulmonary nodules. METHODS: Laser photoresection of LMB tumor was performed followed by covered self-expanding metallic stent (SeMS). He received radiation and anti-angiogenic therapy. Six months later, he complained of worsening dyspnea and stridor. CT Thorax revealed complete occlusion of the distal end of stent with collapse of left lung. Rigid bronchoscopy revealed tumor in-growth through the stent; tumor at the main carina causing 70% obstruction of the right main bronchus (RMB), and a polypoidal mass arising from the right middle lobe bronchus. Tumor debulking was performed within the stent and at the carina with argon plasma coagulation (APC) and rigid forceps, and the polypoidal mass was removed with electrosurgical snare. The left limb of silicone Y stent was cut to accommodate the SeMS while another circular cut was made just beyond the take-off of the right limb. The right limb of Y stent was deployed into bronchus intermedius, the circular cut maintained aeration to the right upper lobe (RUL). Post procedural CXR showed re-expansion of the left lung with satisfactory position of the silicon and SeMS stents. RESULTS: Figure 1. Bronchoscopic images CONCLUSIONS: Complex Airway Obstruction interferes with airflow and insertion of airway stents provide relief and complement ablative techniques. Modification of stents may prove to be beneficial to these patients. CLINICAL IMPLICATIONS: Please refer above DISCLOSURE: No significant relationships. KEYWORDS: central airway obstruction, airway stent

Research of 3D weft-knitted fabrics designed to protect against mechanical risks and suitable for contact with skin

Eight different 3D weft-knitted fabrics, consisting of outer, binding, and inner layers, were designed and produced on E20 and E28 circular weft-knitting machines. First, in the outer layer, high molecular weight polyethylene multifilament yarns and steel wire (0.05 mm diameter), twisted with high molecular weight polyethylene multifilament yarns, were used because of their exceptional properties to resist the mechanical risks. Second, in the inner layer, hydrophobic polyester spun yarns were chosen for their suitability to be used in contact with skin. Finally, in the binding layer, synthetic elastic textured polyamide yarns were used to connect the outer and inner layers. Following the standard EN 388, diverse tests were conducted to determine the resistance of the developed 3D weft-knitted fabrics to mechanical risks, i.e., circular blade cut, puncture, abrasion, and tear. The analysis showed that the quantity of steel wire in knitted structure highly influences circular blade cut and abrasion resistance, and moderately influences tear resistance for all the investigated knitted fabrics. While a strong positive correlation between the quantity of steel wire and the puncture force was defined only for 3D fabrics knitted on an E20 circular weft-knitting machine. The findings of the research lead to the conclusion that the designed 3D weft-knitted fabric structures, where the outer layer ensures protection against mechanical risks, while the inner layer is designed for contact with skin, provide complex protection against diverse mechanical risks.

THE INFLUENCE OF HYDRO BLASTING ON THE EN-DURANCE LIMIT OF SPECIMENS WITH A CUT UNDER BENDING AND STRETCHING-COMPRESSION

The hydro blasting influence on an endurance limit of cylindrical specimens with circular cuts of a semicircular profile of 0,3 mm radius under bending and stretching-compression in a case of symmetric cycle has been examined. Specimens of 10 mm diameter for fatigue tests were made of steels 30ХГСА, 12Х18Н10Т, ЭИ961,45 and aluminum alloys В93, Д16Т.The influence of surface hardening on an endurance limit of specimens with cuts was valuated by two criteria: residual stresses on the concentrator surface and the average integral residual stresses calculated through the parts dangerous section surface layer thickness equal the critical depth of a non-propagating fatigue crack. 
 On results of residual stresses and specimens with cuts endurance limits determination its been stated that coefficients of surface hardening influence on an endurance limit increase under bending and stretching-compression by two criteria are approximately equal. Besides, the coefficient of the influence by the average integral residual stresses criterion changes within essentially lesser limits than the coefficient of the influence by the residual stresses on the concentrator surface criterion. So the average integral residual stresses criterion should be used for the evaluation of a surface hardening influence on an endurance limit of parts with concentrators.
 On an example of specimens within and without peening in a dangerous section its been shown that peening doesnt influence the endurance limit of a surface hardened part. The compressive residual stresses only influence the endurance limit of these parts.

