Ultimate Breaking Strength Research Articles

PHYSICO-MECHANICAL PROPERTIES OF POLYMER MATRIX COMPOSITE MATERIAL REINFORCED WITH CARBONIZED CASSAVA BACK PEEL AND IRON FILLINGS

The use of natural particles as reinforcement in polymers has been a growing research area. This study aims to explore the use of cassava back peel (CCBP) and iron-fillings (IF), as reinforcement material in epoxy resin-based composite. Composite plates were prepared for the casting of the epoxy resin reinforced with CCBP and IF composites using a hand lay-up technique. The percentage compositions by weight of the CCBP varied between 0%-10 %, while that of IF was kept constant (5%). The physico-mechanical behaviours of CCBP-reinforced epoxy polymer composites were studied using ASTM standards. The density of the epoxy resin was improved by the reinforcements. The maximum density obtained was 1270 kg/cm3 for 5%CCBP epoxy composite. The percentage of water absorption improved by the addition of the filler with 5%IF10CCBP epoxy hybrid composite recording 30% water absorption. Conversely, the ultimate tensile strength (UTS) and breaking strength (BS) varied with the addition of the filler materials. 5%CCBP epoxy composite recorded 41.26 MPa for both UTS and BS. Meanwhile, percentage elongation decreased with the addition of the fillers showing that the composites became less ductile. The HBN of epoxy was improved with the addition of fillers. The composites can be applied to automobile dashboards.

Through the Forming Process of Femtosecond-Laser Nanotextured Sheets for Production of Complex 3D Parts

The use of ultra-short pulse lasers in the kW range, combined with an appropriate beam engineering approach, enables the achievement of high-throughput production of laser-functionalised surfaces. However, the manufacturing of complex parts still faces various challenges, such as difficulties in accessing regions with high aspect ratio shapes or intricate profiles, which often leads to the necessity of adapting the laser processing workstation to specific geometries. The forming process is a well-established technique for producing parts of any shape from metallic foils by imposing specific constraints. In this study, we aimed to assess the feasibility of producing laser-functionalised 3D complex products by the forming of laser-treated flat thin metallic sheets. Two-hundred micrometre-thick stainless-steel foils were textured with laser-induced periodic surface structures (LIPSS) through a roll-to-roll pilot line. First, we optimized the morphology of LIPSS. Subsequently, we conducted three types of mechanical tests on both laser-treated and untreated foils: standard tensile tests, fatigue tests, and cruciform specimen tests. We measured and compared parameters such as ultimate tensile strength, breaking strength, maximum elongation, and area reduction between specimens with and without LIPSS, all obtained from the same foil. Additionally, we utilized scanning electron microscopy (SEM) to compare the LIPSS morphology of laser-treated samples before and after mechanical tests.

A study of high-strength and durable cotton fabric joining via laser-induced polymerisation of silica-sol photosensitive resin

Cotton is the most popular fabric used in human clothing and garment, and its joining process is still based on the traditional sewing method. In this study, a new approach to cotton fabric joining via UV-laser induced polymerisation was investigated, which involved preparation of a silane coupling agent (3-Aminopropyl) triethoxysilane (3-Aps) for surface modification of cotton fabric, and formulation and application of a silica-sol photosensitive resin as the filler. The developed resin consists of two other silanes, Silane A174 and KH560 so as to provide chemical bonds with the cellulose of cotton surface and the 3-Aps modified cotton. The results showed that the silica-sol resin not only produced self-polymerisation due to photothermal effect, but also joined with the fiber surfaces by chemical bonding, which enhanced the surface interaction with cotton fibers and obtained excellent mechanical properties. The heat accumulation at joint was detected in real-time using the infrared thermography, which ensured the fast drying and curing of the silica-sol containing resin. With 4 % silica-sol content in resin, the interfacial bonding was optimal for APS-Fabric, and the tensile force of the 2 mm joint reached 300 N exceeding the ultimate breaking strength of the cotton fabric itself. The fabric joint was demonstrated to withstand at least 20 washing cycles without cracking. This new fabric joining technique provides both strong bonding and sufficient flexibility in the joints, resulting in high strength and durable cotton fabric joining, which has a broad application prospect in the field of apparel.

