共查询到19条相似文献,搜索用时 694 毫秒
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通过仿真优化与试验,研制了一套用于承压类管道内壁损伤检测的系统,系统由低频电磁传感器模块、信号发生模块、功率放大模块以及信号调理模块构成。通过低频电磁传感器磁化管道并采集管道的电磁信号,由信号发生和功率放大模块完成对激励线圈的励磁,信号调理模块完成数据放大和滤波,最终实现管道内部缺陷检测。试验结果表明,该低频电磁检测系统灵敏度高,可以实现对直径为152 mm,厚度为16 mm,埋深为12.8 mm的304不锈钢承压管道内部缺陷的有效检测,且其最佳检测频率为100 Hz~200 Hz。 相似文献
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磁场力分析是电磁成形理论分析的基础,其分析结果直接用于工件的变形分析.应用FEA软件ANSYS对平板件电磁成形磁场进行数值计算,分析了板坯上磁场分布特点及放电电压和脉冲电流频率对磁场力的影响.进行了锥形件电磁成形试验,验证了有限元模拟方法用于平板件电磁成形磁场力模拟的有效性. 相似文献
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对电磁铸造圆形感应器产生的磁场在金属熔体内的电磁作用力进行了理论分析和实验研究。指出导体中电磁作用力仅存在于径向及轴向方向上。电磁作用力的大小不仅与磁感应强度有关,还与磁感应强度的分布梯度有关;电磁有旋力是由于磁场分布不均匀造成的,其旋度方向在柱坐标系的周向方向上。试验研究分析了感应器结构、电流等工艺参数对电磁场分布的影响。 相似文献
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研究交变磁场下的焊缝裂纹磁化规律,针对碳钢(Q235)焊缝裂纹,进行交变电磁场励磁下焊缝磁光成像无损检测的仿真和试验. 基于交变励磁下焊缝励磁规律的仿真模型,研究裂纹间隙分别为0.03,0.05,0.07和0.1 mm的焊缝表面磁通密度(磁感应强度)模曲线分布差异. 钢板对接间隙分别限定为0.03,0.05,0.07和0.1 mm后,通过激光焊接钢板两端来模拟仿真试验中的裂纹. 进行磁光成像无损检测试验,并将试验结果与仿真结果进行对比. 结果表明,在仿真试验与工艺试验中,焊接裂纹感应磁场的变化规律基本相同,磁感应强度不会因采样起始点不同出现较大的差异. 相似文献
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Saeed Kahrobaee Mehrdad KashefiAlireza Saheb Alam 《Surface & coatings technology》2011,205(16):4083-4088
From practical point of view, determining the decarburizing depth is important in quality control of steel parts as it has undesirable effects on the mechanical properties such as hardness, wear and fatigue resistance. Traditional destructive methods of determining the depth of decarburized layer include metallographic and hardness test which are time-consuming and costly. Since response to eddy current is sensitive to chemical composition as well as microstructure of the material under consideration, the non-destructive method can be used in determining the depth of the decarburized layer in steel parts. It is mainly due to the difference in the microstructures, and as a result, in the magnetic properties of the decarburized layer with other parts of the specimen. In the present study at the first step, the magnetic properties of decarburized carbon steel bars (0.45 wt.% C) were evaluated using an electromagnetic sensor and correlated with the microstructure changes from surface to the core of the sample. At the second step the steel bars were held in 900 °C for different period of times and the depth of decarburizing layers were measured using hardness testing. Finally, the non-destructive eddy current technique was used and the response of test samples to the induction current including primary and secondary voltages, normalized impedance, phase angle and harmonic analysis parameters were investigated. Results show an acceptable accuracy in comparison to the destructive method. 相似文献
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U. Nürnberger 《工业材料与腐蚀》2012,63(12):1173-1180
The contribution is dedicated to the durability of geotechnical stabilization applications. The long‐term corrosion behavior of unprotected and galvanized thread‐bars for micro‐piles and nails in different soils is described. The bars in the ground are embedded in an up to 20 mm thick cement mortar, which may be cracked and locally destructed. First, the corrosion‐affecting parameters of the steel corrosion in the ground are described and soil classes are defined. Furthermore, an estimation of the long‐term (up to 50 years) corrosion behavior was assessed on the base of information from the literature. Here the corrosion of the thread‐bar in direct contact with the soil was in the center of interest. The corrosion protection of the cement mortar cover was not taken into consideration, in order to be on the safe side. On the other hand, a macrocell‐corrosion of the thread‐bars cannot be completely excluded, if the cement mortar casing exhibits defects and constructional and environmental corrosive conditions in the ground are fulfilled. Two cases are discussed: ? element formation between sections along the thread‐bar, ? element formation between the thread‐bar and other reinforced concrete parts. 相似文献
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为测试汽车空调控制面板的性能,保证汽车空调的优异操纵性能,基于VC设计了汽车空调控制面板性能测试系统。对系统测试原理进行阐述,采用平衡状态下的扭矩平衡原理及牛顿第二定律等对空调面板等进行测试,并与理论设计数值进行对比。并对某型号的空调面板进行测试,结果表明:检测数据准确,检测系统各部分性能稳定。此系统可以对空调控制面板性能进行有效的检测,在汽车空调配件厂有很高的应用价值。 相似文献
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精密管材和棒材广泛用于核能和航空航天等领域,其细微缺陷探伤和尺寸精密测量极为重要。为此研制了精密管棒材数字成像无损探伤和测量系统。该系统由超声纵、横向缺陷探伤、超声尺寸测量、涡流探伤等子系统组成,实现了管材内壁、外壁纵横向缺陷超声探伤,棒材内部缺陷超声纵波探伤,棒材纵向缺陷超声横波探伤;棒材周向、径向缺陷超声横波探伤;管材壁厚超声测量,管材、棒材直径超声测量,管材、棒材椭圆度超声测量;管材、棒材缺陷涡流穿过式探伤及异物(渗碳等)检测,管材、棒材材料背景噪声穿过式涡流检测,管材、棒材旋转点式涡流探伤。各检测子系统均依据轴向编码器和周向编码器进行缺陷检测和尺寸测量的时基线记录显示、B扫显示和C扫成像显示,实现了高灵敏度、高分辨力、高可靠性的管材和棒材无损检测。 相似文献
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为方便对矿用减速器进行空载试验、负载试验、温升试验、油压测量试验和振动实验,设计了减速器性能测试试验台,主要进行了数据采集系统和驱动电机变频调速系统的设计。该实验台控制精度高、性能稳定、安全可靠、操作方便,在矿山机械、煤矿机械、水泥机械等相关行业中有重要的使用价值。 相似文献