Analysis of acoustic characteristics in the vocal tract with inhomogeneous wall impedance using a three-dimensional fem model

1994 ◽  
Vol 77 (10) ◽  
pp. 27-36
Author(s):  
Hiroki Matsuzaki ◽  
Tohru Hirohku ◽  
Nobuhiro Miki ◽  
Nobuo Nagai
Keyword(s):  
Vocal Tract ◽  
Three Dimensional ◽  
Fem Model ◽  
Acoustic Characteristics

Optimization of the Wrist Pin End of an Automobile Engine Connecting Rod With an Interference Fit

1990 ◽  
Vol 112 (3) ◽  
pp. 406-412 ◽  
Author(s):  
Vijay Sarihan ◽  
Ji Oh Song
Keyword(s):  
Finite Element ◽  
Optimum Design ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Design Strategy ◽  
Structural Components ◽  
Connecting Rod ◽  
Fem Model ◽  
Automobile Engine ◽  
Interference Fit

Current design procedures for complicated three-dimensional structural components with component interactions may not necessarily result in optimum designs. The wrist pin end design of the connecting rod with an interference fit is governed by the stress singularity in the region where the wrist pin breaks contact with the connecting rod. Similar problems occur in a wide variety of structural components which involve interference fits. For a better understanding of the problems associated with obtaining optimum designs for this important class of structural interaction only the design problems associated with the wrist pin end of the rod are addressed in this study. This paper demonstrates a procedure for designing a functional and minimum weight wrist pin end of an automobile engine connecting rod with an interference fit wrist pin. Current procedures for Finite Element Method (FEM) model generation in complicated three-dimensional components are very time consuming especially in the presence of stress singularities. Furthermore the iterative nature of the design process makes the process of developing an optimum design very expensive. This design procedure uses a generic modeler to generate the FEM model based on the values of the design variables. It uses the NASTRAN finite element program for structural analysis. A stress concentration factor approach is used to obtain realistic stresses in the region of the stress singularity. For optimization, the approximate optimization strategy in the COPES/CONMIN program is used to generate an approximate design surface, determine the design sensitivities for constrained function minimization and obtain the optimum design. This proposed design strategy is fully automated and requires only an initial design to generate the optimum design. It does not require analysis code modifications to compute the design sensitivities and requires very few costly NASTRAN analyses. The connecting rod design problem was solved as an eight design variable problem with five constraints. A weight reduction of nearly 27 percent was achieved over an existing design and required only thirteen NASTRAN analyses. It is felt that this design strategy can be effectively used in an engineering environment to generate optimum designs of complicated three-dimensional components.

scholarly journals EFFICIENT ACOUSTIC COMPOSITE PANELS BASED ON GRAPHITE

2021 ◽  
Vol 6 (4) ◽  
pp. 82-90
Author(s):  
E. Fanina
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Sound Field ◽  
Fire Retardant ◽  
Pyramidal Cells ◽  
Sound Insulation ◽  
Composite Panels ◽  
Thin Membrane ◽  
Reverberation Time ◽  
Acoustic Characteristics

A set of experimental studies is carried out to determine the acoustic characteristics of three-dimensional panels of fixed thickness made of carbon-based composite material installed in the opening between the reverberation chambers. Sound insulation indices are determined when they are excited by a diffuse sound field in wide frequency ranges. The reverberation time in model chambers with different partition configurations is calculated. The optimal configuration of the partition with pyramidal cells to reduce the reverberation time in the rooms is determined. The use of graphite in the form of thin membrane applied to various surfaces can significantly reduce the sound pressure levels in the room and increase the sound insulation indices of air noise. In addition to thin membrane, graphite can be used as an additive in composite materials for sound insulation purposes. It is shown that the characteristics of such panels are quite universal. The measured acoustic characteristics of composite panels are compared with similar characteristics of traditional materials. It is determined that the composition belongs to the I group of fire-retardant efficiency and can be recommended for use as a fire-retardant material. The developed acoustic material is an effective absorbing agent that solves problems in architectural acoustics, echo cancellation in construction and architecture. Similar to metamaterials, natural and artificial graphites allow to solve these problems with small volumes and masses using simple and inexpensive technologies.

Speech-Based Clinical Diagnostic Systems

2011 ◽  
pp. 1439-1446
Author(s):  
Jesús Bernardino Alonso Hernández ◽  
Patricia Henríquez Rodríguez
Keyword(s):  
Speech Signal ◽  
Vocal Tract ◽  
Subjective Evaluation ◽  
Voice Quality ◽  
Quality Measurement ◽  
Vocal Folds ◽  
Speech Quality ◽  
Diagnostic Systems ◽  
Acoustic Characteristics ◽  
Clinical Measurements

