【作者】 严柏平；

【导师】 李立毅；

【作者基本信息】 哈尔滨工业大学 ， 电机与电器， 2014， 博士

【摘要】 超磁致伸缩材料（Giant Magnetostrictive Material，简称GMM）是一种可实现磁－机械双向可逆能量转换的智能材料，且材料应用中同时兼具执行和传感功能；基于超磁致伸缩材料的执行器（Giant Magnetostrictive Actuator，简称GMA）具有快速响应、大行程量、负载能力强、高可靠性等特点，在精密驱动、流量控制、阀门结构、主动减振、换能器等高新技术领域具有较好的应用前景。本文以超磁致伸缩执行器为研究对象，针对超磁致伸缩材料内的磁畴角度偏转、磁化和磁弹性等磁机耦合关系以及执行器中有效磁场的优化、感知开展研究，建立了适用于超磁致伸缩执行器自感知应用的材料感知和执行器应用理论。研制了超磁致伸缩执行器，并搭建实验测试平台，实验测评了执行器的应用特性，且对执行器的自感知应用进行验证。研究结果有利于完善超磁致伸缩材料磁机耦合及磁弹性效应的本构模型，研究内容对执行器的自感知应用拓展具有理论指导意义。针对超磁致伸缩材料本构模型中的“磁问题”展开研究。基于自由能极小原理及磁畴偏转理论，采用坐标变换和图解法相结合，研究了超磁致伸缩材料在不同载荷作用下的磁畴偏转、跃迁特性，建立了简化的适用于材料磁感知应用的磁畴偏转数值方法，直观解释了GMM材料在不同载荷作用下的磁致伸缩机理；在此基础上，研究了磁畴偏转数值方法对材料本构参数的参数依赖性。研究结果表明：预压应力有利于压磁效应中90°畴的积累，但不利于磁弹性效应中磁畴的偏转和磁化的进行；[110]取向晶体中磁畴的偏转均可简化为平面内的磁畴旋转，磁畴的跃迁效应为磁畴角度所处平面间的跃迁变化，其中35.3°方向磁畴在压磁和磁弹性效应中的偏转及跃迁是材料具有大磁致伸缩效应的关键；各项异性常数K1和K2的不同取值将影响材料磁畴偏转特性和磁畴角度跃迁的临界载荷值，且材料磁畴偏转数值方法对磁晶各向异性常数和能量分布因子等具有明显的参数依赖性。在磁畴偏转数值方法的基础上，研究了超磁致伸缩材料磁机能量耦合中的磁弹性效应。通过实验测试完成超磁致伸缩材料磁畴偏转数值方法的本构参数辨识，完善了材料的磁畴偏转模型；在此基础上，研究载荷作用下磁畴偏转的磁机耦合理论及应变量输出特性；分析磁机耦合过程中的能量转换关系，建立输入－输出载荷参量间二端口网络的等效电路关系，论证基于磁畴偏转数值方法的材料自感知可行性，为执行器自感知的应用提供理论指导。其中，修正的磁畴偏转数值方法能够较好描述超磁致伸缩材料的磁化和应变量特性，进一步论证了压应力对压磁和磁弹性效应的贡献，压应力将增大材料的有效磁致伸缩应变，但达到同等应变量需更大的磁场载荷；研究内容完善了材料的磁机耦合理论，为超磁致伸缩执行器的自感知应用设计及论证提供基础理论指导。针对超磁致伸缩执行器中的磁和热问题展开研究，完成执行器自感知应用的设计优化和磁场感知关系的建立。解析优化超磁致伸缩执行器中励磁线圈结构及空间磁场分布，研究了考虑超磁致伸缩材料磁导率下执行器内有效磁场分布，修正材料轴向磁场分布的不均性，建立了考虑GMM磁导率下精确的励磁电流－磁场间的数学关系；计算分析超磁致伸缩执行器内的损耗和热传递，仿真明确不同励磁状态下GMA中温升特性；建立执行器中励磁线圈磁感知的数学关系，完善超磁致伸缩执行器的感知应用模型。研究结果表明：超磁致伸缩材料磁导率的不同取值将影响材料轴向磁场分布，其中，GMM材料的端部磁场将高于中间位置，且磁导率的增加有利于增强轴向磁场的均匀性，同时使得材料内平均磁场的数值减小。最后，设计制作了超磁致伸缩执行器，搭建实验测试平台。完成超磁致伸缩材料及其执行器输出机械特性、温度特性、动态特性的测试评价，论证了超磁致伸缩材料感知模型和执行器自感知应用模型的正确性。结果表明，所设计的超磁致伸缩执行器在15MPa压应力作用下，能够实现大于45μm、3.6MPa冲击力输出，其最大输出应力达到12.5MPa；GMA在静态、动态励磁下均存在应变量的滞回，且滞回重复性较好，其动态谐振频率在1200Hz左右，磁机耦合系数达0.572；在超磁致伸缩自感知验证中，预压应力载荷的感知误差为0.5~0.6的标准差，应变量感知数值与实测结果的最大误差小于2.5μm，重复试验误差约1μm，论证了所建立磁畴偏转数值方法的正确性和自感知应用的可行性。更多还原

