Search results for: tensile loading.

Authors: Farid Saeidi, Serkan Dag

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In this study, fracture analysis of a fibrous composite laminate with variable fiber spacing is carried out using Jk-integral method. The laminate is assumed to be under thermal loading. Jk-integral is formulated by using the constitutive relations of plane orthotropic thermoelasticity. Developed domain independent form of the Jk-integral is then integrated into the general purpose finite element analysis software ANSYS. Numerical results are generated so as to assess the influence of variable fiber spacing on mode I and II stress intensity factors, energy release rate, and T-stress. For verification, some of the results are compared to those obtained using displacement correlation technique (DCT).

Keywords: Jk-integral, variable fiber spacing, thermoelasticity, t-stress, finite element method, fibrous composite.

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Authors: Thevaneyan K. David, John P. Forth

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Integral Abutment Bridges (IAB) are defined as simple or multiple span bridges in which the bridge deck is cast monolithically with the abutment walls. This kind of bridges are becoming very popular due to different aspects such as good response under seismic loading, low initial costs, elimination of bearings, and less maintenance. However the main issue related to the analysis of this type of structures is dealing with soil-structure interaction of the abutment walls and the supporting piles. Various soil constitutive models have been used in studies of soil-structure interaction in this kind of structures by researchers. This paper is an effort to review the implementation of various finite elements model which explicitly incorporates the nonlinear soil and linear structural response considering various soil constitutive models and finite element mesh.

Keywords: Constitutive Models, FEM, Integral AbutmentBridges, Soil-structure Interactions

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Authors: I-Ling Chang, Jer-An Chen

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The elastic properties and fracture of two-dimensional graphene were calculated purely from the atomic bonding (stretching and bending) based on molecular mechanics method. Considering the representative unit cell of graphene under various loading conditions, the deformations of carbon bonds and the variations of the interlayer distance could be realized numerically under the geometry constraints and minimum energy assumption. In elastic region, it was found that graphene was in-plane isotropic. Meanwhile, the in-plane deformation of the representative unit cell is not uniform along armchair direction due to the discrete and non-uniform distributions of the atoms. The fracture of graphene could be predicted using fracture criteria based on the critical bond length, over which the bond would break. It was noticed that the fracture behavior were directional dependent, which was consistent with molecular dynamics simulation results.

Keywords: Energy minimization, fracture, graphene, molecular mechanics.

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Authors: Atjanakul W, Chutima S., Kamnerdthong T.

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Shipping comb is mounted on Head Stack Assembly (HSA) to prevent collision of the heads, maintain the gap between suspensions and protect HSA tips from unintentional contact damaged in the manufacturing process. Failure analysis of shipping comb in hard disk drive production processes is proposed .Field observations were performed to determine the fatal areas on shipping comb and their failure fraction. Root cause failure analysis (RCFA) is applied to specify the failure causes subjected to various loading conditions. For reliability improvement, failure mode and effects analysis (FMEA) procedure to evaluate the risk priority is performed. Consequently, the more suitable information design criterions were obtained.

Keywords: Shipping comb, Hard disk drive, Root cause failureanalysis, Failure mode and effects analysis

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Authors: Levan Nadareishvili, Roland Bakuradze, Barbara Kilosanidze, Nona Topuridze, Liana Sharashidze, Ineza Pavlenishvili

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Some regularities of formation of a new structural state of the thermoplastic polymers - gradually oriented (stretched) state (GOS) are discussed. Transition into GOS is realized by the graded oriented stretching - by action of inhomogeneous mechanical field on the isotropic linear polymers or by zone stretching that is implemented on a standard tensile-testing machine with using a specially designed zone stretching device (ZSD). Both technical approaches (especially zone stretching method) allows to manage the such quantitative parameters of gradually oriented polymers as a range of change in relative elongation/orientation degree, length of this change and profile (linear, hyperbolic, parabolic, logarithmic, etc.). The possibility of obtaining functionally graded materials (FGMs) by graded orientation method is briefly discussed. Uniaxial graded stretching method should be considered as an effective technological solution to create polymer materials with a predetermined gradient of physical properties.

Keywords: Controlled graded stretching, gradually oriented state, linear polymers, zone stretching device.

