Tearing Force Research Articles

Preparing porcine lens to mimic human lens capsule.

To develop a chemical method that makes porcine lens anterior capsule resemble human lens anterior capsule in tear force and perforating force. Beijing Tongren Hospital, Beijing, China. Experimental study. Porcine eyes were divided into groups, and reagents (0.9% physiological saline, 0.1% sodium hypochlorite, 0.3% sodium hypochlorite, and 0.5% sodium hypochlorite) were injected into the anterior chamber, respectively, recorded as Groups A, B, C, and D, respectively. A senior physician collected each group of anterior capsules after performing continuous circular capsulorhexis and assessing the anterior capsule's tearing and perforation forces. An additional group, which consisted of human lens anterior capsules taken in the operating room from patients with cataract, recorded as Group E. A tensile system was used to measure each sample's tensile force. A significant difference was found between Group A and any other group in maximum tensile force and average tensile force in both transverse and longitudinal directions. No significant difference was found between any 2 groups from Group B to Group E. According to the surgeon's assessment, the tear force characteristic of the porcine lens anterior capsule treated with 0.1%, 0.3%, and 0.5% sodium hypochlorite solution was similar to that of the human lens anterior capsule. Porcine lens capsule treated using this method can be used for training of new surgeons. The porcine lens anterior capsule treated with 0.5% sodium hypochlorite, which results showed most resembled human lens anterior capsule, can be used for robotic training.

Moisture barriers used in firefighters' protective clothing: Effect of accelerated ultraviolet radiation aging on their mechanical and barrier performance

AbstractFirefighters rely on their protective clothing as a second skin to perform their job. In the middle of this multilayered protective garment, the moisture barrier plays a vital role in preventing liquids to enter while allowing perspiration to escape. This research delves into the impact of accelerated ultraviolet (UV) aging on the performance of firefighter protective clothing moisture barriers, focusing on tear force retention, water vapor transmission rate (WVTR), and wetting via apparent contact angle. Changes in the tearing behavior and reductions in the tear force and tearing distance were observed after aging. Additionally, a reduction in WVTR was found for all the moisture barriers, due to pore closure in the ePTFE/FR PU membrane. In terms of water repellency, the base fabric side of one moisture barrier experienced a transition from hydrophobic to superhydrophilic potentially due to the degradation of the water‐repellent finish. The investigation also revealed that, due to the screening effect by the outer shell fabric, only a low percentage of UV radiation received by the turnout gear, less than 2% in the UVA range, may reach the moisture barrier. These results indicate the need to consider realistic exposure scenarios when assessing moisture barrier service life.

New feeding mechanism to enhance the properties of wrapped elastic composite yarn and denim fabrics thereof

In light of the recent technological advancements in composite yarns with multicomponent cores, also known as dual core spun yarns, their utilisation in the textile industry has become widespread. A V-grooved roller is employed to enhance the feeding of multicomponent cores. In this context, diverse composite yarn designs with varying feeding mechanisms can be employed to optimise yarn performance. This study presents an alternative feeding mechanism utilising a W-grooved roller for commercial use in composite yarn production. To achieve this, dual core yarns and wound elastic composite yarns (filament feeding varies with the sheath cotton fibre with elastane in the centre wrapped on the right and left side) were produced using a modified ring spinning system with different parameters. Denim fabrics were then produced using these composite yarns as weft yarns. The results demonstrated that the wrapped elastic composite yarns with left and right filament core positioning exhibited superior yarn properties in terms of strength, elongation at break, evenness and hairiness. Furthermore, denim fabrics made with wrapped elastic composite yarns exhibited superior breaking load and tearing force results on weft basis. These fabrics also exhibited lower growth, defined as the percentage of the fabric returning to its original length after tensile stress removal.

