图示结构中,除横梁外各杆件EI=常数。质量集中在横梁上,不考虑杆件的轴向变形,则体系振动的自由度数为()
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
免费的网站请分享给朋友吧