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Authors: Hyun-Woo Cho, Jae-Heum Moon, Jang-Hwa Lee

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In order to supplement the brittle property of concrete, fibers are added into concrete mixtures. Compared to general concrete, various characteristics such as tensile strength, bending strength, bending toughness, and resistance to crack are superior, and even when cracks occur, improvements on toughness as well as resistance to shock are excellent due to the growth of fracture energy. Increased function of steel fiber reinforced concrete can be differentiated depending on the fiber dispersion, and sand percentage can be an important influence on the fiber dispersion. Therefore, in this research, experiments were planned on sand percentage in order to apprehend the influence of sand percentage on the bending properties and direct tension of SFRC and basic experiments were conducted on bending and direct tension in order to recognize the properties of bending properties and direct tension following the size of the aggregates and sand percentage.

Keywords: Steel Fiber Reinforced Concrete, Bending Toughness, Direct tension.

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Authors: Lenka Bodnárová, Rudolf Hela, Michala Hubertová, Iveta Nováková

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This paper is concerning the issues of behaviour of lightweight expanded clay aggregates concrete exposed to high temperature. Lightweight aggregates from expanded clay are produced by firing of row material up to temperature 1050°C. Lightweight aggregates have suitable properties in terms of volume stability, when exposed to temperatures up to 1050°C, which could indicate their suitability for construction applications with higher risk of fire. The test samples were exposed to heat by using the standard temperature-time curve ISO 834. Negative changes in resulting mechanical properties, such as compressive strength, tensile strength, and flexural strength were evaluated. Also visual evaluation of the specimen was performed. On specimen exposed to excessive heat, an explosive spalling could be observed, due to evaporation of considerable amount of unbounded water from the inner structure of the concrete.

Keywords: Expanded clay aggregate, explosive spalling, high temperature, lightweight concrete, temperature-time curve ISO 834.

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Authors: Rashmi S. H., G. M. Madhu, A. A. Kittur, R. Suresh

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Polymer nanocomposites represent a new class of materials in which nanomaterials act as the reinforcing material in composites, wherein small additions of nanomaterials lead to large enhancements in thermal, optical and mechanical properties. A boost in these properties is due to the large interfacial area per unit volume or weight of the nanoparticles and the interactions between the particle and the polymer. Micro sized particles used as reinforcing agents scatter light, thus reducing light transmittance and optical clarity. Efficient nanoparticle dispersion combined with good polymer–particle interfacial adhesion eliminates scattering and allows the exciting possibility of developing strong yet transparent films, coatings and membranes. This paper aims at synthesising zinc oxide nanoparticles which are reinforced in poly vinyl alcohol (PVA) polymer. The mechanical properties showed that the tensile strength of the PVA nanocomposites increases with the increase in the amount of nanoparticles.

Keywords: Glutaraldehyde, polymer nanocomposites, poly vinyl alcohol, zinc oxide.

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Authors: Kuen-Ming Shu, Cheng-Yu Chen

Abstract:

A vibrating-fork sensor can measure the level height of solids and liquids and operates according to the principle that vibrations created by piezoelectric ceramics are transmitted to the vibrating fork, which produces resonance. When the vibrating fork touches an object, its resonance frequency changes and produces a signal that returns to a controller for immediate adjustment, so as to effectively monitor raw material loading. The design of the vibrating fork in a vibrating-fork material sensor is crucial. In this paper, ANSYS finite element analysis software is used to perform modal analysis on the vibrations of the vibrating fork. In addition, to design and produce a superior vibrating fork, the dimensions and welding shape of the vibrating fork are compared in a simulation performed using the Taguchi method.

Keywords: Vibrating fork, piezoelectric ceramics, sound wave, ANSYS, Taguchi method, modal analysis.

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Authors: J. Gomez-Caturla, L. Quiles-Carrillo, J. Ivorra-Martinez, D. Garcia-Garcia, R. Balart

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The present work reports on the development of wood plastic composites based on biopolypropylene (BioPP) and mango peel flour (MPF) by extrusion and injection molding processes. PP-g-IA and dicumyl peroxide (DCP) have been used as a compatibilizer and as a free radical initiator for reactive extrusion, respectively. Mechanical and morphological properties have been characterized in order to study the compatibility of the blends. The obtained results showed that DCP and PP-g-IA improved the stiffness of BioPP in terms of elastic modulus. Moreover, they positively increased the tensile strength and elongation at break of the blends in comparison with the sample that only had BioPP and MPF on its composition, improving the affinity between both compounds. DCP and PP-g-IA even seem to have certain synergy, which was corroborated through Field Emission Scanning Electron Microscopy (FESEM) analysis. Images showed that the MPF particles had greater adhesion to the polymer matrix when PP-g-IA and DCP were added. This effect was more intense when both elements were added, observing an almost inexistent gap between MPF particles and the BioPP matrix.

