重庆时时彩后一必中|重庆时时彩的规律

振动压实系统英文文献和中文翻译

时间:2017-07-09 21:06来源:毕业论文
在振动压实中动态系统与不对称滞回特性的数学建模与特性分析英文文献和中文翻译
Abstract We investigate dynamic characteristics of
vibratory compaction system with asymmetrical hys-
teresis. An asymmetrical model derived from Bouc-
Wen differential equation is employed to describe hys-
teretic behavior of vibration engineering. A practical
polynomial expression for hysteretic restoring force
is deduced to be substituted into standard equation
of the system, assuming that the non-linearity of the
restoring force is weak. An asymptotic method, which
combines Krylov-Bogolyubov-Mitropolsky (KBM)
method with harmonic balance (HB) method, is ap-
plied to analyze steady-state responses of the asym-
metrical hysteretic system subjected to harmonic exci-
tation. Dynamic responses, such as the restoring force
time histories and frequency responses of the sys-
tem for the ?rst order approximate, are obtained. Fur-
thermore, numerical solution obtained using Runge-
Kutta method as well as results of experiments (as-
phalt compaction on the Beijing-Fuzhou highway) are
compared with the asymptotic solution. These results
investigated that asymmetrical hysteretic model and
the methods applied in this paper are quite appropriate
for engineering applications.Keywords Vibratory compaction · Asymmetrical
hysteresis · Bouc-Wen model · Asymptotic method ·
Dynamic analysis 11322
1 Introduction
Many mechanical and structural systems under severe
dynamic loading usually become inelastic and exhibit
nonlinear hysteretic behavior [1, 2]. Hysteresis depicts
the nature of heredity and memory in the inelastic sys-
tem, that is, the restoring force depends not only on
instantaneous deformation, but also on the past history
of the deformation. Therefore, hysteretic systems may
display complex dynamic behaviors and energy dissi-
pation properties. Investigating the vibration charac- 本文来源:http://www.mamitama.com/a/www.qhswdx.com/

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teristics of such systems is of great importance to en-
gineering applications, such as building structures [3],
vibrating fuel rod [4] and ER damper for vehicles [5].
In the past decades, various nonlinear hysteretic
models have been developed for modeling the hered-
itary nature of the restoring force of inelastic sys-
tems. Caughey [6] put forward a bilinear model to
analyze a single-degree-of-freedom (S.D.O.F.) hys-
teretic system. Then piecewise-linear model [7–9],
degrading piecewise-linear model [10], and binon-
linear model [11] were proposed to describe this non-
linear hysteretic nature. One of the most commonly
used hystereticmodels is Bouc-Wen differentialmodel
[12, 13]. This versatile model represents a wide vari-can be well described, such as softening or hardening,
narrow or wide loops. For example, when the value of
¯ β increases, the width of the hysteretic loop, i.e., the
dissipation energy of the hysteretic model system, be-
comes large.
Because the restoring force Z(t) is not expressed
by the polynomial of the displacement x(t) in (2), ap-
proximate analytical methods cannot be applied di-
rectly to (1). By setting n = 1, the equation of the
restoring force Z(t) is turned into:
˙ Z(t) = A˙ x(t)− ¯ β|˙ x(t)|Z(t) −¯ γ ˙ x(t)|Z(t)|. (3)
Considering the exponential of hysteretic restoring
force, (3) is integrated and pided into four intervals.
The hysteretic force Z(t) is depicted as following:where Bi and Di (i = 1, 2, 3, 4) are constants of in-
tegration. Zi (t) (i = 1, 2, 3, 4) represent the restoring
force for intervals (1)to(4) respectively as shown in
Fig. 2.
Assuming that the non-linearity of the restoring
force is weak, a small positive scaling parameter ε is
introduced, and the parameters ¯ β and ¯ γ which control 振动压实系统英文文献和中文翻译:重庆时时彩的规律/a/fanyi/20170709/10688.html
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