Nonlinear dynamic characteristics and optimal control of a giant magnetostrictive film-shaped memory alloy composite plate subjected to in-plane stochastic excitation

The nonlinear dynamic characteristics and optimal control of a giant magnetostrictive film （GMF）-shaped memory alloy （SMA） composite plate subjected to in-plane stochastic excitation are studied. GMF is prepared based on an SMA plate, and combined into a GMF-SMA composite plate. The Van der Pol item is improved to explain the hysteretic phenomena of GMF and SMA, and the nonlinear dynamics model of a GMF-SMA composite cantilever plate subjected to in-plane stochastic excitation is developed. The stochastic stability of the system is analyzed, and the steady-state probability density function of the dynamic response of the system is obtained. The condition of stochastic Hopf bifurcation is discussed, the reliability function of the system is provided, and then the probability density of the first-passage time is given. Finally, the stochastic optimal control strategy is proposed by the stochastic dynamic programming method. Numerical simulation shows that the stability of the trivial solution varies with bifurcation parameters, and stochastic Hopf bifurcation appears in the process; the system＇s reliability is improved through stochastic optimal control, and the first- passage time is delayed. A GMF-SMA composite plate combines the advantages of GMF and SMA, and can reduce vibration through passive control and active control effectively. The results are helpful for the engineering applications of GMF-SMA composite plates.

STUDY ON THE RESPONSE TO LOW-VELOCITY IMPACT OF A COMPOSITE PLATE IMPROVED BY SHAPE MEMORY ALLOY

Improvement from the pseudo-elastic effect of shape memory alloy （SMA） on the low-velocity impact （LVI） resistance of a composite plate is investigated by the finite element method （FEM）. The stiffness matrix of the dynamic finite element equation is established step by step and the martensite fraction is obtained at each time step. The direct Newmark integration method is employed in solving the dynamic finite element equation, while the impact contact force is determined using the modified Hertz＇s law. It is found that SMA can effectively improve the performance of a composite structure subjected to low-velocity impact. Numerical results show that the deflection of a SMA-hybrid composite plate has been reduced approximately by thirty percent when the volume fraction of the embedded SMA reaches 0.3.

Electrochemical behavior of Cu-Zn-Al shape memory alloy after surface modification by electroless plated Ni-P

The electrochemical behavior of Cu-Zn-Al shape memory alloy (SMA) with andwithout electroless plated Ni-P was investigated by electrochemical methods, in artificial Tyrode'ssolution. The results showed that Cu-Zn-Al SMA engendered dezincification corrosion in Tyrode'ssolution. The anodic active current densities as well as electrochemical dissolution sensitivity ofthe electroless plated Ni-P Cu-Zn-Al SMA increased with NaCl concentration rising, pH of solutiondecreasing and environmental temperature uprising. X-ray diffraction analysis indicated that aftersurface modification by electroless plated Ni-P, an amorphous plated film formed on the surface ofCu-Zn-Al SMA. This film can effectively isolate matrix metal from corrosion media and significantlyimprove the electrochemical property of Cu-Zn-Al SMA in artificial Tyrode's solution.

LOW VELOCITY RESPONSE CHARACTERISTICS OF COMPOSITE PLATE WITH EMBEDDED SHAPE MEMORY ALLOY

This paper analyzes the characteristics of utilizing shape memory e?ect (SME) of shape memory alloy (SMA) in improving the low velocity impact resistance performance of com- posite plate by using ?nite element method. The constitutive relation for SMA hybrid composite plates is presented. The analytic model of ?nite element for SMA composite plate subjected to low velocity impact is established. The modi?ed Hertz’s contact law is used to determine the impact contact force. The computing procedures for solving the ?nite element equation using Newmark direct integration method are given. The numerical modelling results show that the SMA can e?ectively improve the low velocity impact resistance performance of composite plate.

Thermo-mechanical Behaviors of Functionally Graded Shape Memory Alloy Timoshenko Composite Beams

This paper focuses on the thermo-mechanical behaviors of functionally graded(FG)shape memory alloy(SMA)composite beams based on Timoshenko beam theory.The volume fraction of SMA fiber is graded in the thickness of beam according to a power-law function and the equivalent parameters are formulated.The governing differential equations,which can be solved by direct integration,are established by employing the composite laminated plate theory.The influences of FG parameter,ambient temperature and SMA fiber laying angle on the thermo-mechanical behaviors are numerically simulated and discussed under different boundary conditions.Results indicate that the neutral plane does not coincide with the middle plane of the composite beam and the distribution of martensite is asymmetric along the thickness.Both the increments of the functionally graded parameter and ambient temperature make the composite beam become stiffer.However,the influence of the SMA fiber laying angle can be negligent.This work can provide the theoretical basis for the design and application of FG SMA structures.