Natural-Wood-Inspired Ultrastrong Anisotropic Hybrid Hydrogels Targeting Artificial Tendons or Ligaments.

Hydrogels are able to mimic the flexibility of biological tissues or skin, but they still cannot achieve satisfactory strength and toughness, greatly limiting their scope of application. Natural wood can offer inspiration for designing high-strength hydrogels attributed to its anisotropic structure. Herein, we propose an integrated strategy for efficient preparation of ultrastrong hydrogels using a salting-assisted prestretching treatment. The as-prepared poly(vinyl alcohol)/cellulose nanofiber hybrid hydrogels show distinct wood-like anisotropy, including oriented molecular fiber bundles and extended grain size, which endows materials with extraordinarily comprehensive mechanical properties of ultimate breaking strength exceeding 40 MPa, strain approaching 250%, and toughness exceeding 60 MJ·m-3, and outstanding tear resistance. Impressively, the breaking strength and toughness of the reswollen preoriented hydrogels approach 10 MPa and 25 MJ·m-3, respectively. In vitro and in vivo tests demonstrate that the reswollen hydrogels do not affect the growth and viability of the cells, nor do they cause the inflammation or rejection of the mouse tissue, implying extremely low biotoxicity and perfect histocompatibility, showcasing bright prospects for application in artificial ligaments or tendons. The strategy provided in this study can be generalized to a variety of biocompatible polymers for the fabrication of high-performance hydrogels with anisotropic structures.

Random corrosion characteristics of high strength steel wire after 18 years of service and the numerical reconstruction method

This work aims at studying the random corrosion characteristics and residual strength of high strength steel wire after 18 years of service. Salt-spray accelerated corrosion test was carried out on the aged specimen, the mass loss characteristic was determined, the corrosion morphology of steel wire was obtained and reconstructed by 3D optical scanning and the corrosion characteristics were quantified by statistical analysis. Comparing with the corrosion behavior of the steel wire without service, it indicated that the corrosion of aged steel wire is much severe, and the damaged zinc coating and the accumulated fatigue damage should be responsible for it. The ultimate breaking strength of the corroded steel wire was then determined by tensile test, and the fracture morphology was characterized by SEM. A numerical reconstruction method of random corroded wire was proposed, which can be used for the residual strength assessment of aged corroded wire, and systematic parametric studies was also carried out.

Mechanical properties of rice husk ash, an environmental pollutant, based composites: A step towards sustainable hybrid composites

ABSTRACT There is a dual perspective regarding agricultural materials. The first one is regarding the removal of certain chemical elements for specific applications, and the second one is regarding the recovery of certain elements to make them more appealing. The most appropriate use of agricultural and industrial waste materials demands the development of knowledge insights as a requirement for setting up of demonstration plants on a pilot basis and large-scale industrial adoption resulting in all associated socio-economic benefits. The Stir casting method is employed to fabricate the Metal Matrix Composites (MMCs) material for the application of various industrial products. In the present paper, Aluminum (Al6061) hybrid composite is fabricated and reinforced with Silicon Carbide (SiC), Alumina (Al2O3), Zirconia (ZrSiO4) and agro-waste material, such as Rice Husk Ash (RHA) particles of various configurations. The amount of reinforcement varies SiC (0–2.5 wt%), Al2O3 (0–1.1 wt%), ZrSiO4 (0–0.5 wt%) and RHA (0–1.4 wt%). The effect of reinforcement SiC, Al2O3, ZrSiO4 and RHA on ultimate tensile strength (σut), yield strength (σyt), elongation, breaking strength (σb) and hardness has been studied. Experimental results revealed that hybrid metal matrix composites are improved for σut and σyt by 45.03% and 82.1%. The elongation and hardness of the composite are also enhanced by 19.43% and 12.72% from the base material.

