In situ determination of loss and coupling loss factors by the power injection method

1980 ◽  
Vol 70 (2) ◽  
pp. 187-204 ◽  
Author(s):  
D.A. Bies ◽  
S. Hamid
Keyword(s):  
Coupling Loss ◽  
Injection Method ◽  
Power Injection ◽  
Loss Factors

Coupling Loss Factors and Coupling Damping for Flanged Cylindrical Shells

1991 ◽  
Author(s):  
P. R. Keswick ◽  
M. P. Norton
Keyword(s):  
Loss Factor ◽  
Cylindrical Shells ◽  
Coupled Systems ◽  
Flange Joint ◽  
Coupling Loss ◽  
Theoretical Evaluation ◽  
Injection Method ◽  
Power Injection ◽  
Coupling Loss Factor ◽  
Loss Factors

Abstract This paper reports on an investigation into an experimental and theoretical evaluation of coupling loss factors and the experimental evaluation of coupling damping for statistical energy analysis of flanged cylindrical shells. It includes the following. 1. An evaluation of the power injection method and the steady state energy method for determining the coupling loss factors of conservative and non-conservatively coupled cylindrical shells. The investigation also establishes if it is necessary to use post processing or additional damping to the subsystems to obtain meaningful loss and coupling loss factors from the power injection method. 2. Establishment of a procedure for measuring coupling damping using the in-situ loss factors measured from the power injection method for non-conservatively coupled systems. The coupling damping estimates are measured for the same non-conservatively coupled cylindrical shell as used for the coupling loss factor experiments. 3. Usage of an elastic wave propagation analysis to obtain theoretical estimates of the coupling loss factors for cylindrical shells connected by a solid flange joint using the Fliigge stress equations for cylindrical shells. The flange joint arrangement is modelled as a ring connecting the two shell halves, where the Love equations are used to develop the in-plane and out-of-plane ring forces and moment. The coupling loss factor is calculated from the power transmitted across the joint and from the stored energy on the incident side.

Experimental Determination of Vibration Parameters Required in the Statistical Energy Analysis Method

1983 ◽  
Vol 105 (3) ◽  
pp. 337-344 ◽  
Author(s):  
B. L. Clarkson ◽  
R. J. Pope
Keyword(s):  
Experimental Determination ◽  
Analysis Method ◽  
Coupling Loss ◽  
Structural Components ◽  
Indirect Methods ◽  
Vibration Parameters ◽  
Theoretical Results ◽  
Dissipation Loss ◽  
Loss Factors

In the high frequency range of vibration the Statistical Energy Method provides one of the most convenient ways of estimating vibration levels in structural components. The dynamic characteristics of the structure are described in terms of the modal densities, dissipation loss factors and coupling loss factors of the component parts. Theoretical and semiempirical results are available for some typical components. This paper describes the development of indirect methods for the experimental determination of these three parameters. Where theoretical results are available the experimental results show reasonable agreement. The results of tests on a range of components are described.

Determination of Non-Conservative Coupling Loss Factors Between Rotating Machinery Components

1991 ◽  
Author(s):  
J. M. Cuschieri ◽  
J. C. Sun ◽  
F. Journeau
Keyword(s):  
Experimental Results ◽  
Coupling Loss ◽  
Analysis Model ◽  
Impedance Function ◽  
Dissipation Term ◽  
Interface Characteristics ◽  
Film Interface ◽  
Good Agreement ◽  
Loss Factors

Abstract An expression for calculating the coupling loss factors between non-conservatively coupled substructures is derived based on the characteristics of the coupled substructures and the interface medium. The expressions consists of point mobility functions evaluated on the substructures near or at the junctions and a joint impedance function which represents the interface characteristics. The point mobility functions can be obtained analytically, for simple structures, or experimentally. The joint impedance is modeled by a dissipative stiffness element. The derived expressions for the coupling loss factors simplify to the well known expressions for conservative coupling when the dissipation term tends to zero. This approach is used to estimate the coupling loss factor between a shaft and a bearing liner with an oil film interface. The estimated results for the coupling loss factors are compared to experimental results obtained from a statistical energy analysis model. The estimated results and the experimental results show good agreement which verifies the approach used for the determination of the non-conservative coupling loss factors.

INDIREKTE PAPIERCHROMATOGRAPHISCHE METHODE ZUR BESTIMMUNG DER HARNOESTROGENE

1961 ◽  
Vol 38 (4) ◽  
pp. 545-562 ◽  
Author(s):  
L. Kecskés ◽  
F. Mutschler ◽  
I. Glós ◽  
E. Thán ◽  
I. Farkas ◽  
...  
Keyword(s):  
Pregnant Women ◽  
Granulosa Cell ◽  
Iron Content ◽  
List Type ◽  
Granulosa Cell Tumour ◽  
Hydrolysis Of ◽  
Phenol Fraction ◽  
Qualitative Determination

ABSTRACT 1. An indirect paperchromatographic method is described for separating urinary oestrogens; this consists of the following steps: acidic hydrolysis, extraction with ether, dissociation of phenol-fractions with partition between the solvents. Previous purification of phenol fraction with the aid of paperchromatography. The elution of oestrogen containing fractions is followed by acetylation. Oestrogen acetate is isolated by re-chromatography. The chromatogram was developed after hydrolysis of the oestrogens 'in situ' on the paper. The quantity of oestrogens was determined indirectly, by means of an iron-reaction, after the elution of the iron content of the oestrogen spot, which was developed by the Jellinek-reaction. 2. The method described above is satisfactory for determining urinary oestrogen, 17β-oestradiol and oestriol, but could include 16-epioestriol and other oestrogenic metabolites. 3. The sensitivity of the method is 1.3–1.6 μg/24 hours. 4. The quantitative and qualitative determination of urinary oestrogens with the above mentioned method was performed in 50 pregnant and 9 non pregnant women, and also in 2 patients with granulosa cell tumour.

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