It is possible to implement help systems for diagnosis oriented to the evaluation of the fonator system using speech signal, by means of techniques based on expert systems. The application of these techniques allows the early detection of alterations in the fonator system or the temporary evaluation of patients with certain treatment, to mention some examples. The procedure of measuring the voice quality of a speaker from a digital recording consists of quantifying different acoustic characteristics of speech, which makes it possible to compare it with certain reference patterns, identified previously by a “clinical expert”. A speech acoustic quality measurement based on an auditory assessment is very hard to assess as a comparative reference amongst different voices and different human experts carrying out the assessment or evaluation. In the current bibliography, some attempts have been made to obtain objective measures of speech quality by means of multidimensional clinical measurements based on auditory methods. Well-known examples are: GRBAS scale from Japon (Hirano, M.,1981) and its extension developed and applied in Europe (Dejonckere, P. H. Remacle, M. Fresnel-Elbaz, E. Woisard, V. Crevier- Buchman, L. Millet, B.,1996), a set of perceptual and acoustic characteristics in Sweden (Hammarberg, B. & Gauffin, J., 1995), a set of phonetics characteristics with added information about the excitement of the vocal tract. The aim of these (quality speech measurements) procedures is to obtain an objective measurement from a subjective evaluation. There exist different works in which objective measurements of speech quality obtained from a recording are proposed (Alonso J. B.,2006), (Boyanov, B & Hadjitodorov, S., 1997),(Hansen, J.H.L., Gavidia-Ceballos, L. & Kaiser, J.F., 1998),(Stefan Hadjitodorov & Petar Mitev, 2002),(Michaelis D.; Frohlich M. & Strube H. W. ,1998),(Boyanov B., Doskov D., Mitev P., Hadjitodorov S. & Teston B.,2000),(Godino-Llorente, J.I.; Aguilera-Navarro, S. & Gomez-Vilda, P. , 2000). In these works a voiced sustained sound (usually a vowel) is recorded and then used to compute speech quality measurements. The utilization of a voiced sustained sound is due to the fact that during the production of this kind of sound, the speech system uses almost all its mechanisms (glottal flow of constant air, vocal folds vibration in a continuous way, …), enabling us to detect any anomaly in these mechanisms. In these works different sets of measurements are suggested in order to quantify speech quality objectively. In all these works one important fact is revealed; it is necessary to obtain different measurements of the speech signal in order to compile the different aspects of acoustic characteristics of the speech signal.

Three-Dimensional FEM Simulation of the Ship-Bridge Collision

2013 ◽  
Vol 405-408 ◽  
pp. 3243-3247
Author(s):  
Wei Su ◽  
Ying Sun ◽  
Shi Qing Huang ◽  
Ren Huai Liu
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Reference Values ◽  
Large Scale ◽  
Three Dimensional ◽  
Fem Simulation ◽  
Structural Safety ◽  
Fem Model ◽  
Finite Element Software

In this paper, the structural safety of the Niuwan Bridge subjected to vessel collision is investigated by the large-scale commercial finite element software ANSYS. A whole FEM model is built and a reasonable analysis and illustration for taking the value of vessel-collision forces is presented. Additionally, under the premise of reasonable simulation of the boundary conditions, the effects of the support abutments, the prestress and the carloads are considered. The analysis results have certain reference values for the anti-collision and reinforcement of bridges.

Three-Dimensional Finite Element Prediction of Machining-Induced Stresses

Manufacturing ◽  
2003 ◽  
Author(s):  
T. D. Marusich ◽  
S. Usui ◽  
R. J. McDaniel
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Metal Cutting ◽  
Three Dimensional ◽  
Constitutive Models ◽  
Fatigue Loading ◽  
Cyclic Fatigue ◽  
Fem Model ◽  
Machined Parts ◽  
Three Dimensional Finite Element

Controlling residual stress in machined workpiece surfaces is necessary in situations where service requirements subject structural members to cyclic fatigue loading. It is desirable to have a predictive capability when attempting to optimize machined parts for cost while taking into account residual stress considerations. One such method of machining modeling is application of the finite element method (FEM). A three-dimensional FEM model is presented which includes fully adaptive unstructured mesh generation, tight thermo-mechanically coupling, deformable tool-chip-workpiece contact, interfacial heat transfer across the tool-chip boundary, momentum effects at high speeds and constitutive models appropriate for high strain rate, finite deformation analyses. The FEM model is applied to nose turning operations with stationary tools. To substantiate the efficacy of numerical and constitutive formulations used, metal cutting tests are performed, residual stress profiles collected, and validation comparison is made.

Extraction of vocal tract area function from three‐dimensional magnetic resonance images using digital waveguide mesh

2008 ◽  
Vol 123 (5) ◽  
pp. 3736-3736
Author(s):  
Kenji Inoue ◽  
Hironori Takemoto ◽  
Tatsuya Kitamura ◽  
Shinobu Masaki ◽  
Hirotake Nakashima
Keyword(s):  
Magnetic Resonance ◽  
Vocal Tract ◽  
Three Dimensional ◽  
Magnetic Resonance Images ◽  
Area Function ◽  
Digital Waveguide Mesh ◽  
Digital Waveguide
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