(完整版)Impact Materia
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Impact Material
This command is used to construct an impact material object
＄matTag integer tag identifying material
$K1initial stiffness 初始刚度
＄K2secondary stiffness 屈服后刚度
＄δy yield displacement 屈服位移
＄gap initial gap* 初始间隙
NOTES:
This material is implemented as a compression—only gap material。
Delta_y and gap should be input as negative values。
＄δy、$gap都为负值。
DESCRIPTION:
This material is based on an approximation to the Hertz contact model proposed by Muthukumar (See REFERENCES below）. The energy dissipated during impact is:
E = k h＊δm^(n+1) ＊（1—e^2) / (N+1)
is the impact stiffness parameter, with a typical value of EA/L or 25,000 k-in。
where k
h
-3/2；n is typically taken as 3/2 for the exponent associated with the Hertz power rule；e is the coefficient of restitution, with typical values from 0。
6-0。
8; and δm is the maximum penetration during the pounding event。
n：3/2 ；e:恢复系数，取值:0。
6～0。
8；δm：最大侵入深度（最大侵入深度为假设值,并不是实际的侵入深度）.
The effective stiffness, K eff， is： K eff = k h＊(δm)^0。
5
The yield displacement is:
δy = a ＊δm
where a is typically taken as 0。
1。
The initial stiffness， K1, and secondary stiffness；K2, are then selected such that the Impact model dissipates an amount of energy during a pounding event that is consistent with the associated energy dissipated in the Hertz model。
K1 = K eff+ E / (a*δm^2)
K2 = K eff - E / （(1-a）＊δm^2）
Response of Impact Material during a pounding event. Response of Impact Material for displacement cycles of increasing amplitude
你可参考一下文献：
A contact element approach with hystersis damping for the analysis and design of pounding in bridges 以及研究生论文：简支梁斜交梁桥非线性地震反应分析与控制。