Moisture barriers used in firefighters' protective clothing: Effect of accelerated hydrothermal aging on their mechanical and barrier performance

AbstractFirefighters' protective clothing rely on moisture barriers to safeguard against liquid ingress while enabling sweat evaporation for comfort and safety. However, these moisture barriers can degrade over time, jeopardizing firefighters' safety. Existing evaluation methods, primarily visual inspection, are inadequate for assessing moisture barrier integrity in service. This study examines the effect of accelerated hydrothermal aging on the tear force, water vapor transmission rate (WVTR), and apparent contact angle in three moisture barrier models used in firefighter protective clothing. The moisture barriers studied varied in composition, structure, and base fabric fiber content. Results revealed that moisture barriers' responses to aging are influenced by factors, such as fabric structure, adhesive configuration, finish, and the presence of additional coatings. The hardening of the adhesive layer between the ePTFE membrane and the base fabric was observed in two of the moisture barriers, leading to a slight tear force reduction. Two of the moisture barriers also experienced crack and pit formation on the membrane side, which affected the WVTR. The water‐repellent finish on the fabric side degraded in one moisture barrier. Understanding these complex behaviors is essential for predicting the long‐term moisture barrier performance and enhancing firefighter safety.

"Inverted flap rhexis" - Salvation of intumescence.

Intumescent cataract can be a challenge even for an experienced surgeon, particularly for creating a continuous curvilinear capsulorhexis (CCC) because of increased endolenticular pressure. CCC in white intumescent cataract is associated with increased risk of extension of rhexis margin leading to radial tear or biradial extension causing "Argentinian flag sign" and associated complications. We describe a novel technique for CCC, in which we manipulate the vector forces acting in creating a capsulorhexis. After making a mini CCC, a flap is raised and then inverted under the rhexis margin and CCC is done by keeping the flap inverted using shearing and tearing forces, keeping the direction of force down and toward the center in a curvilinear fashion. It is a new surgical technique to perform a successful and safer CCC in intumescent cataract with consistent outcome.

Integrated Plug High-Strength Geocell Reinforcement in Foundation Design for Square Footing

This paper develops an analytical model to calculate the ultimate bearing capacity of the integrated plug high-strength geocell (IPGC)-reinforced foundation under a square footing. The high strength and stiffness of the geocell wall and the typical failure of the integrated plug-in joint tearing were considered. The ultimate bearing capacity of the IPGC-reinforced foundation was calculated in two separate parts. The ultimate bearing capacity of an unreinforced foundation was calculated using the modified Terzaghi equation. The increased bearing capacity of the IPGC was calculated as the function of the tearing force of the geocell wall, the height and the diameter of a geocell, the empirical static earth pressure coefficient, and the vertical additional stress coefficient under uniformly distributed rectangular loading. The results showed that the maximum error between the experimental and the theoretical results is less than 18%. The ultimate bearing capacity of IPGC-reinforced foundations decreases with larger geocell diameters. When the diameter of the geocell exceeds 1.8 times the foundation width, the confinement effect of IPGC becomes negligible. The findings of this study offer a robust analytical equation for predicting IPGC-reinforced foundations, along with valuable insights into the efficacy of IPGC reinforcement in enhancing foundation stability.

Selection assessment of promising forms of natural Hippophae rhamnoides (Elaeagnaceae) populations and their offspring in the Kazakhstan Altai Mountains

Abstract. Vdovina TA, Isakova EA, Lagus OA, Sumbembayev AA. 2024. Selection assessment of promising forms of natural Hippophae rhamnoides (Elaeagnaceae) populations and their offspring in the Kazakhstan Altai Mountains. Biodiversitas 25: 1809-1822. This article presents the results of studying the genetic diversity of sea buckthorn, Hippophae rhamnoides L. in natural populations of the East Kazakhstan region. This made it possible to identify valuable forms based on which targeted breeding work was carried out. Selection work has shown that this species has a unique gene pool. As a result of the analytical selection of H. rhamnoides in the first, second, and third generations, promising seedlings were obtained: ´Podarok Bajtulinu Sh-9-81 (4-6) II´, ´Jubilejnaja Kotuhova T-2-82 (2-22) III´, ´Dolgozhdannaja ?5 (3-24) III´, ´Shetlastinka ?7 (2-24) III´, ´Nesravnennaja Sh-9-81 (3-27) III´, ´Krasavica Sh-9-81 (3-30) III´, ´Solnyshko Sh-12-81 (1-18) III´ with high yield, large fruits, long stalk and low fruit tearing force. Among the male plants, the following forms are distinguished: ´Gustoj Tuman T-2-82 (1-24) III´, ´Ljubimec T-17-82 (2-20) III´, ´Krasavchik K-8-82 (1-34) III´, ´Bogatyr' T-17-82 (2-20) III´ with high winter hardiness and pollen productivity. A scale has been developed for the force of fruit separation and the density of the “cob” for local forms. A selection achievement (variety) patent was received for the ´Jubilejnaja Kotuhova´ form. The next two forms (´Shetlastinka´ and ´Podarok Bajtulinu´) pass the state test for economic usefulness. The richest gene pool of sea buckthorn in the Altai mountainous country indicates its high heterogeneity.