Occurrence of Green Semilooper Chrysodeixis acuta Walker (Lepidoptera: Noctuidae) in Onion (Allium cepa L.) (Amaryllidaceae)

The occurrence of green semilooper, Chrysodeixis acuta Walker (Lepidoptera: Noctuidae) in onion was recorded for the first time from the Pune district of Maharashtra State of India. Weekly observations of the pest and its damage were made to assess the intensity of the caterpillar population and its impact to the onion crop. Early instar larvae of C. acuta feed by scraping the leaves, whereas the later instars make circular cuts in the leaves. The presence of large cuts and defoliation is a sign of infestation in onion. Since C. acuta is polyphagous, it may spread to onion crops in the region and cause significant damage to the crop. Therefore, further research is required to monitor its spread and ability to become a pest in onion.

Dual- Band Antenna for Wi-Fi and 5G Applications

In this communication, a circular patch antenna is reported for dual- band operation based on VIAs. Initially the patch is resonating at single band with Linear Polarization (LP), and the Circular Polarization (CP) is obtained by inserting semi circular cuts at the edges of circular patch. The second band is achieved by loading the vertical metallic VIAs along the circumference of the patch antenna. The reported antenna is working at 2.4 GHz (Wi-Fi) and 3.5 GHz (5G) bands with Return Loss Band Width (RLBW) of 4.83% and 10.37% respectively. The Axial Ratio (AR) bandwidth at 5G band is 2.38% (3.31- 3.39 GHz).

Dual- Band Antenna for Wi-Fi and 5G Applications

In this communication, a circular patch antenna is reported for dual- band operation based on VIAs. Initially the patch is resonating at single band with Linear Polarization (LP), and the Circular Polarization (CP) is obtained by inserting semi circular cuts at the edges of circular patch. The second band is achieved by loading the vertical metallic VIAs along the circumference of the patch antenna. The reported antenna is working at 2.4 GHz (Wi-Fi) and 3.5 GHz (5G) bands with Return Loss Band Width (RLBW) of 4.83% and 10.37% respectively. The Axial Ratio (AR) bandwidth at 5G band is 2.38% (3.31- 3.39 GHz)

EMIG Simulation Systems Construct Validation Trial: Laparoscopic Component

Study Objective Construct validation of the EMIG Laparoscopic Surgery Simulation System. Design A prospective, controlled cohort comparison. Setting Thirteen teaching institutions in the US and Canada and an AAGL Congress Patients or Participants 221 subjects who fit one of 4 categories of exposure to laparoscopic surgery and surgical simulation: 77 novices within 100 days of starting posgraduate year 1 (PGY-1); 71 within the first 100 days of starting PGY-3; 30 American Board of Obstetrics and Gynecology (ABOG) certified and no additional fellowship training (“Proficient”); 43 who had completed the two-year Fellowship in Minimally Invasive Gynecologic Surgery (FMIGS). Interventions Subjects were oriented to the simulation system and then tested under proctor supervision on the 5 EMIG laparoscopic exercises. These included the sleeve to peg transfer (L-1); the circular pattern cut (L-2); extracorporeal knotting (L-3); intracorporeal knotting (L-4); and a running suture (L-5). Time and accuracy scoring were entered electronically on site, but sessions were video recorded and study materials such as cutting and suturing targets were labeled and stored for subsequent review to optimize data quality. Measurements and Main Results Each exercise was timed, and a number of objective metrics recorded that reflected cutting and suturing accuracy and technique. Each exercise had a “time cap”; if a subject had not completed the exercise by the end of the allotted time, they were categorized “Did Not Complete” and the maximum time was entered for data analysis. Preliminary data analysis demonstrates that the novice group consistently demonstrated the poorest performance and the FMIGS cohort consistently the best. The PGY-3 and “Proficient” cohorts were generally similar to each other but each performed better than the PGY-1 group and well below the FMIGS group. Conclusion The EMIG Laparoscopic Simulation System can be used to distinguish amongst PGY-1, PGY-3, Proficient and FMIGS subjects. FMIGS-trained subjects consistently had the best results with almost no “Did not Complete” outcomes. Construct validation of the EMIG Laparoscopic Surgery Simulation System. A prospective, controlled cohort comparison. Thirteen teaching institutions in the US and Canada and an AAGL Congress 221 subjects who fit one of 4 categories of exposure to laparoscopic surgery and surgical simulation: 77 novices within 100 days of starting posgraduate year 1 (PGY-1); 71 within the first 100 days of starting PGY-3; 30 American Board of Obstetrics and Gynecology (ABOG) certified and no additional fellowship training (“Proficient”); 43 who had completed the two-year Fellowship in Minimally Invasive Gynecologic Surgery (FMIGS). Subjects were oriented to the simulation system and then tested under proctor supervision on the 5 EMIG laparoscopic exercises. These included the sleeve to peg transfer (L-1); the circular pattern cut (L-2); extracorporeal knotting (L-3); intracorporeal knotting (L-4); and a running suture (L-5). Time and accuracy scoring were entered electronically on site, but sessions were video recorded and study materials such as cutting and suturing targets were labeled and stored for subsequent review to optimize data quality. Each exercise was timed, and a number of objective metrics recorded that reflected cutting and suturing accuracy and technique. Each exercise had a “time cap”; if a subject had not completed the exercise by the end of the allotted time, they were categorized “Did Not Complete” and the maximum time was entered for data analysis. Preliminary data analysis demonstrates that the novice group consistently demonstrated the poorest performance and the FMIGS cohort consistently the best. The PGY-3 and “Proficient” cohorts were generally similar to each other but each performed better than the PGY-1 group and well below the FMIGS group. The EMIG Laparoscopic Simulation System can be used to distinguish amongst PGY-1, PGY-3, Proficient and FMIGS subjects. FMIGS-trained subjects consistently had the best results with almost no “Did not Complete” outcomes.

