An experimental investigation into the insertion loss from subscale acoustic enclosures with geometric imperfections

2017 ◽  
Vol 141 (5) ◽  
pp. 3576-3577 ◽  
Author(s):  
Christopher Beale ◽  
Murat Inalpolat ◽  
Christopher Niezrecki ◽  
David J. Willis
Keyword(s):  
Experimental Investigation ◽  
Insertion Loss ◽  
Geometric Imperfections ◽  
Acoustic Enclosures

Appraisal of Allowable Loads by Simplified Rules

1986 ◽  
Vol 108 (2) ◽  
pp. 131-137
Author(s):  
D. Moulin
Keyword(s):  
Experimental Investigation ◽  
Plastic Region ◽  
Thin Structures ◽  
Geometric Imperfections ◽  
Buckling Behavior ◽  
Simplified Method ◽  
Post Buckling ◽  
Initial Geometric Imperfections ◽  
Fast Breeder Reactors ◽  
Breeder Reactors

This paper presents a simplified method to analyze the buckling of thin structures like those of Liquid Metal Fast Breeder Reactors (LMFBR). The method is very similar to those used for the buckling of beams and columns with initial geometric imperfections, buckling in the plastic region. Special attention is paid to the strain hardening of material involved and to possible unstable post-buckling behavior. The analytical method uses elastic calculations and diagrams that account for various initial geometric defects. An application of the method is given. A comparison is made with an experimental investigation concerning a representative LMFBR component.

scholarly journals Wideband Waveguide-to-Microstrip Transition for mm-Wave Applications

2019 ◽  
Vol 22 (5) ◽  
pp. 17-32
Author(s):  
Andrey V. Mozharovskiy ◽  
Oleg V. Soykin ◽  
Aleksey A. Artemenko ◽  
Roman O. Maslennikov ◽  
Irina B. Vendik
Keyword(s):  
Experimental Investigation ◽  
Millimeter Wave ◽  
Insertion Loss ◽  
Communication Systems ◽  
60 Ghz ◽  
Feeding System ◽  
Frequency Range ◽  
Low Loss ◽  
Passive Components ◽  
Full Wave

Introduction. Increased data rate in modern communication systems can be achieved by raising the operational frequency to millimeter wave range where wide transmission bands are available. In millimeter wave communication systems, the passive components of the antenna feeding system, which are based on hollow metal waveguides, and active elements of the radiofrequency circuit, which have an interface constructed on planar printed circuit boards (PCB) are interconnected using waveguide-to-microstrip transition.Aim. To design and investigate a high-performance wideband and low loss waveguide-to-microstrip transition dedicated to the 60 GHz frequency range applications that can provide effective transmission of signals between the active components of the radiofrequency circuit and the passive components of the antenna feeding systemMaterials and methods. Full-wave electromagnetic simulations in the CST Microwave Studio software were used to estimate the impact of the substrate material and metal foil on the characteristics of printed structures and to calculate the waveguide-to-microstrip transition characteristics. The results were confirmed via experimental investigation of fabricated wideband transition samples using a vector network analyzer Results. The probe-type transition consist of a PCB fixed between a standard WR-15 waveguide and a back-short with a simple structure and the same cross-section. The proposed transition also includes two through-holes on the PCB in the center of the transition area on either side of the probe. A significant part of the lossy PCB dielectric is removed from that area, thus providing wideband and low-loss performance of the transition without any additional matching elements. The design of the transition was adapted for implementation on the PCBs made of two popular dielectric materials RO4350B and RT/Duroid 5880. The results of full-wave simulation and experimental investigation of the designed waveguide to microstrip transition are presented. The transmission bandwidth for reflection coefficient S11 < –10 dB is in excess of 50…70 GHz. The measured insertion loss for a single transition is 0.4 and 0.7 dB relatively for transitions based on RO4350B and RT/Duroid 5880.Conclusion. The proposed method of insertion loss reduction in the waveguide-to-microstrip transition provides effective operation due to reduction of the dielectric substrate portion in the transition region for various high-frequency PCB materials. The designed waveguide-to -microstrip transition can be considered as an effective solution for interconnection between the waveguide and microstrip elements of the various millimeter-wave devices dedicated for the 60 GHz frequency range applications.