Moisture barriers used in firefighters' protective clothing: Effect of accelerated thermal aging on their mechanical and barrier performance

AbstractMoisture barriers are an essential component in firefighters' protective clothing as they allow water vapor to exit and prevent liquids from entering into the garment. However, they may be sensitive to thermal aging. This study investigates the effect of accelerated thermal aging at temperatures between 95 and 240°C on three different moisture barriers used in firefighters' protective clothing. Variations in their tear force, water vapor transmission rate (WVTR), and apparent contact angle were observed after thermal aging. These variations were influenced by factors such as the base fabric structure, fiber content, adhesive characteristics, and presence of an additional flame‐resistant polyurethane coating on top of the expanded polytetrafluoroethylene membrane. Adhesive degradation and delamination were observed in one moisture barrier, whilst different extents of base fabric degradation occurred in all three of them, leading to tear force reduction. Depending on the moisture barrier and aging temperature, the membranes experienced crack formation or pore closure, which affected the WVTR. The water‐repellent finish on the fabric side degraded in two moisture barriers but was not affected in the other. These findings highlight the importance of considering the constitutive materials and the structure of moisture barriers to understand their aging behavior and improve firefighters' safety.

Quality Improvement of Pea Protein Isolate‐Based Film: Effect of Sodium Carboxymethyl Cellulose on Film

AbstractSodium carboxymethyl cellulose (CMC) is cross‐linked with pea protein isolate (PPI) to prepare pea protein isolate/sodium carboxymethyl cellulose (PPI/CMC) composite film by the diffusion method. The effects of the mass fraction of CMC on the mechanical properties and water resistance of PPI/CMC composite film are investigated. In the film containing 0.4% CMC, the water vapor permeability (1.43 × 10−7 g m (m2∙h∙Pa)−1) is significantly decreased, while the water contact angle value is elevated (55.76°). The tensile strength of the composite film is enhanced by 54.45%, while the elongation at break is increased by 23.30%. The film has excellent thermal stability and a homogenous structure. The remarkable changes may be attributed to new chemical interactions (hydrogen bonds) between CMC and PPI as revealed by Fourier transform infrared spectroscopy. Further, the composite film has great advantages in water resistance after comparison. The film is applied to the fresh bean skin, effectively blocking and reducing the tearing force between the fresh bean skin, and consequently easy separation after soaking in water for 20 min. Overall, the inclusion of CMC effectively solves the functional limitation caused by the hydrophilicity of PPI film, paving the way for its effective application as a novel edible packaging film in conventional foods.

Effect of crossing warp architecture on tear strength of 3D orthogonal woven T-shaped reinforcements

T-shaped textile composites reinforced by two-dimensional laminates and simple forms of three-dimensional reinforcements are susceptible to tear failure and delamination at the junction. To address these issues and enhance the tear resistance of composite T-joints, 10 types of crossing warp architecture based on three-dimensional woven orthogonal structures were designed, manufactured and characterized with the aim of optimizing the reinforcement architecture. The assessment of the in-plane mechanical behavior was carried out by a tensile tear load applied to the two flanges of the T-shaped reinforcements. The employment of crossing warp architecture effectively enhanced stiffness, tensile strength, and failure strain. Resistance to the failure of the reinforcement was increased as more crossing warp yarns were employed. To further optimize the crossing warp architecture for reinforcement development, the internal and external crossing arrangements were compared. The new finding was regardless of the crossing warp proportions, the external crossing warp led to a higher resistance to the tear force for the reinforcement than the internal crossing warp. The stiffness and tensile strength of the external crossing warp reinforcements exhibited notable improvement, with a maximum increase of 49.1% and 31.1% respectively, compared with that of the internal warp crossing counterparts. The findings in this research will be useful in manufacturing composite T-joints to tailor the reinforcement architecture with different crossing proportions and arrangements for meeting the required mechanical properties.