Investigation on Tensile Properties of Austempered SAE52100 Steel

The tensile test is an important test to determine several mechanical properties in which a sample is subjected to a constant strain rate until failure. Properties that are directly measured in a tensile test are ultimate tensile strength, breaking strength, maximum elongation, and reduction in area. The present research compared the tensile properties between austempered SAE52100 steel and quench-tempered SAE52100 steel under equivalent hardness. The experimental results showed that the ultimate tensile strength and yield strength of quench-tempered specimens was higher than austempered specimens. However, the total elongation and area reduction of quench-tempered specimens was lower than austempered specimens. Transgranular quasi-cleavage fracture was found on the austempered SAE52100 steel specimens. While using the austempering temperature of 288 °C, slight plastic deformation with existence of cleavage facets and ductile risers around the edges was obtained. However, while using the austempering temperature of 427 °C, the presence of tear marks on the cleavage facets surrounded by dimples indicated significant plastic deformation or ductile rupture. The fracture analysis could be correlated with the elongation obtained in tensile tests.

Change in Structure and Mechanical Properties of Grade А0 Aluminum During Implementation of a Combined Method of ECAE–Drawing Deformation

The effect of combined technology of ECAE-drawing on features of ultrafine-grained (UFG) structure formation in aluminum alloy А0 is considered. Deformation by the proposed and existing schemes is conducted at room temperature with the number of passes equal to four. It is shown that ECAE-drawing leads to more significant refinement of the structure of pure aluminum compared with traditional drawing. The grains obtained are equiaxed in shape, and their size lies in the range from 0.7 to 0.8 μm. It is also established that aluminum wire strength increases after four passes by almost a factor of three. Ultimate breaking strength and yield strength increase from 145 to 400 MPa (the absolute increase is 255 MPa) and from 100 to 224 MPa (the absolute increase is 114 MPa) respectively, relative elongation is reduced by 7%, and reduction of area is reduced by 5%. It is found that after deformation by the ECAE-drawing method wire has an increased reserve of ductility compared with the traditional drawing process that makes it possible to accomplish subsequent treatment without intermediate annealing.

Technology for Modifying Aluminum Alloys with Ultrafine Silicon

Results are provided for a study of the structure and mechanical properties of alloy AK12 modified with tabletted ultra-finely dispersed modifier based on silicon carbide, introduced “beneath a metal stream” without additional mixing, and in a rotary device. It is established that the optimum method for introducing modifier is that of “beneath a metal stream.” In this case the ultimate breaking strength increases from 110 to 150 MPa, nominal yield strength from 85 to 94 MPa, and relative elongation from 2.3 to 6.2% (metal pouring temperature into a mold 750 °C). Metallographic examination is used to determine the reduction in macro-grain size in test pigs (ingots) by a factor of four compared with control alloys, absence of porosity, and an increase in ingot density from 2.59 to 2.66 g/cm3. Introduction of ultra-finely dispersed modifier based on silicon carbide increases the number of crystallization centers in a 1 kg ingot to 2·1011 units.

A finite element method of modelling and designing of an ACCC conductor

The ultimate breaking strength of conductors always plays a vital role in the long-term safe operation of transmission lines and it should be carefully considered in the designing of a conductor. While limited literature has been released regarding the strength calculation of ACCC (Aluminum Conductor Composite Core) conductors. In this study, a finite element method based on real conductor samples is proposed to evaluate the strength of the ACCC conductor, and investigate on how diameters (or sectional areas) of the composite core and aluminum strands influence the conductors’ breaking strength, thereby helping engineers design a proper diameter of an ACCC conductor. The finite element analysis shows that increasing the sectional area of the composite core leads to a larger breaking strength than increasing an equal sectional areas of aluminum strands, which is in line with the tensile experimental results. In specific, the relative errors between the simulated breaking strength and the experimental results are as low as less than 3%. Therefore, the finite element method presented in this work, to some extent, fills in the blank of strength calculation for ACCC conductors, and in practical terms, it could serves as guidelines for conductor-design engineers.

