sel cable id=1 begin=(20.63,1.5,16.24) end=(10.11,1.5,13.03) nseg=12
sel cable id=1 begin=(10.11,1.5,13.03) end=(5.33,1.5,11.57) nseg=4
sel cable id=1 prop xcarea = 1.256e-3 emod = 45e9 ytension = 60e4 gr_k = 0 gr_coh = 0 gr_fric 0 gr_per = 0.314 range cid 1,12
sel cable id=1 prop xcarea = 1.256e-3 emod = 45e9 ytension = 60e4 gr_k = 2.75e7 gr_coh = 2.2e4 gr_fric = 20 gr_per = 0.314 range cid 13,16
sel delete link range id=1
sel link id=1 1 target zone
sel link attach xdir = rigid ydir = rigid zdir = rigid xrdir = rigid yrdir = rigid zrdir = rigid range id 1
sel cable id=1 pretension 1e5 range cid 1 12
这段命令里面的红色字体的两个参数，是如何确定的？ytension = 60e4 是拉力设计值还是什么？pretension 1e5是锁定值吗？求解释。
