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落锤作用下磁铁矿石冲击破碎特征的能比效应
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作者 甘德清 于泽皞 +1 位作者 刘志义 孙海宽 《金属矿山》 北大核心 2025年第2期48-55,共8页
为了确定利于磁铁矿石破碎的加载能量,确保破碎粒度达标的同时提高有效能量占比,从而提高矿山破碎作业中的能量利用率。通过改变落锤冲击高度,探究了不同冲击能比下磁铁矿石的强度特征、破碎能量变化规律以及破碎粒度分布特点。研究表明... 为了确定利于磁铁矿石破碎的加载能量,确保破碎粒度达标的同时提高有效能量占比,从而提高矿山破碎作业中的能量利用率。通过改变落锤冲击高度,探究了不同冲击能比下磁铁矿石的强度特征、破碎能量变化规律以及破碎粒度分布特点。研究表明:磁铁矿石的冲击力时程曲线分为冲击力急速提升、平稳作用、回落、回升与震荡四个阶段,平稳作用阶段持续时间最长,可达9~10 ms,试件所受冲击强度随冲击能比增加线性升高;随冲击能比增加,磁铁矿石吸能效率先增后减,再增再减,存在吸能效率较高的能比范围,矿石吸收能、吸收能密度均呈线性趋势增加,使得矿石起裂时的裂纹由单一张拉裂纹转为拉伸剪切交织裂纹,破碎方式也由拉伸破坏逐渐转向压缩剪切破坏,磁铁矿石的破碎程度逐渐加剧;冲击能比增加降低了破碎产品的大块率,使得破碎产品粒度更加均匀,粒度分形维数线性增加,碎块平均粒径呈指数趋势减小,破碎产品细度t_(10)以缓—急—缓的趋势增加。研究结果对优化矿山破碎机械参数、提高磁铁矿石破碎效率具有一定的指导意义。 展开更多
关键词 磁铁矿石 冲击能比 强度变化 能量特性 破碎特征
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Theoretical and experimental study of a compact energy absorption structure
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作者 WANG Yan-jing SUN Cheng-ming +2 位作者 CHEN Fei-peng YAO Shu-jian SUN Hong-ji 《Journal of Central South University》 2025年第7期2766-2780,共15页
The advancement of rail transportation necessitates energy absorption structures that not only ensure safety but also optimize space utilization,a critical yet often overlooked aspect in existing designs.This study pr... The advancement of rail transportation necessitates energy absorption structures that not only ensure safety but also optimize space utilization,a critical yet often overlooked aspect in existing designs.This study presents a compact energy absorption structure(CE)that integrates the advantages of cutting rings and thin-walled tube modules,offering a solution with the high space utilization and the superior crashworthiness.Through theoretical modeling and experimental validation using a drop-weight test system,we analyzed the dynamic response and energy absorption characteristics of the CE.Comparative analysis with existing structures,namely the cutting shear rings(CSR)energy absorption structure and thin-walled tube structure(TW),revealed that the CE significantly improves specific energy absorption(SEA)by 102.76%and 61.54%,respectively,and optimizes crush force efficiency(CFE)by increasing 8.23%and 5.49%compared to CSR and TW.The innovative design of the CE,featuring deformation gradient and delay response strategies,showcases its potential for practical application in engineering,advancing the field of crashworthiness engineering. 展开更多
关键词 energy absorption structure drop-weight test impact dynamics specific energy absorption crush force efficiency
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