High performance hybrid reinforcement of nitrile rubber using short pineapple leaf fiber and carbon black

Rubber composites with very high moduli at low elongation, high elongation at break and high ultimate breaking strength have been developed. The matrix was acrylonitrile butadiene rubber (NBR) and the hybrid (fibrous and particulate) reinforcements were short, fine pineapple leaf fiber (PALF) and carbon black. The amount of PALF was fixed at 10 parts (by weight) per hundred of rubber (phr) while that of carbon black was varied from 0 to 30 phr. Uniaxial NBR composites were prepared. Tensile strength, elongation at break, modulus and tear strength of the hybrid composites were characterized in both longitudinal (parallel to the fiber axis) and transverse (perpendicular to the fiber axis) directions. The addition of carbon black causes the slope of the early part of the stress–strain curve to increase and also extends breaking to greater strains. At carbon black contents of 20 phr and above, the stress–strain relation displays an upturn at high elongations, providing greater ultimate strength. Comparison with the usual carbon black filled rubber shows that the composite behavior at low strains is determined by the PALF, and at high strains by the carbon black. This high performance PALF-carbon black reinforced NBR shows great promise for engineering applications.

Biomechanical evaluation of double-strand (looped) and single-strand polyamide multifilament suture: influence of knot and suture size.

Flexor tendon repair in zone II remains a vexing problem. Repair techniques have been developed to strengthen and optimize the number of core strands crossing a repair. A polyamide looped suture doubles the number of core strands for every needle path. This simplifies repairs, but the knot remains a potential weakness. The purpose of our study was to create a biomechanical model used to evaluate the bulky knot of a looped suture as it may be weaker, resulting in greater deformation. Using machined steel rods to hold our suture constructs, we compared four different knot configurations using looped and non-looped sutures in 3-0 and 4-0 varieties using a four-core strand technique. The constructs were tested under increased cyclic loading recording both forces applied and suture construct lengthening ("clinical gapping") and ultimate breaking strength. During continuous periods of cyclic loading, we measured permanent deformation and ultimate breaking strength. Permanent deformation results when there is no recoverable change after force removal defined as a permanent rod separation (or gapping) of 2mm. Four-strand 3-0 and 4-0 looped sutures failed at 39.9 and 27.1N faring worse than a four-strand non-looped suture which reached a rod separation of 2mm at 60.7 and 41.3N. The ultimate breaking strength demonstrated absolute failure (construct rupture) with the 3-0 looped suture breaking at the knot at 50.3N and the non-looped suture at 61.5N. For the 4-0 suture, these values were 32.4 and 41.76N. Within the constraints of this model, a looped suture fared worse than a non-looped suture especially when comparing 4-0 and 3-0 sutures. However, two-knot 3-0 looped suture constructs did resist the force generally accepted as occurring with early non-resistive tendon motion protocols, while two-knot 4-0 looped suture constructs did not. This paper provides a description of a model to evaluate various suture materials and knot strengths in isolation of the tendon itself. This allowed us to evaluate mechanical differences between looped and non-looped sutures for polyamide, which are commonly used in flexor tendon repair. These differences between sutures may impact choices for a suture type selected for these repairs.