An experimental investigation of the effects of imperfections on the strength of steel box girders

1988 ◽  
Vol 15 (3) ◽  
pp. 443-449 ◽  
Author(s):  
R. M. Korol ◽  
E. G. Thimmhardy ◽  
M.S. Cheung
Keyword(s):  
Experimental Investigation ◽  
Residual Stresses ◽  
Carrying Capacity ◽  
Scale Model ◽  
Bridge Structure ◽  
Box Girders ◽  
Box Girder ◽  
Geometric Imperfections ◽  
Longitudinal Stiffeners ◽  
The One

As part of a major study, an experimental box girder having nominally identical cantilever sections was constructed to model the geometry of a pier girder of the Hunt Club–Rideau Bridge structure in Ottawa. The one-fourth scale model did not, however, replicate the varying depth of the prototype. The objective was to determine whether a deliberate reduction in the gross heat input for welds attaching longitudinal stiffeners to the flange plates for one end of the girder (and hence would incur reduced plate distortions and residual stresses) could augment the carrying capacity of a statically loaded box girder. In fact, the results from the two tests are such as to suggest that inward bent transverse stiffeners may account for a greater reduction in strength than do the imperfections of local plate panels of compression flanges. Key words: box girders, bridges, experiments, geometric imperfections, residual stresses, strength, structural steel.

The Folding of Triangulated Cylinders, Part III: Experiments

1996 ◽  
Vol 63 (1) ◽  
pp. 77-83 ◽  
Author(s):  
S. D. Guest ◽  
S. Pellegrino
Keyword(s):  
Experimental Investigation ◽  
Computational Models ◽  
Computational Simulation ◽  
Geometric Imperfections ◽  
Cylindrical Structure ◽  
Truss Model

This paper describes an experimental investigation of a type of foldable cylindrical structure, first presented in two earlier papers. Three cylinders of this type were designed and manufactured, and were then tested to find the force required to fold them. The results from these tests show some discrepancies with an earlier computational simulation, which was based on a pin-jointed truss model of the cylinders. Possible explanations for these discrepancies are explored, and are then verified by new simulations using computational models that include the effect of hinge stiffness, and the effect of geometric imperfections.

Numerical and Experimental Investigation of the Acoustic and Flow Performance of Intake Systems

2002 ◽  
Vol 124 (3) ◽  
pp. 334-339 ◽  
Author(s):  
P. A. Rusch ◽  
A. K. Dhingra
Keyword(s):  
Fluid Dynamics ◽  
Experimental Investigation ◽  
Insertion Loss ◽  
Bench Test ◽  
Experimental Measurements ◽  
Test Results ◽  
One Dimensional ◽  
Intake System ◽  
Duct Systems ◽  
Cylindrical Duct

This paper investigates the acoustic and flow performance of an intake system using numerical and experimental techniques. The acoustic and flow performances are characterized by computing the Insertion Loss (IL) and the loss coefficient (LC) respectively. An indirect BEM formulation is used to predict the IL. The LC is computed by solving a one-dimensional fluid dynamics problem. For four simple cylindrical duct systems, numerical results for IL and LC are compared with experimental measurements. Finally, the acoustic and flow performance of an actual motorcycle intake is predicted and the results are compared to bench test results.

Do moods and expectancies have unique or interactive effects?: An experimental investigation

2014 ◽  
Author(s):  
Shane Close ◽  
Victoria Adkins ◽  
Kandice Perry ◽  
Katheryn Eckles ◽  
Jill Brown ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Interactive Effects
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