【Abstract】 As a new kinds of smart material, Giant magnetostrictive material (GMM) canmake energy conversion between magnetic and mechanical reversible, has bothactuator and sensor function. The giant magnetostrictive actuator (GMA) based onGMM has many merits, such as quick response, large strain, heavy load, and highprecision, etc. It has good application in the field of precision drive, flow control,valve control, damping, energy converter. The angle deflection of magnetic domain,magnetization, magnetostriction of GMM is studied in this paper, optimization andsensing relation of effective magnetic field in GMA is analyzed, then sensingrelation of GMM and application theory of GMA suit for self-sensing application isestabilished. A small structure GMA is manufactured, and the test platform isconstructed. Application characteristics of GMA are calculated in experiment, usedto prove the self-sensing model of GMA. The research results could be adopted inconsummating the constitutive model of GMM magnetomechanical coupling andmagnetostriction. The GMA constructed in this paper would have good applicationvalue in micro flow control valve, and the works also have theoretical significancefor the self-sensing application of GMA.Firstly, magnetization of the constitutive model in GMM is studied in thispaper. Based on the minimum principle of free energy and theory of magneticdomain deflection, the angle rotation and jump effects of magnetic domain in GMMwith input loads are analyzed, used technology of coordinate conversion andgeometry solution. Then a simple numerical analysis method of the magneticdomain deflection is established for self-sensing application, which can directlyreveal magnetostricitive effects of GMM with different input loads. Based on thosetheories, the parameter dependence of numerical method in magnetic domaindeflection is studied, used to perfect magnetic domain deflection numercial methodof GMM. The research results indicate that piezomagnetic effect of GMM is helpfulfor domain accumulation in90°direction, not advantage for moment rotation andmagnetization in magnetostriction. Magnetic domain deflection of [110] orientationcrystal would be simplify to plane rotation, and jump effect happened betweenplanes of reversible domain rotation, in which the rotation and jump effects of35.3°angle domain is the key factor of GMM in piezomagnetic effect andmagnetostriction. Different anisotropy constant K1and K2could influence thecritical load value of angle jump effect in magnetic domain rotation, and numericalmethod of magnetic domain deflection has obvious dependence on the anisotropy constant and energy distribution factors.Based on the analysis of magetic domain deflection, the magnetostriction ofGMM in the magnetomechanical coupling process is studied. The constitutiveparameters identification of GMM in domain deflection numerical method arefinished by experimental result, that could consummate the domain deflectionmodel. Then, the magnetomechanical coupling theory and strain outputcharacteristic based on domain rotation are researched with input loads. The energyconversion are analyzed in the process of magnetomechanical coupling, andtwo-port equivalent circuit of energy conversion is established. The feasibility ofself-sensing application of GMM based on domain deflection numerical method isanalyzed, used to support the theoretical guiding for actuator self-sensingapplication. More that, correctional domain deflection numerical method coulddescribe magnetization and magnetostriction characteristic of GMM, prove effectthat large pressive stress could increase the effective output strain inmagnetostriction, and need larger magnetic field loads for domain rotation and itsmagnetization. The research result consummates the magnetomechanical couplingtheory, and it would support the theorical guiding for actutor self-sensing designand application.Thirdly, the magnetic and thermal problem in GMA are also studied,mathematics function between the magnetic field and magnetic sensing in actuatorsensing application are constructed. Structure of driving coil and space magneticfield in the GMA are optimized. The effective magnetic field distribution in thecondition of GMM permeability is analyzed, axial magnetic field anisotropy ofmaterial is revised, used to establish the function between driving current andmagnetic field with consideration of GMM permeability. Magnetic loss and heattransformation in GMA are studied, and thermal characteristics with differentcurrent conditions are simulated. The function of magnetic sensing in GMA isestablished, used to consummate self-sensing model for the GMA application. Theresearch results describe that different GMM permeability value would influencedistribution of axial magnetic field in material, special the magnetic field interminal part is larger than the center part, and large GMM permeability valuewould increase the uniformity of axial magnetic field and decrease the averagemagnetic field in the material.Finally, the GMA prototype is designed and manufactured, the test platform isestablished. The output strain, output impact force, temperature characteristics aretested in this platform, the dynamic characteristic with different frequency isstudied. Experiments prove the validity of GMM sensing relation and GMA self-sensing application model. Results indicate that the GMA has3.6MPa impactstress and45μm output mechanical characteristic in the condition of15MPa pressstress, and it would has maximum12.5MPa output stress. The GMA designed in thispaper is suitable for the large strain load in actuator and damping field application.GMA has hysteresis with static and dynamic driving current, and has goodrepetition hysteresis curves. Its first dynamic syntony frequency is1200Hz, andmagnetomechanical coefficient could up to0.572. Specially, below the syntonyfrequency, the strain should have the positive frequency coefficient, the straindecreases against increasing frequency under larger syntony frequency. In thevalidation of GMM self-sensing, the deviation of pressive stress could reach0.5~0.6, and the maximum error between the self-sensing and test value is below2.5μm, the repeated test error of experimentals is approximately1μm. Those resultscould prove the validity of numerical method in domain deflection and feasibility ofself-sensing application in GMA.更多还原