Reflected sound field by stage floors in the concert halls: Theoretical model analysis

1998 ◽  
Vol 103 (5) ◽  
pp. 2749-2749 ◽  
Author(s):  
Shinsuke Nakanishi ◽  
Kimihiro Sakagami ◽  
Masayuki Morimoto
Keyword(s):  
Theoretical Model ◽  
Sound Field ◽  
Model Analysis ◽  
Concert Halls

Modelling of Scattering from Balcony Fronts

2002 ◽  
Vol 9 (3) ◽  
pp. 219-231
Author(s):  
T. M. Chan ◽  
W. M. To
Keyword(s):  
Computer Simulation ◽  
Ray Tracing ◽  
Diffuse Reflection ◽  
Sound Field ◽  
Direct Wave ◽  
Practice Experience ◽  
Concert Halls ◽  
Distinguished Group ◽  
Opera Houses

Balconies are normally used in large auditoria such as concert halls or opera houses, to increase seating capacity or to give better view for a distinguished group of the audience. When ray-tracing based computer models are applied to study the acoustical quality of these auditoria, the alteration of the sound field due to balcony fronts is normally unobservable, because of the relative small size of the balcony fronts in the auditorium. Furthermore, most diffuse reflection ray-tracing methods are not based on direct wave acoustics but on an approximation of the scattering effect. In practice, experience shows that balcony fronts give additional warmth to music. This effect is more prominent when singers perform in traditional horseshoe shaped opera houses with multi-levels balconies. This paper describes modelling of scattering from balcony fronts using a theoretical wave approach, in which the incident wave front is not plane but spherical. A computer simulation illustrates the scattering of sound that takes place when the wavefront impinges on the surface of the balcony fronts.

Research on Dynamic Design Method Based on Measuring Information for Printing Press

2010 ◽  
Vol 174 ◽  
pp. 290-294
Author(s):  
Yi Ming Wang ◽  
Bang She Chen ◽  
Yan Li ◽  
Shao Hua Zhang
Keyword(s):  
Theoretical Model ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Model Analysis ◽  
Printing Press ◽  
Vibration Measurement ◽  
Dynamic Design ◽  
Analysis Experiment ◽  
Printing Machine

Printing machinery’s reliability is one of the most important index parameter and good dynamic characteristics are essential for high speed printing press. The dynamic characteristic is predictable for printing machine with dynamic design. With the complexity of printing technique and printing machine, information, such as load on components is lack, leading to the difficulty of dynamic model solving and further more the dynamic parameters needs to be verified. Firstly, according to the dynamic design method, a dynamic design process based on measuring information for printing machine was put forward. Secondly, on the basis of principle and structure analysis to typical printing machine, dynamic characteristics measurement item and method was determined. With a wallboard of a two-color offset press acting as an example, the utilizing method was illustrated through dynamic modeling, theoretical model analysis, experiment model analysis based on vibration measurement and comparing the theoretical and experimental results. Finally, a Dynamic Design Assistant Platform based Vibration Measurement for Printing Machine was developed and had been used in 10 kinds of printing machine measurement and analysis. The conclusion shows that the tolerance of the theoretical model analysis results and experiment results is allowed. A new approach for new printing machine design and optimal design for existed printing machine is given.

Fatigue investigation of a railway truss bridge

1984 ◽  
Vol 11 (3) ◽  
pp. 625-631 ◽  
Author(s):  
Z. L. Szeliski ◽  
I. A. Elkholy
Keyword(s):  
Theoretical Model ◽  
Sample Size ◽  
Fatigue Damage ◽  
Field Measurement ◽  
High Strength ◽  
Traffic Analysis ◽  
Model Analysis ◽  
Remaining Life ◽  
Repetitive Loading ◽  
Truss Bridge

The advent of unit trains and high gross tonnage has made it necessary to evaluate the effect of repetitive loading on bridges. A description of a fatigue investigation of a 35.7 m (117 ft) railway through truss span is presented. The study consisted of (1) field measurement; (2) theoretical model analysis; (3) traffic analysis; (4) estimate of fatigue damage; (5) evaluation of fatigue detail category; (6) estimate of remaining life; and (7) action required. The effect of car sequence in trains, sample size, flat wheels, and impact on level of stresses is examined. As a result of the study, the trusses were retrofitted by removing rivets, reaming holes, and placing high-strength bolts.

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