scholarly journals Optimization of Classical Hydraulic Engine Mounts Based on RMS Method

2005 ◽  
Vol 12 (2) ◽  
pp. 119-147 ◽  
Author(s):  
J. Christopherson ◽  
G. Nakhaie Jazar
Keyword(s):  
Time Domain ◽  
Relative Displacement ◽  
Response Functions ◽  
Optimal Parameters ◽  
Absolute Acceleration ◽  
Engine Mounts ◽  
Engine Mount ◽  
The Absolute ◽  
Time Domain Response ◽  
The Time Domain

Based on RMS averaging of the frequency response functions of the absolute acceleration and relative displacement transmissibility, optimal parameters describing the hydraulic engine mount are determined to explain the internal mount geometry. More specifically, it is shown that a line of minima exists to define a relationship between the absolute acceleration and relative displacement transmissibility of a sprung mass using a hydraulic mount as a means of suspension. This line of minima is used to determine several optimal systems developed on the basis of different clearance requirements, hence different relative displacement requirements, and compare them by means of their respective acceleration and displacement transmissibility functions. In addition, the transient response of the mount to a step input is also investigated to show the effects of the optimization upon the time domain response of the hydraulic mount.

Simulation of Engine Vibration on Nonlinear Hydraulic Engine Mounts

2005 ◽  
Author(s):  
A. R. Ohadi ◽  
G. Maghsoodi
Keyword(s):  
Equations Of Motion ◽  
Low Frequency ◽  
Governing Equations ◽  
Engine Mounts ◽  
Engine Vibration ◽  
Engine Mount ◽  
Rotational Motions ◽  
The Time Domain ◽  
Nonlinear Equations Of Motion ◽  
Four Cylinders

In this paper, vibration behavior of engine on nonlinear hydraulic engine mount including inertia track and decoupler is studied. In this regard, after introducing the nonlinear factors of this mount (i.e. inertia and decoupler resistances in turbulent region), the vibration governing equations of engine on one hydraulic engine mount are solved and the effect of nonlinearity is investigated. In order to have a comparison between rubber and hydraulic engine mounts, a 6 degree of freedom four cylinders V-shaped engine under inertia and balancing masses forces and torques is considered. By solving the time domain nonlinear equations of motion of engine on three inclined mounts, translational and rotational motions of engines body are obtained for different engine speeds. Transmitted base forces are also determined for both types of engine mount. Comparison of rubber and hydraulic mounts indicates the efficiency of hydraulic one in low frequency region.

A compensation method for membrane-covered (Clark) electrodes

1988 ◽  
Vol 65 (3) ◽  
pp. 1430-1435 ◽  
Author(s):  
S. A. Barton ◽  
C. E. Hahn ◽  
A. M. Black
Keyword(s):  
Infinite Series ◽  
Direct Current ◽  
Time Domain ◽  
Blood Gases ◽  
Time Parameter ◽  
Response Functions ◽  
Speed Of Response ◽  
Pulsed Mode ◽  
Covered Electrodes ◽  
The Time Domain

Membrane-covered electrodes (Clark electrodes) are widely used for monitoring blood gases, particularly PO2. A method of compensating for the inherently limited speed of response of Clark electrodes is presented. The theoretical response in the time domain is related to that in the frequency domain, and the latter is deduced from measurement of the former. Although the response functions are both infinite series, both responses are nevertheless completely defined by a single time parameter Te characteristic of the electrode under given measurement conditions. Practical verification was performed using electrodes in the double-pulsed mode, but the theory is applicable equally to direct-current-polarized and simply pulsed electrodes.

scholarly journals Time-Domain Substructure Transient Vibration Transfer Path Analysis Based on Time-Varying Frequency Response Functions under Operational Excitations

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Rong He ◽  
Hong Zhou
Keyword(s):  
Path Analysis ◽  
Frequency Response ◽  
Time Domain ◽  
Time Varying ◽  
Response Functions ◽  
Transient Vibration ◽  
Transfer Path ◽  
Time Varying Systems ◽  
Transfer Path Analysis ◽  
The Time Domain