Keywords: Biopolypropylene, compatibilization, mango peel flour, wood plastic composite.

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Authors: N. Benachour, A. Hadjoui, M. Benachour, M. Benguediab

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This study reports an empirical investigation of fatigue crack initiation and propagation in 2024 T351 aluminium alloy using constant amplitude loading. In initiation stage, local strain approach at the notch was used and in stable propagation stage NASGRO model was applied. In this investigation, the flat plate of double through crack at hole is used. Based on experimental results (AFGROW Database), effect of stress ratio, R, is highlights on fatigue initiation life (FIL) and fatigue crack growth rate (FCGR). The increasing of dimension of hole characterizing the notch effect decrease the fatigue life.

Keywords: Fatigue crack growth, initiation life, Al-Alloy, stressratio, notch effect

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Authors: Nawapat Detduangchan, Thawien Wittaya

Abstract:

Photo-crosslinked rice starch-based biodegradable films were prepared by casting film-solution on leveled trays and ultra violet (UV) irradiation was applied for 10 minute. The effect of the content (3%, 6% and 9 wt. %)of photosensitiser (sodium benzoate) on mechanical properties, water vapor permeability (WVP) and structural properties of rice starch films were investigated. The tensile strength increased while elongation at break and water resistance properties of rice starch films decreased with addition and increasing content of photosensitiser. The % crystallinity of rice starch films were decreased when the content of photosensitiser increased and UV were applied. The results showed that the carboxylate group band of sodium benzoate was found in the FTIR spectrum of rice starch films and found that incorporation of 6% of photosensitiser into the films showed a higher absorption band of resulted films. This result pointed out the highest interaction between starch molecules was occurred.

Keywords: Biodegradable film, Rice starch, UV treatment, Photosensitiser, Photo-crosslink

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Authors: J. Marzbanrad, A. Yadollahi

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In the present paper, Fatigue life assessment of an anti-roll bar component of a passenger vehicle, is investigated by ANSYS 11 software. A stress analysis is also carried out by the finite element technique for the determination of highly stressed regions on the bar. Anti-roll bar is a suspension element used at the front, rear, or at both ends of a car that reduces body roll by resisting any unequal vertical motion between the pair of wheels to which it is connected. As a first stage, fatigue damage models proposed by some well-known references and the corresponding assumptions are discussed and some enhancements are proposed. Then, fracture analysis of an anti-roll bar of an automobile is carried out. The analysed type of the anti-roll bar is especially important as many cases are reported about the fracture after a 100,000 km of travel fatigue and fracture conditions. This paper demonstrates fatigue life of an anti-roll bar and then evaluated by experimental analytically results from other researcher.

Keywords: Anti-roll bar, Fracture, Fatigue life, Random loading

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Authors: Mohd Yusri Ibrahim

Abstract:

Although it is known that interpersonal skills are essential for personal development, the debate however continues as to how to measure those skills, especially in youths. This study was conducted to develop a measurement model of interpersonal skills by suggesting three construct namely personal, skills and relationship; six function namely self, perception, listening, conversation, emotion and conflict management; and 30 behaviours as indicators. This cross-sectional survey by questionnaires was applied in east side of peninsula of Malaysia for 150 respondents, and analyzed by structural equation modelling (SEM) by AMOS. The suggested constructs, functions and indicators were consider accepted as measurement elements by observing on regression weight for standard loading, average variance extracted (AVE) for convergent validity, square root of AVE for discriminant validity, composite reliability (CR), and at least three fit indexes for model fitness. Finally, a measurement model of interpersonal skill for youth was successfully developed.

Keywords: Interpersonal communication, interpersonal skill, youth.

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Authors: M. Münch, R. Brandt

Abstract:

Martensitic steels with an ultimate tensile strength beyond 2000 MPa are applied in the powertrain of vehicles due to their excellent fatigue strength and high creep resistance. However, the creep controlling mechanism in martensitic steels at ambient temperatures up to 423 K is not evident. The purpose of this study is to review the low temperature creep (LTC) behavior of martensitic steels at temperatures from 363 K to 523 K. Thus, the validity of a logarithmic creep law is reviewed and the stress and temperature dependence of the creep parameters α and β are revealed. Furthermore, creep tests are carried out, which include stepped changes in temperature or stress, respectively. On one hand, the change of the creep rate due to a temperature step provides information on the magnitude of the activation energy of the LTC controlling mechanism and on the other hand, the stress step approach provides information on the magnitude of the activation volume. The magnitude, the temperature dependency, and the stress dependency of both material specific activation parameters may deliver a significant contribution to the disclosure of the nature of the LTC rate controlling mechanism.

