A state-of-the-art test equipment for characterization of advanced rheological materials

用于表征先进流变材料的最先进的测试设备

• 批准号: RTI-2017-00751
• 负责人: Sedaghati, Ramin
• 金额: $ 8.59万
• 依托单位: Concordia University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616759
• 关键词: state; art; test; equipment; characterization

Magnetorheological (MR) materials are advanced materials whose rheological behavior can be controlled using the applied magnetic field. MR materials can be in liquid (MR fluids) or solid (MR elastomers) states. MR fluids are typically composed of micron-sized magnetically polarizable particles (typically carbonyl iron particles) dispersed in a carrier medium such as mineral or silicone based oils. When exposed to a magnetic field, these magnetic dipoles align themselves along the lines of magnetic flux causing the MR fluid to change from a free-flowing viscous fluid to a semi-solid with controllable yield strength in the order of milliseconds. MR fluids can also be confined in an absorbent matrix such as sponge by capillary action to form MR fluid foams. MR elastomers are rubber-like materials (magnetic particles are suspended in a solid polymeric medium) whose modulus can be adaptively controlled. The ability of MR materials to provide simple, quiet and rapid-response interfaces between electronic controls and mechanical systems have made them attractive materials for new generation of high bandwidth semi-active devices which can be efficiently used to improve the performance of adaptive structural systems under unpredictable environmental changes. MR materials can be effectively utilized to control vibration and structure-born noise in wide range of frequencies and thus allow to design next generation of ground, aerospace and marine vehicles which are cost-effective and reliable while meeting the standards for passenger comfort. To effectively design these MR-based adaptive structures, fundamental understanding of the dynamic behaviour of MR materials under varying applied magnetic field, frequency and amplitude of excitations as well as temperature is of paramount importance. Considering this, the proposed equipment is needed to conduct fundamental and systematic study on the behavior of all types of MR materials under varying intensities of magnetic field and varying external excitations in both pre-yield and post-yield regions. The requested magneto-rheometer is a unique device to characterize the behavior of MR materials under wide range of excitation frequencies and amplitudes, and temperature under the application of external uniform magnetic field intensities which can reach up to 1 Tesla. The linear and nonlinear viscoelastic properties of MR materials as well as their viscoplastic behavior in post-yield region can be investigated using the proposed equipment. This will eventually lead to development of constitutive models that can accurately characterize the rheological behavior of MR materials in different operating regions and thus can be effectively used in modeling of novel MR-based adaptive structures under unpredictable external excitations.

磁流变学(MR)材料是一种可以通过外加磁场来控制其流变行为的先进材料。磁流变材料可以是液体(磁流变液)或固体(磁流变弹性体)。磁流变液通常由微米大小的可磁极化颗粒(通常是羰基铁颗粒)分散在矿物油或硅油等载体介质中组成。当暴露在磁场中时，这些磁偶极子沿着磁通线排列，导致磁流变液从自由流动的粘性液体转变为屈服强度在毫秒量级可控的半固态。磁流变液还可以通过毛细作用被限制在诸如海绵之类的吸收基质中，以形成磁流变液泡沫。磁流变弹性体是一种橡胶状材料(磁性颗粒悬浮在固体聚合物介质中)，其模数可自适应控制。磁流变材料能够在电子控制和机械系统之间提供简单、安静和快速响应的接口，这使得它们成为新一代高带宽半主动器件的诱人材料，可以有效地提高自适应结构系统在不可预测的环境变化下的性能。磁流变材料可以有效地在很宽的频率范围内控制振动和结构噪声，从而允许设计出性价比高、可靠的下一代地面、航空和船舶车辆，同时满足乘客舒适性标准。为了有效地设计这些基于磁流变的自适应结构，基本了解磁流变材料在不同外加磁场、激励频率和幅度以及温度下的动态行为是至关重要的。考虑到这一点，需要该装置对所有类型的磁流变材料在不同的磁场强度和不同的外部激励下的屈服前和屈服后的行为进行基础和系统的研究。所要求的磁流变仪是一种独特的设备，用于表征磁流变仪在高达1特斯拉的外部均匀磁场强度下，在广泛的激励频率和幅度以及温度范围内的行为。利用该装置可以研究磁流变材料的线性和非线性粘弹性特性以及屈服后区域的粘塑性行为。这将最终导致本构模型的发展，该模型可以准确地描述磁流变材料在不同工作区域的流变行为，从而可以有效地用于在不可预测的外部激励下的新型磁流变自适应结构的建模。