The time-domain substructure inverse matrix method has become a popular method to detect and diagnose problems regarding vehicle noise, vibration, and harshness, especially for those impulse excitations caused by roads. However, owning to its reliance on frequency response functions (FRFs), the approach is effective only for time-invariable linear or weak nonlinear systems. This limitation prevents this method from being applied to a typical vehicle suspension substructure, which shows different nonlinear characteristics under different wheel transient loads. In this study, operational excitation was considered as a key factor and applied to calculate dynamic time-varying FRFs to perform accurate time-domain transient vibration transfer path analysis (TPA). The core idea of this novel method is to divide whole coupled substructural relationships into two parts: one involved time-invariable components; normal FRFs could be obtained through tests directly. The other involved numerical computations of the time-domain operational loads matrix and FRFs matrix in static conditions. This method focused on determining dynamic FRFs affected by operational loads, especially the severe transient ones; these loads are difficult to be considered in other classical TPA approaches, such as operational path analysis with exogenous inputs (OPAX) and operational transfer path analysis (OTPA). Experimental results showed that this new approach could overcome the limitations of the traditional time-domain substructure TPA in terms of its strict requirements within time-invariable systems. This is because in the new method, time-varying FRFs were calculated and used, which could make the FRFs at the system level directly adapt to time-varying systems from time to time. In summary, the modified method extends TPA objects studied in time-invariable systems to time-varying systems and, thus, makes a methodology and application innovation compared to traditional the time-domain substructure TPA.

Improving the time domain response of fractional order digital differentiators by windowing

2015 ◽  
Vol 107 ◽  
pp. 282-289 ◽  
Author(s):  
Chengyan Peng ◽  
Xiaochuan Ma ◽  
Geping Lin ◽  
Min Wang
Keyword(s):  
Fractional Order ◽  
Time Domain ◽  
Time Domain Response ◽  
The Time Domain

A Novel Technique for Frequency and Time Optimization of Automotive Engine Mount Parameters

2006 ◽  
Author(s):  
S. Arzanpour ◽  
N. Eslaminasab ◽  
B. Shubert ◽  
A. Narimani ◽  
M. F. Golnaraghi
Keyword(s):  
Frequency Domain ◽  
Relative Displacement ◽  
Vehicle Body ◽  
Automotive Engine ◽  
Response Characteristics ◽  
Novel Approach ◽  
Engine Mount ◽  
Optimal Values ◽  
The Time Domain ◽  
Forced Excitation

In this paper, we examine a linear one degree of freedom engine mount to obtain optimum mount parameters in a passive configuration. An engine mount is a device that may be used to isolate vehicle body from the engine vibrations - forced excitation, while minimizing the effects of road-induced disturbances on the engine - base excitation. The linearity of the system allows us to analyze the frequency and time response characteristics in both excitation cases analytically. Optimal damping and stiffness values for the isolator are obtained by minimizing certain cost functions in the frequency and time domains, respectively. In the frequency domain the cost function is based on the root mean square (RMS) of the absolute acceleration and relative displacement in the frequency domain, and in the time domain it is based on the transmitted acceleration and displacement. The time and frequency responses of the isolator are optimized by varying the stiffness and damping ratios for both base and forced excitation cases. These optimal values are obtained, and the results are verified numerically. In this case, although the mathematical model is linear, it is interesting to note that the time and frequency optimal values are not the same. As a result, this exercise shows that no passive-mount is adequate to perfectly deal with all application specs and isolation criteria. In this paper, a novel approach is suggested to select the mount parameters for various passive or active configurations.

scholarly journals Scattering of an Impact Wave by a Crack in a Composite Plate

1992 ◽  
Vol 59 (3) ◽  
pp. 596-603 ◽  
Author(s):  
S. K. Datta ◽  
T. H. Ju ◽  
A. H. Shah
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Impact Load ◽  
Near Field ◽  
Boundary Integral ◽  
Transition Elements ◽  
Element Discretization ◽  
Crack Tips ◽  
Time Domain Response ◽  
The Time Domain

The surface responses due to impact load on an infinite uniaxial graphite/epoxy plate containing a horizontal crack is investigated both in time and frequency domain by using a hybrid method combining the finite element discretization of the near-field with boundary integral representation of the field outside a contour completely enclosing the crack. This combined method leads to a set of linear unsymmetric complex matrix equations, which are solved to obtain the response in the frequency domain by biconjugate gradient method. The time-domain response is then obtained by using an FFT. In order to capture the time-domain characteristics accurately, high-order finite elements have been used. Also, both the six-node singular elements and eight-node transition elements are used around the crack tips to model the crack-tip singularity. From the numerical results for surface responses it seems possible to clearly identify both the depth and length of this crack.

Improved analysis of the time domain response of scanning force microscope cantilevers

2000 ◽  
Vol 88 (12) ◽  
pp. 7321-7327 ◽  
Author(s):  
Brian A. Todd ◽  
Steven J. Eppell ◽  
Fredy R. Zypman
Keyword(s):  
Time Domain ◽  
Scanning Force Microscope ◽  
Scanning Force ◽  
Time Domain Response ◽  
The Time Domain
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