Keywords: Activation parameters, creep mechanisms, high strength steels, low temperature creep.

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Authors: Kooshyar Passbakhsh, Maryam Yazdi

Abstract:

Geosynthetics have proved to be suitable for reinforced soil retaining walls. Based on the increasing uses of geosynthetic reinforced soil systems in the regions, which bear frequent earthquakes, the study of dynamic behavior of structures seems necessary. Determining the reinforcement forces is; therefore, one of the most important and main points of discussions in designing retaining walls, by which we prevent from conservative planning. Thus, this paper intended to investigate the effects of such parameters as wall height, acceleration type, vertical spacing of reinforcement, type of reinforcement and soil type on forces and deformation through numerical modeling of the geosynthetic reinforced soil retaining walls (GRSRW) under dynamic loading with finite difference method by using FLAC. The findings indicate rather positive results with each parameter.

Keywords: Geosynthetic Reinforced Soil Retaining Walls (GRSRW), dynamic analysis, Geosynthetic forces, Flac

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Authors: A.R.Nezamabadi, M.Mansouri Gavari, S.Mansouri, M.Mansouri Gavari

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This article considers the positional buckling of composite thick plates under thermal loading . For this purpose , the complex finite strip method is used . In analysis of complex finite strip, harmonic complex function in longitudinal direction , cubic functions in transversal direction and parabola distribution of transverse shear strain in thickness of thick plate based on higherorder shear deformation theory are used . In given examples , the effect of angles of stratification , number of layers , dimensions ratio and length – to – thick ratio across critical temperature are considered.

Keywords: Thermal buckling , Thick plate , Complex finite strip , Higher – order shear deformation theory.

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Authors: N. Zhang, J. S. Kuang, S. Mogili

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To investigate seismic performance of beam-column knee joints, four full-scale reinforced concrete beam-column knee joints, which were fabricated to simulate those in as-built RC frame buildings designed to ACI 318-14 and ACI-ASCE 352R-02, were tested under reversed cyclic loading. In the experimental programme, particular emphasis was given to the effect of horizontal reinforcement (in format of inverted U-shape bars) on the shear strength and ductility capacity of knee joints. Test results are compared with those predicted by four seismic design codes, including ACI 318-14, EC8, NZS3101 and GB50010. It is seen that the current design codes of practice cannot accurately predict the shear strength of seismically designed knee joints.

Keywords: Large-scale tests, RC beam-column knee joints, seismic performance, shear strength.

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Authors: Gayadhar Panda, P. K. Rautraya

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Damping of inter-area electromechanical oscillations is one of the major challenges to the electric power system operators. This paper presents Gravitational Search Algorithm (GSA) for tuning Static Synchronous Series Compensator (SSSC) based damping controller to improve power system oscillation stability. In the proposed algorithm, the searcher agents are a collection of masses which interact with each other based on the Newtonian gravity and the laws of motion. The effectiveness of the scheme in damping power system oscillations during system faults at different loading conditions is demonstrated through time-domain simulation.

Keywords: FACTS, Damping controller design, Gravitational search algorithm (GSA), Power system oscillations, Single-machine infinite Bus power system, SSSC.

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Authors: Fouzieh Rouzmehr, Mehdi Mousavi

Abstract:

Hot mix asphalt concrete is a viscoelastic material, and its stress-strain relationship depends on the loading duration and the strain rate. To investigate the effect of elastic and viscoelastic modeling under traffic load, asphalt concrete pavement is modeled with both elastic and viscoelastic properties and the pavement performance is predicted. The differences of these two models are investigated on fatigue cracking and rutting problem which are the two main design parameters in flexible pavement design. Although the differences in rutting problem between two models were negligible, in fatigue cracking, the viscoelastic model results were more accurate. Results indicate that modeling the flexible pavement with elastic material is efficient enough and gives the acceptable results.

Keywords: Flexible pavement, asphalt, FEM modeling, viscoelastic, elastic, ANSYS.