Martensitic transformation and shape memory effect in ausaged Fe-Ni-Si-based alloys

It is well known that the morphologies of the α’ martensite formed from the γ phase in ferrous alloys are classified into five types of lath, butterfly, （225）A type plate,lenticular and thin-plate. Among those α’ martensites, only the thin-plate martensite,which is characterized by containing a high density of transformation twins, has a potential of exhibiting a perfect shape memory （SM） effect.Recently the present authors found in Fe-Ni-Si alloys that the thin-plate martensite is formed by the introduction of fine and coherent γ’-（Ni,Fe）3Si particles with a L12 ordered structure in the austenite matrix due to ausaging. In the present study, the SM properties of the ausaged Fe-Ni-Si alloys with the thin-plate martensite are investigated by a conventional bending-test. The effects of the addition of Co to the Fe-Ni-Si alloys on the martensitic transformation and the SM properties are also investigated. It is shown that while the ausaged Fe-Ni-Si ternary alloys exhibit an imperfect SM effect due to reverse transformation from stress-induced thin-plate martensite to austenite, the SM properties are improved by the addition of Co. An almost perfect SM effect is confirmed in the Fe-Ni-Si-Co alloys by heating to 1 100 ℃ after deformation at -196 ℃.

带孔形状记忆合金薄板弹热性能的实验和理论研究

NiTi形状记忆合金因其优异的弹热效应在新兴固态制冷领域具备广阔的应用前景.然而,该类合金较高的相变临界应力使得其弹热效应需要很高的机械载荷来驱动,对固态制冷器件的小型化和大规模应用带来了挑战.文章通过在NiTi形状记忆合金薄板上引入孔洞,揭示了孔洞体积分数、分布形式对薄板弹热性能的影响.结果表明,孔洞造成的应力集中效应能够在显著降低薄板相变驱动力的同时,有效增加薄板的整体制冷温度和吸热量.薄板在变形过程中的整体力-位移响应和温度演化强烈依赖于孔洞体积分数,孔洞分布形式仅仅影响薄板的局部应力-应变-温度场,而对整体的热-力响应影响较小.进一步地,基于应力对数客观率,在不可逆热力学框架下建立了形状记忆合金有限变形热-力耦合本构模型,并完成了模型的有限元移植.通过与实验结果的对比发现,提出的本构模型能够很好地预测孔洞对NiTi形状记忆合金薄板变形行为和弹热性能的影响,从而为该类合金带孔薄板的设计提供理论工具.

钢横梁SMA蜂窝结构加劲肋面外疲劳性能研究

针对某公路钢桁架桥工字型横梁腹板加劲肋下方出现纵向开裂问题,基于形状记忆合金(SMA)、蜂窝结构和波折腹板特性给出6种加劲肋方案:(1)横梁为原桥直腹板工字钢形状,有腹板间隙;(2)栓接钢板加固;(3)加劲肋为蜂窝结构,横梁为工字钢直板形状;(4)加劲肋为蜂窝结构,腹板为正弦波纹形状;(5)加劲肋为蜂窝结构,腹板为折线形状;(6)加劲肋下部抵住下翼缘板,不焊接。通过三维有限元数值模拟对不同加劲肋结构形式、有无SMA的蜂窝结构加劲肋腹板面外变形、疲劳应力幅和扭转角进行了比较研究。结果表明:腹板间隙处出现较大应力集中与变形扭转;栓接钢板加固、蜂窝结构加劲肋直腹板的抗面外变形疲劳效应效果显著,应力幅与位移都减少80%以上,蜂窝结构加劲肋直腹板相比于栓接钢板加固在提升抗扭转效应基础上钢材用量节约74.07%;蜂窝结构加劲肋折线腹板形式和加劲肋抵住下翼缘板方案不能有效加强抗扭刚度;使用SMA材料更有利于减少面外变形疲劳效应,最大应力幅减少可达77.86%,最大横向位移减少达到33.33%。综上所述,蜂窝结构加劲肋以更少的成本来增强横梁腹板抗面外变形与抗扭刚度。