МОДЕЛЮВАННЯ НАПРУЖЕНО-ДЕФОРМОВАНОГО СТАНУ КУЗОВА ЖОРСТКО-КУПЕЙНОГО ПАСАЖИРСЬКОГО ВАГОНА

The article deals with the analysis of the stress-strain state of rigid-compartment passenger cars body of JSC Ukrzaliznytsia. Reliability and strength of passenger cars depend on a number of factors, among which one can note the features of the design, the properties of the materials used, the efficiency of the manufacturing processes, the level of technical maintenance in operation, the quality of repairs, etc. The fleet of passenger cars mainly consists of models that were designed and manufactured in the 70s and 90s of the last century. The resource of these cars is almost exhausted; they are obsolete both morally and physically. Research conducted by specialists of various industrial enterprises and scientific organizations was aimed at developing and improving methods for determining the ultimate resource of metal structures to ensure the possibility of extending the service life of passenger cars. Recently, questions regarding the calculation of bodies and other parts of cars have been solved with the help of software technologies, most of which are based on the finite element method. The basis of this method is the discretization of space, the formation of equations, the collection and matching, and the assessment of accuracy. Consideration of the physical properties of materials, boundary conditions, and interactions between different parts of the car are key aspects when applying the finite element method. Therefore, taking into account the actual wear and tear in operation, the analysis of the stress-strain state of the body will make it possible to reduce the material costs for the repair of the load-bearing body in the sense of the distribution of wear and tear force flows. Taking into account the actual wear and tear of the body of the passenger car allows you to determine the real condition and forecast its further operation. It helps not only to reduce repair costs, but also to increase the safety and reliability of the wagon. The ability to rationally distribute wear and tear power flows allows for high-quality and timely maintenance and repair, which affects the overall productivity and technical condition of the railcar fleet. The article deals with the analysis of the stress-strain state of rigid-compartment passenger cars body of JSC Ukrzaliznytsia. Reliability and strength of passenger cars depend on a number of factors, among which one can note the features of the design, the properties of the materials used, the efficiency of the manufacturing processes, the level of technical maintenance in operation, the quality of repairs, etc. The fleet of passenger cars mainly consists of models that were designed and manufactured in the 70s and 90s of the last century. The resource of these cars is almost exhausted; they are obsolete both morally and physically. Research conducted by specialists of various industrial enterprises and scientific organizations was aimed at developing and improving methods for determining the ultimate resource of metal structures to ensure the possibility of extending the service life of passenger cars. Recently, questions regarding the calculation of bodies and other parts of cars have been solved with the help of software technologies, most of which are based on the finite element method. The basis of this method is the discretization of space, the formation of equations, the collection and matching, and the assessment of accuracy. Consideration of the physical properties of materials, boundary conditions, and interactions between different parts of the car are key aspects when applying the finite element method. Therefore, taking into account the actual wear and tear in operation, the analysis of the stress-strain state of the body will make it possible to reduce the material costs for the repair of the load-bearing body in the sense of the distribution of wear and tear force flows. Taking into account the actual wear and tear of the body of the passenger car allows you to determine the real condition and forecast its further operation. It helps not only to reduce repair costs, but also to increase the safety and reliability of the wagon. The ability to rationally distribute wear and tear power flows allows for high-quality and timely maintenance and repair, which affects the overall productivity and technical condition of the railcar fleet.

