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effect of microstructure on fatigue behavior of intact rocks under completely reversed loading
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نویسنده
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jamali zavareh s. ,baghbanan a. ,hashemolhosseini h. ,haghgouei h.
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منبع
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روشهاي تحليلي و عددي در مهندسي معدن - 2017 - دوره : 6 - شماره : Special - صفحه:55 -62
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چکیده
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Rock formations and structures can be subjected to both static and dynamic loadings. static loadings resulting from different sources such as gravity and tectonic forces and dynamic forces are intermittently transmitted via vibrations of the earth’s crust, through major earthquakes, rock bursts, rock blasting and drilling and also, traffic. reaction of rocks to cyclic and repetitive stresses resulting from dynamic loads has been generally neglected with the exception of a few rather limited studies. in this study, , two crystalline quarry stones in iran; (natanz gabbro and green onyx) and one noncrystalline rock (asmari limestone) are used to evaluate the effect of microstructure of intact rock on fatigue behavior. these rocks have different mineral compositions and formation conditions. a new apparatus based on rotating beam fatigue testing machine (r.r.moore), which is commonly used for laboratory fatigue test in metals, is developed and fatigue behavior and existence of the endurance limit were evaluated for the mentioned rocks based on stresslife method. the obtained results in the variation of applied amplitude stress versus loading cycle number (sn diagram) followed common relationship in other materials. in addition, the endurance limit is perceived for all tested rocks. the results also illustrated that the endurance limits for all types of tested rocks in this study are ranged between 0.4 and 0.6 of their tensile strengths. the endurance limit to tensile strength fraction of green onyx and natanz gabbro were approximated in a higher value compared to the asmari limestone with noncrystalline microstructure.
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کلیدواژه
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fatigue of rocks ,microstructure of intact rocks ,stress – life method ,completely reversed loading ,endurance limit
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آدرس
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isfahan university of technology, deptartment of mining, ایران, isfahan university of technology, deptartment of mining, ایران, isfahan university of technology, deptartment of mining, ایران, isfahan university of technology, deptartment of mining, ایران
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Authors
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