The influence of UV-irradiation on thermal and mechanical properties of chitosan and silk fibroin mixtures

In the present paper the results regarding the influence of UV-irradiation with 254nm wavelength on the thermal and mechanical properties and the intrinsic viscosity of chitosan/silk fibroin mixtures are presented.The mixture of chitosan and silk fibroin in solution and thin films made of chitosan/silk fibroin mixture obtained by solvent evaporation were submitted to the treatment with UV irradiation (wavelength 254nm) for different time intervals. Mechanical properties of thin films made of chitosan/silk fibroin blends before and after UV-irradiation have been investigated by mechanical testing machine and compared with mechanical properties of chitosan films. The changes in such mechanical properties as ultimate breaking strength, percentage of elongation at break and Young Modulus have been investigated.The results have shown, that the mechanical properties of the blends were greatly affected by time of exposure to UV irradiation. Ultimate tensile strength and ultimate percentage of elongation decreased after UV irradiation of the blend. Increasing UV irradiation led to the decrease in Young’s Modulus of the chitosan/silk fibroin blend. Viscosity of chitosan/silk fibroin mixtures decreased after UV-irradiation. Thermal properties of the mixtures have been only slightly altered by UV-irradiation.

Study of the structure and fluidity of alloy of the Al–Si–Mg system with a different calcium content

The effect of calcium in an amount of 0.1–1.0% on aluminum alloy modification with the aim of revealing the optimum composition in order to achieve required properties is studied. New aluminum alloys and their production properties (fluidity and processing capacity), chemical properties (corrosion resistance), and also mechanical properties (ultimate breaking strength, ductility, relative elongation, and hardness), are studied. General structural analysis is performed providing identification of individual components and new calcium compounds in aluminum alloy.

Surface‐Structured Gold‐Nanotube Mats: Fabrication, Characterization, and Application in Surface‐Enhanced Raman Scattering

The fabrication and characterization of nanostructured fibrous gold mats having high specific surface areas is reported. Freestanding porous films of 6-20-μm thickness and density 0.43 ± 0.02 g cm(3) are prepared using e-beam evaporation of gold on an electrospun nanoporous polymer template and subsequent removal of the template polymer in a suitable solvent. Structural characterization using electron microscopy techniques shows a nanofiber diameter in the range of 300-6000 nm, and the size of the nanochannels on the fiber surface is ≈200-350 nm. Such surface structuring is achieved through fast evaporation of organic solvent and phase separation of polymers during the electrospinning process. The wedge thickness varies from a few nanometers to a few tens of nanometers. The freestanding films possess good mechanical integrity and robustness. The calculated Young's modulus based on the slope in the elastic region is ≈114 MPa and gives an ultimate breaking strength of 0.7-0.8 MPa at a percentage elongation of 1.5-2.0%. X-ray diffraction and transmission electron microscopy measurements demonstrate the formation of polycrystalline gold nanostructures. Electrical characterization performed on these gold nanotubes reveals pure metallic behavior. Raman spectroscopic characterization of the fibrous membrane is performed using crystal violet (CV) adsorbed on it. Well-defined spectral peaks are obtainable at concentrations as low as 10(-7) M of CV, which did not give spectral signals at this low concentration on its own.

Novel Polysaccharide‐derived hydrogel prevents perineural adhesions in a rat model of sciatic nerve adhesion

We investigated the effects of a novel carboxymethylcellulose (CMC)-derived hydrogel, in which phosphatidylethanolamine (PE) was introduced into the carboxyl groups of CMC, for preventing perineural adhesion after extensive internal neurolysis of rat sciatic nerve. Sciatic nerves were randomly assigned to one of the following groups: the Control group, operated but no treatment; the HA group, operated and treated with 1% hyaluronan; the CMC-PE(L) group, operated and treated with low-viscosity CMC-PE hydrogel; and the CMC-PE(H) group, operated and treated with high-viscosity CMC-PE hydrogel. Perineural adhesions were evaluated at 6 weeks. Nerves were also subjected to biomechanical testing to assess ultimate breaking strength. Electrophysiological and wet muscle weight measurements were performed. Breaking strengths were significantly lower for the CMC-PE(L) group than for the Control and HA groups. Latency was significantly longer for the Control group than for the CMC-PE(L) group at 20 days. The mean percentage of wet muscle weight to body weight was significantly lower for the Control group than for the CMC-PE(L) group at 6 weeks. Low-viscosity CMC-PE hydrogel appears to prevent perineural adhesions and allow early restoration of nerve function.