形状记忆合金对蒸汽发生器一次侧高水位密封组件结构及性能的优化

为替代蒸汽发生器一次侧高水位堵板装拆人工作业,利用形状记忆合金的超弹性,通过在密封组件中预埋形状记忆合金,研制了一种新型密封组件,为在核电高辐射区域应用机器人实施关键设备检修——高水位堵板装拆作业奠定了基础。与传统密封组件相比,新型蒸汽发生器高水位密封组件的结构及性能得到极大优化:省去了干密封—自密封—湿密封3道充气环密封,结构更紧凑轻便,堵板装拆机器人执行末端负载大大减轻(新型密封组件小于5 kg);预埋的形状记忆合金圈采用三道同心圆分布和二次硫化工艺,解决了金属/非金属硫化成型变形问题,回弹性好,从而满足密封组件可折叠进入,同时又可以在仅有中板支撑时稳定、准确地落座在主管道法兰环座上。

胸腔镜下镍钛形状记忆合金接骨板内固定对多发性肋骨骨折患者围手术期指标及肺通气功能的影响

目的:探讨胸腔镜下镍钛形状记忆合金接骨板内固定对多发性肋骨骨折患者围手术期指标及肺通气功能的影响。方法:选取2022年1月—2024年1月枣庄市峄城区人民医院收治的64例多发性肋骨骨折患者作为研究对象,随机分为研究组和对照组,各32例。研究组采取胸腔镜下镍钛形状记忆合金接骨板内固定治疗,对照组采取传统开胸手术内固定治疗,比较两组围手术期指标及肺通气功能。结果:研究组手术时间、术后引流时间和住院时间均短于对照组,研究组术中出血量少于对照组,差异均有统计学意义(P<0.05)。术后第1、3、7天,研究组肺活量、用力肺活量和第1秒用力呼气容积均高于对照组,差异均有统计学意义(P<0.05)。结论:胸腔镜下镍钛形状记忆合金接骨板内固定治疗多发性肋骨骨折,能有效改善患者围手术期指标,提高肺通气功能。

镍钛形状记忆合金骨植入物中环氧乙烷残留量测定方法

目的:建立适合医疗器械产品镍钛形状记忆合金弹力聚合器环氧乙烷残留量测定的顶空气相色谱法。方法:采用气相色谱法-氢火焰离子化检测器进行检测,色谱柱为HP-INNOWax,柱温80℃保持15 min,进样口温度200℃,检测器温度250℃,氢气流量35 mL/min,空气流量350 mL/min,平衡时间40 min。结果:环氧乙烷在1~10μg/mL线性良好,方法检出限0.01 mg/L,精密度RSD=0.01%,回收率在86.6%~96.6%。为保证结果的准确性,样品应立刻测定,剪样面积应尽可能小。结论:该方法操作简单,检出限低,可以用于镍钛形状记忆合金骨植入物中环氧乙烷残留量的快速测定。

腰椎椎体间镍钛记忆合金支架的生物力学分析

目的测试镍钛记忆合金支架的力学性能及用于腰椎间融合术的体外生物力学性能。方法通过力学测试机测试支架的力学性能,并在新鲜腰椎标本上模拟腰椎间融合术,对比分析镍钛记忆合金支架及其配套的骨粒-可吸收骨水泥混凝物浇注植骨方法、传统盒状融合器用于腰椎间融合术的生物力学性能。结果镍钛记忆合金支架最大抗压强度为(12964±962)N,记忆特性有效范围内最大形变为(4.68±0.03)mm,形状恢复率为99.86%。相比于正常腰椎模型,单独使用镍钛记忆合金支架植入模拟腰椎间融合术后手术节段稳定性在前屈、后伸、侧屈、旋转方向上均有增加,与采用传统盒状融合器相当(P>0.05)。而在复合使用配套设计的自体骨粒-可吸收骨水泥混凝物植骨后,手术节段活动度进一步降低(P<0.05),节段稳定性与附加椎弓根螺钉内固定组相当(P>0.05)。镍钛记忆合金支架植入后的抗拔出强度弱于传统盒状融合器(P<0.05),在配合使用自体骨粒-可吸收骨水泥混凝物植骨时的抗拔出强度显著强于传统盒状融合器(P<0.05)。结论本研究的镍钛记忆合金支架同时配套设计了相匹配的骨粒-骨水泥混凝物植骨方式,为腰椎间融合术的进一步优化发展提供了新思路。镍钛记忆合金支架具有良好的支撑及形变性能,用于腰椎间融合术时与传统盒状融合器具有生物力学等效性,在复合应用骨粒-可吸收骨水泥混凝物浇注植骨后能进一步提升稳定性和抗拔出强度。

