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PCL/HA静电纺丝纤维涂层对可降解mg/HA复合材料的表面改性:力学性能、腐蚀和生物相容性

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Transactions of Nonferrous metals Society of China 2024年第5期34卷 1470-1486页

作者： m.SHAmSI m.sedighi A.BAGHErI School of mechanical Engineering Iran University of Science and TechnologyTehranIran

采用搅拌铸造和挤压法制备mg/HA复合材料,并在其表面采用静电纺丝法涂覆聚己内酯/羟基磷灰石(PCL/HA)纤维(2.5%和5%HA,质量分数),以提高其耐腐蚀性。力学性能测试结果表明,复合材料的压缩屈服强度从73mPa(纯镁)提高到151mPa,提高了107%... 详细信息

采用搅拌铸造和挤压法制备mg/HA复合材料,并在其表面采用静电纺丝法涂覆聚己内酯/羟基磷灰石(PCL/HA)纤维(2.5%和5%HA,质量分数),以提高其耐腐蚀性。力学性能测试结果表明,复合材料的压缩屈服强度从73mPa(纯镁)提高到151mPa,提高了107%。SEm、EDS和XrD分析表明,HA颗粒分布在多孔涂层中。极化曲线结果表明,涂层试样的耐腐蚀性能均优于未涂覆试样。PCL涂层使样品的腐蚀电流密度降低了两个数量级。通过极化和体外腐蚀试验证明了HA在涂层中的有效性。涂层和随后形成的Ca-P层阻碍了模拟体液与基体的接触和渗透,从而起到保护表面的作用。PCL/2.5%HA涂层样品的腐蚀速率最低,其平均值为0.98mm/a,与未涂层样品相比,在14天内减少了81%。根据3天mTT结果,使用PCL/2.5%HA涂层可使细胞活性从43%提高到121%。综上,涂覆PCL/2.5%HA纤维的mg/HA复合材料在生物可吸收植入物方面具有广阔的应用前景。

关键词：镁基复合材料复合涂层生物可降解羟基磷灰石聚己内酯纤维

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Severe plastic deformation (SPD) of biodegradable magnesium alloys and composites: A review of developments and prospects

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Journal of magnesium and Alloys 2022年第4期10卷 938-955页

作者： m.Kasaeian-Naeini m.sedighi r.Hashemi School of mechanical Engineering Iran University of Science and TechnologyTehranIran

The use of magnesium in orthopedic and cardiovascular applications has been widely attracted by diminishing the risk of abnormal interaction of the implant with the body tissue and eliminating the second surgery to remove it from the ***,the fast degradation rate and generally inhomogeneous corrosion subsequently caused a decline in the mechanical strength of mg during the healing *** researches have been conducted on the influences of various severe plastic deformation(SPD)processes on magnesium bioalloys and *** paper strives to summarize the various SPD techniques used to achieve magnesium with an ultrafine-grained(UFG)***,the effects of various severe plastic deformation methods on magnesium microstructure,mechanical properties,and corrosion behavior have been ***,this review intends to clarify the different potentials of applying SPD processes to the magnesium alloys and composites to augment their usage in biomedical applications.

关键词： magnesium Severe plastic deformation Biodegradable implant mechanical properties Corrosion

Divergence and flutter instability of magneto-thermo-elastic C-BN hetero-nanotubes conveying fluid

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Acta mechanica Sinica 2020年第2期36卷 381-396页

作者： Hamid m.sedighi mechanical Engineering Department Faculty of EngineeringShahid Chamran University of AhvazAhvaz 61357-43337Iran Drilling Center of Excellence and research Center Shahid Chamran University of AhvazAhvaz 61357-43337Iran

On the basis of finite element analysis,an eigenvalue problem is performed to examine the vibrational characteristics of a hetero-nanotube made of carbon(C)and boron nitride(BN)nanotubes in magnetic and thermal *** incorporating the assumption of nonlocal elasticity theory,the size-dependent behavior of the considered structure is also taken into *** obtained results demonstrate that the onset of the divergence and flutter instabilities may be postponed by exploiting a hetero-nanotube rather than a uniform one composed of carbon ***,it is exhibited that,in the presence of fluid flow,the mode shape configuration of nanotubes may be different from those of classical modes and therefore the later one should not be utilized in the dynamic analysis of fluid-conveying ***,it is shown that,as the temperature decreases,the natural frequencies of the system decrease in high temperature conditions and increase for the case of room temperature.