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Authors: V. Andronie, M. Pârvu, V. Simion, I. Andronie

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The aim of this study was to trace the effects of growth environment on the behaviour of fattening pigs in the farm and outside it. Behavioral manifestations of pigs reared in pens with enriched environment (A lot, n: 22) were different from those of pigs reared in pens with arid environment (B lot, n: 17) in shelter and when the movement to be loaded. Pigs of B lot spent more time on the move (31%) compared to group A pigs (13%), and manifested more aggressive behavior when they were loaded. Salivary cortisol levels also showed high values for pigs in B lot after being removed from their growth environment, as compared to its concentration for A lot pigs. The enriched environment for pigs may determine different responses of behavior. Pigs raised in arid environment, were easier to loaded than pigs reared in enriched environment, but they responded to mixing and loading stress, through increases in cortisol concentrations and impaired behavioral manifestations.

Keywords: environment shelter, pig, behavior

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Authors: Tseng, Wei-Bin., Lou, Jie-Chung, Han, Jia-Yun

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SUVA (equivalent to UV₂₅₄/DOC) value in raw water is a precursor for the formation of trihalomethane during chlorination at a water treatment plant. This study collected rapidly filtered water from an advanced water treatment plant for use in experiments on raw water. The removal rate of treating the trihalomethanes formation potential (THMFP) was conducted by using a biological activated carbon. The hydraulic retention time and SUVA loading were major factors in biological degradation tests. The results showed that biological powder-activated carbon (BPAC) lowered the average concentration of UV₂₅₄ and value of SUVA in raw water. A removal efficiency of THMFP was present in the treatment of the three primary organic carbon items. These results highlighted the importance of the BPAC had an excellent treatment efficiency on THMFP.

Keywords: Water treatment, BPAC, THMFP, SUVA, correlation analysis.

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Authors: A. A. Salisu, M. Y. Yakasai, K. M. Aujara

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Sisal leaves were subjected to enzymatic retting method to extract the sisal fibre. A portion of the fibre was pretreated with alkali (NaOH), and further treated with benzoyl chloride and silane treatment reagents. Both the treated and untreated Sisal fibre composites were used to fabricate the composite by hand lay-up technique using unsaturated polyester resin. Tensile, flexural, water absorption, density, thickness swelling and chemical resistant tests were conducted and evaluated on the composites. Results obtained for all the parameters showed an increase in the treated fibre compared to untreated fibre. FT-IR spectra results ascertained the inclusion of benzoyl and silane groups on the fibre surface. Scanning electron microscopy (SEM) result obtained showed variation in the morphology of the treated and untreated fibre. Chemical modification was found to improve adhesion of the fibre to the matrix, as well as physico-mechanical properties of the composites.

Keywords: Chemical resistance, density test, Sisal fibre, polymer matrix, thickness swelling.

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Authors: M. Shannag, A. Charif, S. Naser, F. Faisal, A. Karim

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Structural lightweight concrete is used primarily to reduce the dead-load weight in concrete members such as floors in high-rise buildings and bridge decks. With given materials, it is generally desired to have the highest possible strength/unit weight ratio with the lowest cost of concrete. The work presented herein is part of an ongoing research project that investigates the properties of concrete mixes containing locally available Scoria lightweight aggregates and mineral admixtures. Properties considered included: workability, unit weight, compressive strength, and splitting tensile strength. Test results indicated that developing structural lightweight concretes (SLWC) using locally available Scoria lightweight aggregates and specific blends of silica fume and fly ash seems to be feasible. The stress-strain diagrams plotted for the structural LWC mixes developed in this investigation were comparable to a typical stress-strain diagram for normal weight concrete with relatively larger strain capacity at failure in case of LWC.

Keywords: Lightweight Concrete, Scoria, Stress, Strain, Silica fume, Fly Ash.

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Authors: Johana Jaramillo, Robin Kalfat, Dmitriy A. Dikin

Abstract:

The cement production process is one of the major sources of carbon dioxide (CO2), a potent greenhouse gas. Indeed, as a result of its cement manufacturing process, concrete contributes approximately 8% of global greenhouse gas emissions. In addition to environmental concerns, concrete also has a low tensile and ductility strength, which can lead to cracks. Graphene Nanoplatelets (GNPs) have proven to be an eco-friendly solution for improving the mechanical and durability properties of concrete. The current research investigates the effects of preparing concrete enhanced with GNPs by using different wet dispersions techniques and mixing methods on its mechanical properties. Concrete specimens were prepared with 0.00 wt%, 0.10 wt%, 0.20 wt%, 0.30 wt% and wt% GNPs. Compressive and flexural strength of concrete at age 7 days were determined. The results showed that the maximum improvement in mechanical properties was observed when GNPs content was 0.20 wt%. The compressive and flexural strength were improved by up to 17.5% and 8.6%, respectively. When GNP dispersions were prepared by the combination of a drill and an ultrasonic probe, mechanical properties experienced maximum improvement.

