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Development of a 14T MRI magnet with a 900 mm warm bore was initiated by the Hefei Institute of Physical Science, Chinese Academy of Sciences. The homogeneity of the MRI magnet is less than 0.5 ppm in the spherical space with 22 cm diameter. A type of conductor like 11.7 T MRI Magnet is developed, which is called Rutherford cable in Channel (RIC). RIC conductor is subjected to huge electromagnetic loads and mechanical load during the operational period. Excessive strain occurred in Nb3Sn cable will lead to degradation of cable performance. This paper is focusing on the conductor mechanical analysis of the 14 T MRI magnet systems. Firstly, a ‘unit cell’ finite element (FE) model of the channel and insulation is built based on the conductor we designed. Then the equivalent material properties used for 14 T MRI main magnet are calculated according to the generalized Hooke's law. Finally, a quarter FE model is created based on the structural design of magnet system with the preload structure to investigate the stress and strain of conductor under the different operating conditions.

With the development of environmental energy harvesting technology, the research focus gradually develops from the energy harvester itself to the energy harvesting system of coupled environmental vibration sources, in which environmental airflow energy harvesting technology based on the piezoelectric effect is an important research direction. Here, the study status and development trend of piezoelectric energy harvesting were reviewed and summarized including rotation types, vortex-induced vibration types, flutter types and resonant types. It was found that the rotational multi-array energy harvesters are easy to scale, and the vortex-induced vibration and the flutter energy harvesters are poor adaptability for wide range of airflow velocity, and the resonant types can effectively improve excitation energy and output power. In order to improve power generation capacity and broaden the range of airflow velocity, energy harvesting with multiple frequency excitation and multi-piezoelectric array are future main development tendencies.

The Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) has announced a project to design and manufacture a high field MRI magnet with a 900 mm warm bore and comprised of Nb3Sn Rutherford cables in 2017. The maximum magnetic induction of magnet system is 14.3 T and magnetic field homogeneity in a spherical volume with 22 cm diameter is better than 0.5 ppm. The high performance Nb3Sn strand is the potential options to use for such high field magnet system. ASIPP cooperates with Western Superconducting Technologies Company (WST) to develop high performance Nb3Sn strand whose critical current density Jc is higher than 2000 A/mm2 at 4.2 K, 12 T. To obtain the actual performance of WST high performance Nb3Sn strand, three short samples are prepared with different non-copper ratio or different heat treatment, the critical current Ic or quench current of all sample is measured at different field by the voltage-current (V-I) method, the residual resistivity ratio (RRR) of all sample is also measured. To study the strand whether it will be affected by low field instability, a small coil is built with WST strand, and the experimental result is presented and discussed in this paper.

In 2017,The Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) has announced a project to develop a 14 T MRI for the research of brain science and neurology. A type of conductor like 11.7 T MRI Magnet is developed for main coil of 14T MRI, which is called Rutherford cable in channel (RIC). Conductor of 14 T MRI magnet is subjected to huge electromagnetic loads and mechanical load during the operational period. During the design, the material properties of conductor must be obtained to predict the stress-strain behavior accurately to simplify the finite element (FE) model. This paper proposes a finite element method for predicting equivalent properties of 14 T MRI main coil. Then a global finite element model of a small model coil is built to verify the effectiveness and accuracy of this method.

The Institute of Plasma Physics Chinese Academy of Sciences (ASIPP) has announced a project to design a 14 T MRI magnet with a 900 mm warm bore and comprised of Nb3Sn Rutherford cables, the homogeneity of the magnetic field is better than 0.5 ppm in a 22 cm diameter spherical volume. The coil is composed of many types of material and periodic microstructure. It is important to predict its equivalent material properties for mechanic analysis during design stage. A method commonly used is finite element method (FEM) based on Generalized Hook's Law was proposed.

This paper analyzes the operating characteristics of the crawler crane and summarizes distributed sources in the process of fatigue crack propagation of the boom, makes an introduction of evaluation process of the boom of the remaining life. Three static reliability analysis models are analyzed; the evaluation of reliability indicators do not change over time, and the defect is pointed out that they cannot be satisfied to solve practical engineering problems. This article regards the load and fatigue resistance as a random process and considers the fatigue failure of the randomness in a variety of factors, the concept of dynamic reliability of the weight index is proposed, and models of dynamic reliability of the weight index are built based on the fatigue bearing capacity mode and limit damage degree mode. By computational analysis of the two models and test comparison of the standard welding components, the remaining fatigue life under the dynamic reliability of the weight index model prediction accuracy higher than the static reliability indicators of prediction accuracy. This method provides a new thinking and new methods for the detection and evaluation of the fatigue life of crane booms.

Characteristic of All-Terrain Crane (ATC) is introduced in this paper and the working principle of Hydro-Pneumatic Suspension (HPS) in ATC is also discussed. The development status and tendency are summarized, through which we can see there is a large technology gap between China and Western Europe. An optimization method to HPS based on ADAMS is introduced in the paper. Based on ADAMS, a single bridge HPS of All-Terrain Crane virtual prototype is built and the function of HPS is accomplished with the standard hydraulic components. By the method of Design of Experiments (DOE), the dynamics optimization of HPS is carried out based on the analysis of the affecting factors after optimization variables are chosen. At last the result indicates that the dynamics characteristic of optimized model performs better than the former one and the present method can be used as a structural optimization reference.Copyright © 2008 by ASME