关键词： Hetero-nanotube Fluid-conveying magnetic flow Nonlocal elasticity Thermal environment

应变路径对AA1050铝板力学性能、成形极限曲线及织构演化影响的实验研究

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中南大学学报:英文版 2023年第8期30卷 2472-2484页

作者： A.rOUZBEH S.m.ATIFEH m.sedighi r.HASHEmI School of mechanical Engineering Iran University of Science&TechnologyNarmak ***Iran

实验研究了应变路径变化对AA1050铝合金力学性能、成形性能和成形极限的影响。讨论了以单向、反向和交叉轧制的三种不同方式的应变路径。对比了三种轧制方式在20%和40%轧制比下的晶粒尺寸、硬度、应力-应变曲线和成形极限。结果表明,交... 详细信息

实验研究了应变路径变化对AA1050铝合金力学性能、成形性能和成形极限的影响。讨论了以单向、反向和交叉轧制的三种不同方式的应变路径。对比了三种轧制方式在20%和40%轧制比下的晶粒尺寸、硬度、应力-应变曲线和成形极限。结果表明,交叉轧制试样的晶粒尺寸小于其他方式轧制试样的晶粒尺寸;单向和交叉轧制试样的强度和伸长率均高于反向轧制方式的,单向和交叉轧制试样的硬度等于或大于反向轧制试样的;此外,交叉轧制使试样的各向异性减小,r趋近于1。试样的成形极限在交叉轧制方式下明显提高,在40%轧制比下,交叉轧制的FLC_(0)为0.113,单向轧制的FLC_(0)为0.09,反向轧制的FLC_(0)为0.081。单向和反向轧制的成形极限与加载路径的相关。

关键词：应变路径成形性轧制方向织构演变铝合金板

Straightforward method for Nonlinear Oscillators

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Journal of Donghua University(English Edition) 2023年第1期40卷 105-109页

作者：吕国娟何吉欢何春辉 sedighi Hamid m School of Science Xi’an University of Architecture and TechnologyXi’an 710055China School of mathematics and Information Science Henan Polytechnic UniversityJiaozuo 454003China National Engineering Laboratory for modern Silk College of Textile and ClothingEngineeringSoochow UniversitySuzhou 215021China School of Civil Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Faculty of Engineering Shahid Chamran University of AhvazAhvaz61357-43337Iran

It is challenging to predict the frequency property of a nonlinear vibration system conveniently and ***,an invalid or physically irrelevant result might be obtained by some advanced ***,predicting the frequency lacks an expedient and efficient *** challenge is addressed by developing a straightforward and effective frequency formulation that reliably predicts the frequency-amplitude *** study provides a one-step approach which can fast determine the periodic properties of any conservative oscillators and also provides a reference for other similar studies.

关键词： He's frequency formulation Duffing oscillator nonlinear oscillator

Static and Dynamic Pull-In Instability of Nano-Beams resting on Elastic Foundation Based on the Nonlocal Elasticity Theory

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Chinese Journal of mechanical Engineering 2017年第2期30卷 385-397页

作者： HAmID m sedighi ASHKAN Sheikhanzadeh mechanical Engineering Department Faculty of EngineeringShahid Chamran University of Ahvaz Departmentof mechanical Engineering Najafabad BranchIslamic Azad Univesity

This paper provides the static and dynamic pullin behavior of nano-beams resting on the elastic foundation based on the nonlocal theory which is able to capture the size effects for structures in micron and sub-micron scales. For this purpose, the governing equation of motion and the boundary conditions are driven using a variational approach. This formulation includes the influences of fringing field and intermolecular forces such as Casimir and van der Waals forces. The differential quadrature （DQ） method is employed as a high-order approximation to discretize the governing nonlinear differential equation, yielding more accurate results with a Considerably smaller number of grid points. In addition, a powerful analytical method called parameter expansion method （PEm） is utilized to compute the dynamic solution and frequency-amplitude relationship. It is illustrated that the first two terms in series expansions are sufficient to produce an acceptable solution of the mentioned structure. Finally, the effects of basic parameters on static and dynamic pull-in insta- bility and natural frequency are studied.