Effects of heat treatment on deformation characteristics of medium carbon steel

The effects of heat treatment on bending deformation, tensile strength and hardness of RST 37 medium carbon steels were investigated. Steel rod samples of ø12 mm diameter, 100 mm length, and % weight composition of 0.39 wt % C, 0.70 wt % Mn and 0.80 wt % Si and traces of alloying elements were tested. The samples were austenitized at 1123 K, annealed, normalized, quenched and tempered. Mechanical tests conducted on the sam-ples were bending, hardness, ultimate tensile strength, % elongation, breaking strength, yield strength, and yield ratio. The results showed that annealed, normalized and tempered samples exhibited high springback, while the hardened samples showed relatively low springback. As the tensile strength or yield strength increased, ductili-ty or total elongation decreased. The hardness was found to decrease with increasing springback. Journal of Applied Science and Technology Vol. 13 (1 & 2) 2008: pp. 81-85

ジルコニアを用いた臼歯部のオールセラミックスレストレーション

In spite of its high esthetic and biocompatible properties of the all ceramics restorations, it was not applicable for the clinical usage with molars, especially fixed partial dentures, due to its mechanical weakness. It is reported in the recent studies that zirconia has high bending and ultimate breaking strength, thus is more durable to the fracture in comparison with the other ceramic systems. All ceramics restorations with zirconia copings now can be used for the posteriors fixed bridges.In this report, prosthetic procedures for fabricating all ceramics restorations with zirconia copings on both sides of the mandibular molars are described.

Potential mechanism of action of insulin as an anti-scarring agent

Introduction: Previously we have identified insulin but not the closely related insulin-growth factor 1 (IGF-I) as an inhibitor of the fibrosis-associated fibroblast phenotype, the myofibroblast. Insulin's efficacy was demonstrated in vitro on normal tissue-derived (dermis and normal scar), and pathological (keloid and hypertrophic scar) fibroblasts. In a murine model a single subcutaneous infiltration of low dose insulin significantly reduced the presence of myofibroblasts in the healing wound without reducing its ultimate breaking strength. We have attempted to further dissect insulin's mechanism of action in this respect, an understanding of which will allow us to design more specific pharmaceutical agents to use in anti-scarring therapeutics.

Postnatal growth of broilers in response to in ovo administration of chicken growth hormone

The effect of in ovo administration of chicken growth hormone (cGH) on growth rate and efficiency of gain, organ, and long bone growth of 42-d-old broiler chickens was investigated. Eggs were injected once with 100 microL vehicle (0.03 M NaHCO3, 0.15 M NaCl, pH 8.3) per embryo or vehicle containing 100 ng cGH/100 microL per embryo (n = 630 eggs total) on one of the following Days: 1, 4, or 7 through 18 of embryogenesis. There was no significant difference in hatchability between control and cGH treatment groups on any given injection day. Cumulative feed conversion of all treatment groups was improved relative to their respective control groups (P < 0.05). In ovo administration of cGH on Day 15 or 16 of incubation increased body weights (P < 0.01) of female broilers. On the other hand, body weights of male broilers were significantly increased by treatment on Day 1 (P < 0.04). Breast weights of female broilers from treatment groups Day 15 or 16 were increased (P < 0.01, P < 0.05, respectively). Liver weights of female broilers from treatment groups Day 1 and 15 were increased (P < 0.05, P < 0.01, respectively). In contrast, in ovo administration of cGH on Day 11 of incubation increased liver weights of male broilers (P < 0.03). There was no significant difference between control and treatment groups, in terms of heart or leg weights, or in Warner-Bratzler shear force of Pectoralis profundus muscle. Hydroxyproline concentration and cross-sectional area of female broiler tibias from treatment groups Day 11 or Day 16 were increased (P < 0.05), and ultimate breaking strength (stress) of tibias from the same groups was reduced (P < 0.05). In ovo administration of cGH altered growth and tissue development of broiler chickens in a time by sex dependent fashion.