形状记忆合金混杂复合材料层合板变刚度调控机制

形状记忆合金混杂复合材料(SMAHC)是一种能够主动变化刚度的智能复合材料。为了研究形状记忆合金(SMA)对SMAHC层合板刚度调控的影响,对分布式、模块化地植入SMA的层合板进行三点压弯实验。以SMA数量、单层中SMA排布位置与SMA预应变作为3个独立变量进行正交实验设计,测试了不同试样在不同温度下的刚度值,以研究如何有效地实现刚度调控。采用等效热膨胀法建立SMAHC层合板的有限元模型与实验结果进行对比,总结了SMAHC层合板的变刚度调控机制。分析结果表明,SMA非对称排布的层合板比SMA对称排布的层合板平均刚度提升16.67%;植入8段SMA的层合板比植入4段SMA的层合板平均刚度提升15.26%;通过调整SMA的温度,可以精准地实现SMAHC层合板的刚度调控;模块化、分布式的植入方式能够改变SMAHC层合板整体的应力分布,提升层合板刚度调控精度、降低SMA纤维用量,而且能保证个别SMA失效后层合板整体仍然有一定的变刚度能力。

镍钛形状记忆合金骨植入物镍离子释放的体外测试方法

目的镍钛形状记忆合金骨植入物临床使用过程中存在镍离子析出的风险,植入物镍离子释放在体内很难直接测试,为此本文建立一种镍钛形状记忆合金骨植入物镍离子释放的体外测试方法。方法选用磷酸盐缓冲盐溶液(phosphate buffer salt solution,PBS)作为测试液,用于植入物镍离子的浸提,将植入物置于带盖容器中,容器中装有PBS,将容器静置在温度稳定控制的恒温培养箱内(37±1)℃下,静置相应设置的时间点,每个时间点设1组空白试验和3个相同平行试样进行镍释放量测定,分别用石墨炉原子吸收光谱仪(atomic absorption spectrometer,AAS)和电感耦合等离子体质谱仪(inductively coupled plasma mass spectrometry,ICP-MS)设备测试溶液中镍离子浓度。结果随时间推移从器械中释放出来的镍离子浓度整体呈下降趋势,镍离子释放时点为4周时,释放周期结束,AAS测得镍离子释放量平均值为0.37×10^(-3)μg/(cm^(2)·d),累计释放量平均值为10.22×10^(-3)μg/cm^(2)。ICP-MS测得镍离子释放量平均值为0.29×10^(-3)μg/(cm^(2)·d),累计释放量平均值为7.9×10^(-3)μg/cm^(2)。AAS和ICP-MS两种测试方法测试结果差异性不大,结果数据的走势相同说明试验可重复性高。结论此方法可为镍钛形状记忆合金骨植入物的风险评估提供依据,确保植入物在临床使用过程中镍离子的析出不会对人体造成伤害,保证其临床使用的安全性。

A Novel Implementation of a Flexible Robotic Fin Actuated by Shape Memory Alloy

In this paper, study of a novel flexible robotic-fin actuated by Shape Memory Alloy （SMA） is presented. The developed robotic fin is capable of implementing various 3-Dimensional （3D） motions, which plays an important role in robot propulsion and maneuverability. Firstly, the morphological and mechanics parameters of a real pectoral fin from a carp are investigated. Secondly, a detailed design of the flexible pectoral fin driven by SMA is presented according to the previous morphological and mechanics analyses. Thirdly, a simplified theoretical model on the SMA fin plate is derived. The thermodynamics of the SMA plate and the relationship between curvature and phase transformation are analyzed. Finally, several simulations and model experiments are conducted according to the previous analyses. The results of the experiments are useful for the control of the robotic fin. The experimental results reveal that the SMA actuated fin ray has a good actuating performance.

NiTi合金种植体仿生生长磷灰石涂层及其生物学研究

为赋予NiTi形状记忆合金表面具有生物活性,并探讨类骨磷灰石涂层NiTi作为人工骨修复替代材料的可行性。本研究通过酸碱处理活化NiTi合金,采用仿生方法制备羟基磷灰石涂层,在中国白兔股骨中植入,以无涂层NiTi合金为对照,在植入后15周和26周分别进行组织病理学和超微组织学测试。结果表明仿生生长磷灰石的成分和结构近似于自然骨中的矿物质,晶粒为纳米尺度,是含碳酸根及钙离子缺陷的类骨磷灰石。NiTi/HA植入兔股骨可刺激成骨细胞活跃、增殖,15周后形成完全骨接触界面,且结合状态良好无裂隙。同期NiTi植入体与骨组织间有未吸收的纤维组织,界面结合较差有裂隙。植入26周后,两种种植体与皮质骨均为骨接触。但在髓腔界面,NiTi/HA周围干细胞成骨过程基本完成,新骨紧密包裹种植体;而NiTi表面新骨层残破不全,出现裂隙。说明类骨磷灰石涂层NiTi合金是生物活性材料,有较强的成骨能力,与骨组织间为化学键合。