关键词： Static and dynamic pull·in voltages Size dependent Nonlocal theory Euler·Bernoulli beam model Differential quadrature method Parameter Expansion method

Strain-rate Dependency of a Unidirectional Filament Wound Composite under Compression

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Computer modeling in Engineering & Sciences 2023年第12期137卷 2149-2161页

作者： Stepan Konev Victor A.Eremeyev Hamid m.sedighi Leonid Igumnov Anatoly Bragov Aleksandr Konstantinov Ayaulym Kuanyshova Ivan Sergeichev Skolkovo Institute of Science and Technologies Center for Materials TechnologiesMoscowRussia National research Lobachevsky State University of Nizhny Novgorod Nizhny NovgorodRussia Dipartimento di Ingegneria Civile Ambientale e Architettura(DICAAR)Universitàdegli Studi di CagliariCagliari(CA)Italy mechanical Engineering Department Faculty of EngineeringShahid Chamran University of AhvazAhvazIran Drilling Center of Excellence and research Center Shahid Chamran University of AhvazAhvazIran

This article presents the results of experimental studies concerning the dynamic deformation and failure of a unidirectional carbon fiber reinforced plastic(T700/LY113)under *** test samples were manufactured through the filament winding of flat *** establish the strain rate dependencies of the strength and elastic modulus of the material,dynamic tests were carried out using a drop tower,the Split Hopkinson Pressure Bar method,and standard static *** samples were loaded both along and perpendicular to the direction of the reinforcing *** applicability of the obtained samples for static and dynamic tests was confirmed through finite elementmodeling and the high-speed imaging of the deformation and failure of samples during *** a result of the conducted experimental studies,static and dynamic stress-strain curves,time dependencies of deformation and the stress and strain rates of the samples during compression were *** on these results,the strain rate dependencies of the strength and elasticity modulus in the strain rate range of 0.001-6001/s are *** is shown that the strain rate significantly affects the strength and deformation characteristics of the unidirectional carbon fiber composites under *** increase in the strain rate by 5 orders of magnitude increased the strength and elastic modulus along the fiber direction by 42%and 50%,*** loading resulted in a strength and elastic modulus increase by 58%and 50%,*** average strength along the fibers at the largest studied strain rate was about *** obtained results can be used to design structural elements made of polymer composite materials operating under dynamic shock loads,as well as to build models of mechanical behavior and failure criteria of such materials,taking into account the strain rate effects.

关键词： High strain rate composites filament winding dynamic strength Split Hopkinson Pressure Bar compression

Effect of stiffeners on crashworthiness of square aluminium columns considering damage evolution

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Journal of Central South University 2013年第3期20卷 599-607页

作者： H.r.Allahbakhsh m.Shariati m.sedighi mechanical Department Damghan BranchIslamic Azad UniversityDamghan 36716-39998Iran mechanical Department Ferdowsi University of MashhadMashhad 91779-48974Iran

Combining the optimization and FEm technology,crashworthiness of aluminum extrusions was studied for an automobile safety *** effects of longitudinal stiffeners on the crushing of stiffened square columns were studied considering the damage *** numerical analysis was carried out by ABAQUS ***,the collapse behavior of aluminum extrusion damage was validated by comparing against solution published in ***,in order to find more efficient and lighter crush absorber and achieving minimum peak crushing force,response surface methodology(rSm) has been applied for optimizing the aluminum extrusion tube.

关键词：铝合金型材损伤演化 ABAQUS软件有限元分析技术方形安全计划数值分析响应面法

DYNAmIC PULL-IN INSTABILITY OF DOUBLE-SIDED ACTUATED NANO-TOrSIONAL SWITCHES

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Acta mechanica Solida Sinica 2015年第1期28卷 91-101页

作者： Hamid m.sedighi Kourosh H.Shirazi Department of mechanical Engineering Shahid Chamran University

A nonlinear frequency-amplitude relation is developed to investigate the vibrational amplitude effect on the dynamic pull-in instability of double-sided-actuated nano-torsional switches. The governing equation of a nano-electro-mechanical system pre-deformed by an electric field contains the quintic nonlinear term. The influences of basic parameters on the pull-in instability and natural frequency are investigated using a powerful analytical approach called the homotopy perturbation method. It is demonstrated that two terms in series expansion are sufficient to produce an acceptable solution. The numerical results obtained have verified the soundness of the asymptotic procedure. The phase portraits of the double-sided nano-torsionalactuator exhibit periodic, homoclinic and heteroclinic orbits.

关键词： homotopy perturbation method frequency-amplitude relationship double-sidedactuated nano-switch dynamic pull-in instability homoclinic orbit heteroclinic orbit