Design of Performance Characteristics on Laser Treated Denim Fabric

The current paper covers an experimental study, mathematical modelling, and design optimization of the laser treatment process of denim fabrics. Laser fading is used in the finishing phase of garment production, unfortunately, it decreases fabric durability. Denim fabric is known as a cotton fabric but nowadays it is blended with other fibres to improve fabric properties. For this reason, the main purpose of this study was to test multicomponent fabric longevity after laser treatment. The knowledge from this study is used by garment production company. The tear force, abrasion resistance, and colour difference are considered as performance characteristics of laser treated denim fabrics subjected to maximization. To achieve the goals, novel, mathematical models were developed. In the preliminary tests, the design space was determined. The full factorial design of experiments was utilized in the experimental study and the values of the performance characteristics are measured. Based on the results of the experimental study the artificial neural network and Haar wavelet based mathematical models were developed to predict the behaviour of the tear force, abrasion resistance, and colour difference. The artificial intelligence-based multicriteria design optimization procedure is developed.

High-quality and efficient large-area copper removal utilizing laser-induced active mechanical peeling

Large-area copper layer removal is one of the essential processes in manufacturing printed circuit boards (PCB) and frequency selective surfaces (FSS). However, laser direct ablation (LDA) with one-step scanning is challenging in resolving excessive substrate damage and material residue. Here, this study proposes a laser scanning strategy based on the laser-induced active mechanical peeling (LIAMP) effect generated by resin decomposition. This scanning strategy allows the removal of large-area copper layers from FR-4 copper-clad laminates (FR-4 CCL) in one-step scanning without additional manual intervention. During the removal process, the resin decomposition in the laser-irradiated area provides the mechanical tearing force, while the resin decomposition in the laser-unirradiated area reduces the interfacial adhesion force and provides recoil pressure. By optimizing scanning parameters to control the laser energy deposition, the substrate damage and copper residue can be effectively avoided. In our work, the maximum removal efficiency with different energy densities, pulse duration, and repetition frequency are 31.8 mm2/ms, 30.25 mm2/ms, and 82.8 mm2/ms, respectively. Compared with the reported copper removal using laser direct write lithography technology combined with wet chemical etching (LDWL+WCE) and LDA, the efficiency improved by 8.3 times and 66 times. Predictably, the laser scanning strategy and the peeling mechanism are simple and controllable, which have potential in electronics, communications, and aerospace.

Effect of the Slit on the Mechanical Tearing Behavior of High-Density Polyethylene and Polyester Geocell Strips

Geocells are widely applied in numerous infrastructure constructions, like heavy-haul railways and ports. The mechanical tearing behavior of a geocell strip is crucial to the stability of the geocell-reinforced soil structures. At present, extensive studies have been conducted on the tensile characteristics of geocell strips, while limited research has been performed to investigate the post-damage mechanical tearing behavior of geocell strips. Meanwhile, there is also a lack of research on the comparison of performance of strips before and after damage. In this paper, a series of trapezoidal tearing tests were performed on high-density polyethylene (HDPE) and polyester (PET) geocell strips. The tearing test results and failure mode of trapezoidal specimens with a slit were investigated, and the effect of the slit on the strength and deformation characteristics of the specimen were discussed by introducing the “damage ratio of tearing force (RTF)” and “damage ratio of tearing displacement (RTD)”. In addition, the mechanical tearing behavior of HDPE and PET trapezoidal specimens was also compared. The test results indicated that the failure mode of HDPE and PET specimens subjected to tearing force was ductile and brittle failure. The strength and deformation characteristics of post-damage HDPE and PET trapezoidal specimens decreased. The slit had a significant impact on the tearing displacement of HDPE and PET specimens, especially the post-peak tearing displacement. The post-peak tearing displacement of HDPE was 10.99 times that of PET. The peak tearing force of the HDPE specimen without the slit was about 1.61 times that of specimen with the slit. Before local tearing, the peak tearing force of the PET specimen without the slit was about 3.27 times that of the specimen with the slit. The strength damage to the HDPE and PET geocell strips caused by the slit was 38.0%, and 69.46%. The impact of the slit on the tearing force of the PET specimen was greater than that of the HDPE, and was 1.82 times for the HDPE. This study can enhance our understanding of the mechanical tearing behavior of the geocell strip after damage and develop effective mitigation measures.

Flexible and Robust Triboelectric Nanogenerators with Chemically Prepared Metal Electrodes and a Plastic Contact Interface Based on Low-Cost Pressure-Sensitive Adhesive.