形状记忆环抱接骨板治疗肋骨骨折临床疗效观察

目的探讨应用形状记忆环抱接骨板手术内固定肋骨骨折的疗效。方法 2009年7月至2012年12月收治215例肋骨骨折患者,104例采用胸带外固定(外固定组),111例采用镍钛合金形状记忆环抱接骨板内固定治疗(内固定组),比较2组患者的疗效。结果 215例患者均治愈出院。内固定组患者痛疼的缓解、动脉血氧分压的改善、胸廓畸形的纠正、肺不张及肺部感染发生率明显较外固定组好,2组比较差异有统计学意义(P<0.05)。结论形状记忆环抱接骨板内固定治疗肋骨骨折具有创伤小、固定可靠、并发症少、疼痛缓解迅速等优点,是临床治疗肋骨骨折的趋势。

可吸收肋骨钉与记忆合金接骨板内固定治疗多发性肋骨骨折的效果比较

目的探讨可吸收肋骨钉与记忆合金接骨板内固定治疗多发性肋骨骨折的效果。方法选择2009年1月～2013年6月在台州市中心医院胸外科行手术内固定治疗的胸部外伤致多发性肋骨骨折患者70例，随机分为观察组和对照组，每组各35例，观察组采用可吸收肋骨钉内固定治疗，对照组采用记忆合金接骨板进内固定治疗。观察两组患者手术时间、术中失血量、术后镇痛率、术后下床活动时间、术后胸管引流时间、术后住院时间和术中术后并发症的发生率等，术后6个月随访复查x线了解骨折愈合情况。结果观察组患者术后镇痛率[11．43％（4／35）]和术后下床活动时间[（3．82±0．69）d]明显少于对照组[31．43％（11／35）、（5．01±1．04）d]（X2=4．16，t=2．24，P〈0．05）。观察组和对照组患者手术时间[（113．3±28．6）min比（109．4±30．4）minl、术中出血量[（100．4±21．5）mL比（97．6±39．2）mL]、术后胸管引流时间[（5．47±0．82）d比（5．69±0．94）d]、术后住院时间[（10．29±2．06）d比（10．48±2．09）d]和术后并发症发生率[20．00％比14．29％]比较差异无统计学意义（t=0.31、0．40、0．29、0．14，X2=0．40，P〉0．05）。术后6个月随访复查胸部X线，两组患者均无骨折再移位。结论可吸收肋骨钉与记忆合金接骨板均是治疗多发性肋骨骨折较理想的术式。前者在术后镇痛率和术后下床活动时间等方面具有优势，且无需二次手术取出内固定，减轻了患者痛苦。

S形接骨板与形状记忆合金环抱器治疗锁骨中1/3骨折59例疗效分析

目的比较S形接骨板与形状记忆合金环抱器治疗锁骨中1/3骨折的临床疗效。方法2004年9月～2006年10月,笔者手术治疗59例成人锁骨中1/3骨折患者,其中男性38例,女性21例,年龄18～68岁,平均年龄27.8岁。根据临床具体情况随机分为2组,A组31例采用S形接骨板内固定,B组28例采用形状记忆合金环抱器内固定,术后定期随访。根据X线片及肩关节功能恢复情况对比两组手术时间、取出内固定时间、骨折愈合时间及评定疗效。结果A组27例得到随访,B组25例得到随访,骨折愈合后于笔者医院取出内固定置入物,两组手术时间、术后取出内固定时间、骨折愈合时间差异无统计学意义。A组优21例,良5例,可1例;B组优12例,良7例,可5例,差1例;A、B两组优良率分别为96.3%和76.0%,A组疗效明显优于B组。结论S形接骨板是治疗锁骨中1/3骨折的有效方法。

基于形状记忆合金的X形板阻尼器的力学模型

根据超弹性形状记忆合金(SMA)的分段线性化本构关系,建立了X形SMA板式阻尼器的力学模型;通过MATLAB程序进行数值模拟,绘制了X形SMA板的阻尼力滞回曲线,并研究了位移幅值、温度、形状尺寸对阻尼器基本特征参数(等效割线刚度、单位循环消耗的能量、等效阻尼比)的影响。结果表明:X形SMA板式阻尼器具有“旗帜”形的滞回曲线,耗能较小,但复位能力好;随位移幅值增加,耗能力和等效阻尼比增加,等效割线刚度降低,温度的影响与此相反;阻尼器的特征参数随板高增加均呈降低趋势;增加板宽,单位循环耗能与等效割线刚度增加,而等效阻尼比不变。研究结果为X形SMA板式阻尼器的设计和工程应用提供了理论依据。