Analysis of heat transfer characteristics with triangular cut twisted tape (TCTT) and circular cut twisted tape (CCTT) inserts

Abstract The paper represents the numerical investigation of heat transfer characteristics in a pipe provided with twisted tape inserts is analyzed. The heat transfer was analyzed in a swirling flow conditions using CFD simulation. A commercial CFD package was used for analyze twisted tape for circular tube fitted with triangular cut twisted tape and circular hole cut twisted tape inserts. The twisted tape system allows a significant increase of convective heat transfer coefficient by introducing the swirl flow motion. The swirl flow motion provides greater heat transfer rate extracted from the solid surface of the tube. The depth of cuts for triangular cut 5 mm and depth of hole cut 5 mm twisted tapes were used for simulation generation. In this paper CFD analysis was used for enhancement of heat transfer rate of fluid of laminar flow. The experimental investigation were conducted in double pipe heat exchanger and these value of plain twisted tape, triangular twisted tape and circular hole cit twisted tape were taken for used simulation analysis. The performance of heat transfer rate was enhanced 1.1–1.3 times compared that the plain twisted tape and circular cut twisted tape. The data obtained from the simulation correlations for triangular cut twisted tape and circular hole cut twisted tape; and these data were correlated with plain twisted tape.

Comparison between tensile and damage analysis of hybrid jute/polypropylene needlepunched nonwoven geotextiles produced from untreated and alkali treated jute fibers

The tensile properties of virgin and mechanically damaged samples are investigated for hybrid needlepunched nonwoven geotextiles consisting of untreated Jute/Polypropylene (PP) and alkali treated Jute/PP fibers in defined weight proportions. The damages in nonwovens were induced by two types of mechanical damages (circular hole and horizontal cut) in the center of hybrid nonwovens tested in the cross-machine direction. It was found that the horizontal cut was more detrimental than circular hole in nonwoven geotextiles consisting of jute (both untreated and alkali treated) and polypropylene fibers, specifically when the nonwovens were tested in the cross-machine (preferential) direction. Furthermore, Jute/PP hybrid nonwoven geotextiles were found to be notch-sensitive in nature. The ratio of damaged area of untreated and alkali treated Jute/PP nonwovens at the maximum level of tensile strain to that of the area of corresponding Jute/PP nonwoven determined in the beginning was found to be higher in untreated Jute/PP nonwovens. Similarly, Poisson’s ratio of untreated Jute/PP nonwovens was also found to be higher in comparison to alkali treated Jute/PP nonwoven geotextiles. The initial region of non-linearity of stress–strain curves matched well with that of volumetric deformation for both damaged nonwoven geotextiles. Accordingly, the initial region of stress–strain curves of damaged needlepunched nonwoven can be modeled as a linear region with constant volume deformation.