Triboelectric nanogenerators (TENGs) are devices that can harvest energy from mechanical motions; such devices can be used to power wearable sensors and various low-power electronics. To increase the lifetime of the device, scientists mainly use the method of making TENG in a hard skeleton to simplify the complex possible relative movements between two triboelectric parts. However, the hard skeletons cannot be embedded in soft and lightweight clothing. To make matters worse, the materials used in the garments must be able to withstand high mechanical forces when worn, such as the pressure of more than 100 KPa exerted by body pressure or everyday knocks. Notably, the TENGs are usually made of fragile materials, such as vacuum-evaporated metal electrodes and nano-sized coatings, on the contact interface; these electrodes and coatings often chip or wear off under the action of external loads. In this work, we succeeded in creating a thin, light-weight, but extremely robust garment-integrated triboelectric nanogenerator (G-TENG) that can be embedded in clothing and pass the water wash test. First, we chemically deposited a durable electrode with flexible properties for G-TENG using a novel technique called polymer-assisted metal deposition (PAMD). The as-formed metal electrodes are firmly bonded to the plastic substrate by a sub-10 nm adhesive polymer brush and can withstand a pressure of 22.5 MPa and a tear force of 0.7 MPa. We then removed the traditionally used fragile nanoparticle materials and the non-durable poly-dimethylsiloxane (PDMS) layer at the triboelectric interface, and then used a cost-effective, durable and slightly flowable pressure-sensitive adhesive to form a plastic contact interface. Such a soft plastic interface can ensure full contact of the triboelectric materials, which is excellent in complex environments and ultimately improves the power generation efficiency of the devices. The as-formed low-cost energy harvesting device could become an industry standard for future smart clothing.

Effect of GNPs and resin blend on tear resistance of 4D printed shape memory photopolymer composite

PurposeThe tear strength (Ts) is a significant property for any kind of soft polymeric material such as rubber, elastomer, viscoelastic material and its composites, to quantify the suitability of a material for any shape memory applications. Many times, the soft elastomeric polymer material has to be capable enough to deform to a maximum extent of displacement but at the same time, it has to withstand the maximum load without fail. Along with shape recovery properties (i.e. the ability to recover its shape from programmed to the original), the success of the shape memory cycle is mainly depending on its stiffness and strength. It has to resist tear during stretching (i.e. programming stage) as repeatedly subjected to deformation, and, hence, it is important to study the tear behaviour for shape memory polymers (SMPs) and their composites. The purpose of the work is to investigate the effect of parameters on Ts of 4D printed specimen using Taguchi method.Design/methodology/approachThe objective of the work is to tailor the Ts of SMPs by reinforcing the graphene nano particles (GNPs) in a blended photopolymer (PP) resin with flexible PP and hard PP resin. In this study, a total of nine experiments were designed based on the L9 orthogonal array (OA) using the design of experiments (DOEs). All the shape memory photopolymer composite’s (SMPPCs) specimens are fabricated using masked stereolithography (MSLA), also known as resin three-dimensional printing (R3DP) technique.FindingsSpecimens are tested using universal testing machine (UTM) for maximum tear force (Fmax) and displacement (δ) caused by tearing the specimen to evaluate the strength against the tear. The results showed that the Wt.% of resin blend highly influenced both Fmax and δ, while GNPs also had an impact on δ. The specimens are offering more tear resistance for those specimens blended with less Wt.% of flexible PP at the same time the specimens enable more δ for those specimens reinforced with 0.3 Wt.% GNPs at 10-s exposure time. The optimum combinations are A1, B1 and C3 for the Fmax and Ts and at the same time A1, B3 and C3 for δ.Research limitations/implicationsTo customise the tear resistance of SMPPCs using MSLA 3 D printing, this study suggested a blend of PP resins reinforced with GNPs. This opens up a new path for creating novel, inexpensive multi-functional 4-dimensional (4D) printed parts.Originality/valueThe use of flexible PP and hard PP resin blends, fabricating the SMPPCs specimens using 3 D printed MSLA technology, investigating the effect of GNPs, resin blend and exposure time, optimizing the process parameters using Taguchi and the work were all validated using confirmation tests and regression analysis using test train method, which increases the originality and novelty.

