响应谱
10.1 概述响应谱是将单自由度系统的最大响应描述为基础激励的共振频率的函数响应一般形式每个单自由度振子的峰值响应由x(t)计算，振子的运动uB由力或作用到大结构上的基础激励给出假设为振子的质量与振动质量相比非常小，因此两者间无动态干扰。
阻尼作用到每个振子上，而不是作用到振动结构上每个振子的最大位移响应由X(t)计算，在振子和其基座间（振动结构上的一个点）的相对位移也这样计算对低频振子（）
对高频振子
10.2 响应谱求解控制输入执行控制情况控制
如：
该命令根据卡片DT1，SPSEL的记录1,在结点1处x(T1)方向产生一组绝对加速度谱数据模型
Example Input
Sample Input
PARAM RSPECTRA 0
$
$ Tells MSC/NASTRAN to perform spectra creation
$
$ RECNO DAMP FREQ G1 G2 G3 G4
DTI SPSEL 1 1 2 1 2 3 4 +SPSEL1
+SPSEL1 ENDREC
$
$ Tells the program that if RECNO 1 is selected by the XYPLOT command,
$ then DAMPing set 1 and FREQuency set 2 are to be used for GRIDs 1,
$ 2,3,and 4 (if requested)
$
FREQ 1 0.,01,02
$
$ This is the FREQ entry used by SPSEL RECNO 1 to specify damping ratios
$ to be used,In this case,spectral will be generated for damping
$ ratios of 0%,1%,and 2% of critical
$
FREQ1 2,5,5 200
$
$ This is the FREQ entry used by SPSEL RECNO 1 to specify the
$ frequencies at which data points on the spectra will be
$ generated,In this case,spectra points will be generated
$ for oscillators with natural frequencies of,5Hz to 100.5Hz
$ by increments of,5 Hz
10.3 响应谱应用
1）应用于SOL 103
“Poor mans’ transient.” 用于确定每阶模态的峰值响应峰值模态响应组合得到系统响应组合模态响应有三中方法(ABS,SRSS,NRL)
2) 过程在结构上找出输入点的SUPORT’ DOF
附加大质量到该SUPORT’ DOF.
得到SUPORT DOFs未约束系统模态(包括0.0 Hz模态)
估计附加在激励结构上的自由模态
3) 应用
(a) Xr为单自由度振子由于基座运动引起的响应
在物理点实际响应为
对ABS方法其中，
I代表模态，r代表方向
对SRSS方法其中，
对NRL方法其中，
10.4 求解控制执行控制情况控制
例：
数据模型
输入示范
SUPORT 1 3
$
$ Define input dof for the spectra - in this case,dof 3 for GRID 1 is selected
$
CONM2 1001 3 0 1000000.
$
$ apply large masses in the directions of the spectra input
$
TABDMP1 1 CRIT +DMP1
+DMP1 0.0,01 100.,01 100.01,02 1000.,02 +DMP2
+DMP2 ENDT
$
$ Select damping ratios for the calculated modes - in this case,a ratio of 1% of ctrtical $ is used for all modes from 0hz to 100hz and 2% of critical is used for all modes above $ 100.01hz
$
$
PARAM,SCRSPEC,0
$ Tells MSC/NASTRAN to perform shock spectrum analysis
$ DEFINE WHERE AND HOW TO APPLY SPECTRA
$
$ NOTE THAT SPECTRA ARE APPLIED USING INTERNAL SORT...NOT ASCENDING
$ ORDER
$
$ SID S S1 L1 S2 L2,...
DLOAD 1 1.0 1.0 1
$
$ Define where spectra are to be applied - this entry is called from Case Control by a $ ’DLOAD=1’ command - for this entry,an overall scale factor of 1.0 (S) is applied,$ a factor of 1.0 (S1) is used to apply spectrum 1 (L1) at ’SUPORT’ dof 1.
$
$ (It should be noted that the order of the ’SUPORT’ dof used on this
$ entry is the MSC/NASTRAN internal sort,If only one GRID point is used,
$ this is no problem,but if more than one GRID point is used,
$ then PARAM,USETPRT,1 should be used to obtain the internal order)
$
DTI SPECSEL 0
DTI SPECSEL 1 A 2 0.0 3,01 +SP1
+SP1 4,02
$
$ This table defines the relationship between the input tables
$ (from the spectrum creation run) and the spectra sets,For example,
$ record 1 defines a spectra set representing acceleration spectra,
$ containing spectrum 2 for 0% of critical damping,spectrum 3 for 1% of
$ critical damping,and spectrum 4 for 2% of critical damping.
$ The program will interpolate between the spectra if a mode has a
$ damping value other than those defined in the table.
$
$ GRID Component (XYPLOT terminology)
$ACCE 0 1 3 1
$ 0.000000E+00
TABLED1 2
.5 3.156-4 1.0,001263 1.5,002842 2.,005056
2.5,007905 3.,011393 3.5,015524 4.,020303
4.5,025738 5.,031839 5.5,038615 6.,046073
6.5,054219 7.,063052 7.5,072569 8.,082766
.
.
.