Keywords: Concrete, dispersion techniques, graphene nanoplatelets, mechanical properties, mixing methods.

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Authors: Harcharan Singh Ranu

Abstract:

Intradiscal and intervertebral pressure transducers were developed. They were used to map the pressures in the nucleus and within the annulus of the human spinal segments. Their stressrelaxation were recorded over a period of time for nucleus pressure, applied load, and peripherial strain against time. The results show that for normal discs, pressures in the nucleus are viscoelastic in nature with the applied compressive load. Mechanical strains which develop around the periphery of the vertebral body are also viscoelastic with the applied compressive load. Applied compressive load against time also shows viscoelastic behavior. However, annulus does not respond viscoelastically with the applied load. It showed a linear response to compressive loading.

Keywords: Intradiscal pressure transducer (IDPT), intervertebral pressure transducer (IVPT), mechanical strains of vertebral bone, viscoelasticity of human spinal disc.

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Authors: P. Vosynek, T. Návrat, M. Peč, J. Pořízka, P. Diviš

Abstract:

Bone properties and response behavior after static or dynamic activation (loading) are still interesting topics in many fields of the science especially in the biomechanical problems such as bone loss of astronauts in space, osteoporosis, bone remodeling after fracture or remodeling after surgery (endoprosthesis and implants) and in osteointegration. This contribution deals with the relation between physiological, demineralized and deproteinized state of the turkey long bone – tibia. Three methods for comparison were used: 1) densitometry, 2) three point bending and 3) frequency analysis. The main goal of this work was to describe the decrease of the protein (collagen) or mineral of the bone with relation to the fracture in three point bending. The comparison is linked to the problem of different bone mechanical behavior in physiological and osteoporotic state.

Keywords: Bone properties, long bone, osteoporosis, response behavior.

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Authors: Ziad. Sh. Al Sarraf

Abstract:

Ultrasonic metal welding has been the subject of ongoing research and development, most recently concentrating on metal joining in miniature devices, for example to allow solder-free wire bonding. As well as at the small scale, there are also opportunities to research the joining of thicker sheet metals and to widen the range of similar and dissimilar materials that can be successfully joined using this technology. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal spot welding device. The ultrasonic metal spot welding horn is modelled using finite element analysis (FEA) and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered effectively to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. The results show how the weld strength is particularly sensitive to the combination of clamping force and ultrasonic vibration amplitude of the welding tip, but there are optimal combinations of these and also limits that must be clearly identified.

Keywords: Ultrasonic welding, vibration amplitude, welding force, weld strength.

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Authors: Mostafa Raki, Mahdi Hamzehei

Abstract:

Equilibrium and stability equations of a thin rectangular plate with length a, width b, and thickness h(x)=C1x+C2, made of functionally graded materials under thermal loads are derived based on the first order shear deformation theory. It is assumed that the material properties vary as a power form of thickness coordinate variable z. The derived equilibrium and buckling equations are then solved analytically for a plate with simply supported boundary conditions. One type of thermal loading, uniform temperature rise and gradient through the thickness are considered, and the buckling temperatures are derived. The influences of the plate aspect ratio, the relative thickness, the gradient index and the transverse shear on buckling temperature difference are all discussed.

Keywords: Stability of plate, thermal buckling, rectangularplate, functionally graded material, first order shear deformationtheory.

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Authors: Sophio Kobauri, Vladimir P. Torchilin, David Tugushi, Ramaz Katsarava

Abstract:

Nanotherapy is an actual newest mode of treatment numerous diseases using nanoparticles (NPs) loading with different pharmaceuticals. NPs of biodegradable polymeric micelles (PMs) are gaining increased attention for their numerous and attractive abilities to be used in a variety of applications in the various fields of medicine. The present paper deals with the synthesis of a class of biodegradable micelle-forming polymers, namely ABA triblock-copolymer in which A-blocks represent amino-poly(ethylene glycol) (H₂N-PEG) and B-block is biodegradable amino acid-based poly(ester amide) constituted of α-amino acid – L-phenylalanine. The obtained copolymer formed micelles of 70±4 nm size at 10 mg/mL concentration.

Keywords: Amino acids, biodegradable poly(ester amide), amphiphilic triblock-copolymer, micelles.

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