Статистические зависимости влияния времени воздействия ультразвука на прочность и другие параметры сварного соединения полипропилена

Polypropylene is one of the most popular thermoplastic materials used in industry. To produce goods from this material, the ultrasonic welding method is often used. However, despite a large number of scientific papers, the influence of some parameters of the ultrasonic welding mode on the strength characteristics of polypropylene joints remains unstudied. The paper presents the results of experimental studies of contact spot ultrasonic welding of plates 3 mm thick made of 01003-26 grade polypropylene. The authors considered the process of gradual penetration of the ultrasonic tool working face into polypropylene to a depth equal to the total thickness of the welded plates. Statistical dependences of the depth of the tool face penetration into the material and the force of material separation on the ultrasound exposure time are obtained. The influence of the depth of the ultrasonic tool working face penetration on the tearing force of welded specimens is determined. A significant increase in the tearing force from 150 to 400 N was found at the tool penetration depth of more than 3.5 mm due to an increase in the nominal area of mutual mixing of the material between the welded plates caused by the flow of molten material into the gap. The authors proposed a hypothesis about the flow of the molten material in the direction opposite to the direction of penetration of the working tool by forming traveling Rayleigh waves. However, its confirmation requires additional studies of the influence of the ultrasonic welding mode parameters and the size of the gap between the parts to be joined on the rate of the molten material flow into the gap.

High-Speed Imaging Analysis of Laminated Fabric Tearing Behaviour

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.

Tissue damage force estimation in porcine small intestine from its elasticity.

Post-surgical complications are correlated to the surgeon's technical skill level. Thus, efforts are being put in finding ways to improve the surgeon's technical skills, such as not causing unwanted damage to tissues during surgery. In this study, we aim to investigate the possibility of estimating biological tissue damage, in view of preventing unwanted damage during surgery. A series of tensile tests were performed on porcine small intestinal tissue to determine the elasticity and the tearing force. The tissue was then microscopically observed to investigate the influence of fibrous protein configuration in the tissue's mechanical properties. The results from the tensile test showed that the fracture energy had a positive and linear correlation with the elasticity to the negative 0.5th power (R2 = 0.897), which was also suggested by an existing damage model for polymeric materials (Lake-Thomas model). The results from the microscopic observations also showed a resembling influence of fiber configuration on the elasticity as suggested in polymer mechanics (affine network model). We showed that the fracture energy had a correlation with the elasticity in porcine small intestinal tissues, which was also suggested in polymer mechanics, thus being a promising avenue toward the ability to estimate the maximum applicable force onto a biological tissue without causing damage during surgery. Attention should also be pointed, however, towards investigating the extent at which polymer mechanics and biomechanics overlap.

Microstructure and mechanical properties of refill friction stir spot welded joints: Effects of tool size and welding parameters

A novel refill friction stir spot welding (RFSSW) technique employing large-sized tools is proposed. The microstructure and mechanical properties of joints produced with a large-sized welding tool and a conventional tool are compared. The results show that the exit line resulting from the sleeve becomes longer with increasing the plunge depth, and the diameter of nugget increases with higher rotational speed for the joints produced by both conventional and novel tools. The plunge depth increases from 2.0 mm to 2.2 mm, then to 2.4 mm, which affects the hook defect to bend upwards, almost parallel to the lap interface, to bend downwards, respectively. The joints produced with the novel tool have a flat hook compared to the conventional tool. The microstructure evolution of the conventional and novel joints is similar. The tensile-shear and tearing forces measured of the novel joints are higher than those of the conventional joints for the same welding parameters. For conventional joints, the maximum tensile-shear and tearing forces are 8.6 ± 0.1 kN and 4.4 ± 0.2 kN, respectively. The maximum tensile-shear and tearing forces for novel joints are 10.9 ± 0.1 kN and 5.6 ± 0.1 kN, respectively. After the tensile-shear test, there are three modes of fracture, the upper-mixed, the lower-mixed, and the shear fracture one. The plunge depth has a pronounced effect on the fracture mode of joints.