100.5 3.87229 ENDT
$ Table representing the input spectra
10.1 概述响应谱是将单自由度系统的最大响应描述为基础激励的共振频率的函数响应一般形式每个单自由度振子的峰值响应由x(t)计算，振子的运动uB由力或作用到大结构上的基础激励给出假设为振子的质量与振动质量相比非常小，因此两者间无动态干扰。
阻尼作用到每个振子上，而不是作用到振动结构上每个振子的最大位移响应由X(t)计算，在振子和其基座间（振动结构上的一个点）的相对位移也这样计算对低频振子（）
对高频振子
10.2 响应谱求解控制输入执行控制情况控制
如：
该命令根据卡片DT1，SPSEL的记录1,在结点1处x(T1)方向产生一组绝对加速度谱数据模型
Example Input
Sample Input
PARAM RSPECTRA 0
$
$ Tells MSC/NASTRAN to perform spectra creation
$
$ RECNO DAMP FREQ G1 G2 G3 G4
DTI SPSEL 1 1 2 1 2 3 4 +SPSEL1
+SPSEL1 ENDREC
$
$ Tells the program that if RECNO 1 is selected by the XYPLOT command,
$ then DAMPing set 1 and FREQuency set 2 are to be used for GRIDs 1,
$ 2,3,and 4 (if requested)
$
FREQ 1 0.,01,02
$
$ This is the FREQ entry used by SPSEL RECNO 1 to specify damping ratios
$ to be used,In this case,spectral will be generated for damping
$ ratios of 0%,1%,and 2% of critical
$
FREQ1 2,5,5 200
$
$ This is the FREQ entry used by SPSEL RECNO 1 to specify the
$ frequencies at which data points on the spectra will be
$ generated,In this case,spectra points will be generated
$ for oscillators with natural frequencies of,5Hz to 100.5Hz
$ by increments of,5 Hz
10.3 响应谱应用
1）应用于SOL 103
“Poor mans’ transient.” 用于确定每阶模态的峰值响应峰值模态响应组合得到系统响应组合模态响应有三中方法(ABS,SRSS,NRL)
2) 过程在结构上找出输入点的SUPORT’ DOF
附加大质量到该SUPORT’ DOF.
得到SUPORT DOFs未约束系统模态(包括0.0 Hz模态)
估计附加在激励结构上的自由模态
3) 应用
(a) Xr为单自由度振子由于基座运动引起的响应
在物理点实际响应为
对ABS方法其中，
I代表模态，r代表方向
对SRSS方法其中，
对NRL方法其中，
10.4 求解控制执行控制情况控制
例：
数据模型
输入示范
SUPORT 1 3
$
$ Define input dof for the spectra - in this case,dof 3 for GRID 1 is selected
$
CONM2 1001 3 0 1000000.
$
$ apply large masses in the directions of the spectra input
$
TABDMP1 1 CRIT +DMP1
+DMP1 0.0,01 100.,01 100.01,02 1000.,02 +DMP2
+DMP2 ENDT
$
$ Select damping ratios for the calculated modes - in this case,a ratio of 1% of ctrtical $ is used for all modes from 0hz to 100hz and 2% of critical is used for all modes above $ 100.01hz
$
$
PARAM,SCRSPEC,0
$ Tells MSC/NASTRAN to perform shock spectrum analysis
$ DEFINE WHERE AND HOW TO APPLY SPECTRA
$
$ NOTE THAT SPECTRA ARE APPLIED USING INTERNAL SORT...NOT ASCENDING
$ ORDER
$
$ SID S S1 L1 S2 L2,...
DLOAD 1 1.0 1.0 1
$
$ Define where spectra are to be applied - this entry is called from Case Control by a $ ’DLOAD=1’ command - for this entry,an overall scale factor of 1.0 (S) is applied,$ a factor of 1.0 (S1) is used to apply spectrum 1 (L1) at ’SUPORT’ dof 1.
$
$ (It should be noted that the order of the ’SUPORT’ dof used on this
$ entry is the MSC/NASTRAN internal sort,If only one GRID point is used,
$ this is no problem,but if more than one GRID point is used,
$ then PARAM,USETPRT,1 should be used to obtain the internal order)
$
DTI SPECSEL 0
DTI SPECSEL 1 A 2 0.0 3,01 +SP1
+SP1 4,02
$
$ This table defines the relationship between the input tables
$ (from the spectrum creation run) and the spectra sets,For example,
$ record 1 defines a spectra set representing acceleration spectra,
$ containing spectrum 2 for 0% of critical damping,spectrum 3 for 1% of
$ critical damping,and spectrum 4 for 2% of critical damping.
$ The program will interpolate between the spectra if a mode has a
$ damping value other than those defined in the table.
$
$ GRID Component (XYPLOT terminology)
$ACCE 0 1 3 1
$ 0.000000E+00
TABLED1 2
.5 3.156-4 1.0,001263 1.5,002842 2.,005056
2.5,007905 3.,011393 3.5,015524 4.,020303
4.5,025738 5.,031839 5.5,038615 6.,046073
6.5,054219 7.,063052 7.5,072569 8.,082766
.
.
.
100.5 3.87229 ENDT
$ Table representing the input spectra
