A Numerical Method for Noise Optimization of Engine Structures

Milsted, M.G.; Zhang, T; Hall, R.A.

doi:10.1243/pime_proc_1993_207_171_02

Cited by 13 publications

(16 citation statements)

References 3 publications

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“…Indeed, this 'one-way' coupling is exploited in the proposed strategy in this work. Lamancusa (1993) discusses several choices of design variables and objective functions that have been used, and concludes that the choice of acoustic power as an objective function produces the most consistently improved designs; examples of works where sound power is optimized are Belegundu et al (1994), Koopman and Fahnline (1997), Constans et al (1998), Milsted et al (1993) and Du and Olhoff (2007). In the works of Koopman and Fahnline (1997) and Du and Olhoff (2007), general (i.e., valid for arbitrary structures) expressions for the sensitivities of the sound power with respect to design variables are derived, and subsequently used in the optimization strategy.…”

Section: Introductionmentioning

confidence: 99%

“…In the works of Koopman and Fahnline (1997) and Du and Olhoff (2007), general (i.e., valid for arbitrary structures) expressions for the sensitivities of the sound power with respect to design variables are derived, and subsequently used in the optimization strategy. However, such a sensitivity analysis and the associated optimization procedure is not only extremely cumbersome, but, is computationally intensive as well since both a structural and acoustic analysis has to be conducted at each iteration step (Milsted et al 1993;Du and Olhoff 2007). Hence, Constans et al (1998) and Milsted et al (1993) use non-gradient based approaches.…”

Section: Introductionmentioning

confidence: 99%

“…However, such a sensitivity analysis and the associated optimization procedure is not only extremely cumbersome, but, is computationally intensive as well since both a structural and acoustic analysis has to be conducted at each iteration step (Milsted et al 1993;Du and Olhoff 2007). Hence, Constans et al (1998) and Milsted et al (1993) use non-gradient based approaches. However, such nongradient approaches are also computationally intensive due to the large number of function evaluations that are required in such strategies.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of vibrating structures to reduce radiated noise

Nandy

Jog

2011

Struct Multidisc Optim

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In this work, we propose an approach for reducing radiated noise from 'light' fluid-loaded structures, such as, for example, vibrating structures in air. In this approach, we optimize the structure so as to minimize the dynamic compliance (defined as the input power) of the structure. We show that minimizing the dynamic compliance results in substantial reductions in the radiated sound power from the structure. The main advantage of this approach is that the redesign to minimize the dynamic compliance moves the natural frequencies of the structure away from the driving frequency thereby reducing the vibration levels of the structure, which in turn results in a reduction in the radiated sound power as an indirect benefit. Thus, the need for an acoustic and the associated sensitivity analysis is completely bypassed (although, in this work, we do carry out an acoustic analysis to demonstrate the reduction in sound power levels), making the strategy efficient compared to existing strategies in the literature which try to minimize some measure of noise directly. We show the effectiveness of the proposed approach by means of several examples involving both topology and stiffener optimization, for vibrating beam, plate and shell-type structures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optimization of vibrating structures to reduce radiated noise

Nandy

Jog

2011

Struct Multidisc Optim

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“…Applications of structural acoustic optimization to noise in cars that do not focus on the body are known by Milsted et al 39 who addressed noise radiation from engine structures, by Belegundu et al 2 in an example about an engine cover plate and by la Civita and Sestieri 22 who optimized the engine mounting system.…”

Section: Introductionmentioning

confidence: 99%

Investigation and Optimization of a Spare Wheel Well to Reduce Vehicle Interior Noise

Marburg

Hardtke

2003

J. Comp. Acous.

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Optimization of structures with the intention to reduce noise emission has become an efficient tool during the past decade. Various approaches and applications have been published and will be briefly reviewed in this paper. Then, the structural component model of a spare wheel well and the fluid model of a sedan cabin are described. The noise transfer function is defined as the sound pressure level in vicinity of the driver's ear due to a harmonic force excitation at engine supports. The frequency range of 0-100 Hz is considered. In a first investigation, it is tested whether stiffening of the entire structural component really decreases the noise transfer function. It can be seen that this stiffening mainly affects noise emission in the upper frequency range. In a contribution analysis, i.e. analysis of the surface contribution to the noise at the driver's ear, the original model and the stiffened model are compared. This contribution analysis includes frequency ranges by summation of contribution and/or contribution levels. Modification of the structure by design variables consists of modification of the shell geometry, i.e. curvature. Two regions are selected at the bottom of the wheel well. Optimization of 30 design variables leads to a gain of 1.15 dB in the objective function being the root mean square value of the sound pressure level at the driver's ear. Finally, we discuss the results. In most papers on structural acoustic optimization, higher decreases have been reported. An explanation is provided, why this was not possible for the structure that has been investigated here. The new shape, however, seems to be a reasonable choice.

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“…15 Some approaches address the acoustic problem by reducing the volume velocity on the surface of the vibrating body. 16 The contribution in this paper is to present a design approach for reducing sound power radiated from general shell structures. This work has been possible largely due to the development of the POWER code, which can compute radiated sound power from general threedimensional shell structures.…”

Section: Introductionmentioning

confidence: 99%

Design Approach for Minimizing Sound Power from Vibrating Shell Structures

1998

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A design approach for minimizing sound power radiation from vibrating thin shell structures is presented. The method couples finite element analysis for determining structural modes and vibrations with a boundary element/wave superposition code for determining sound power radiation. Noise reduction is accomplished herein by optimal placement and sizing of small point masses on the structure. These masses alter the critical mode shapes so as to reduce sound power. The simulated annealing technique is used to determine the location and/or magnitude of the point masses. A computer program has been developed for design. Design examples are presented with the use of the computer program.

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A Numerical Method for Noise Optimization of Engine Structures

Cited by 13 publications

References 3 publications

Optimization of vibrating structures to reduce radiated noise

Optimization of vibrating structures to reduce radiated noise

Investigation and Optimization of a Spare Wheel Well to Reduce Vehicle Interior Noise

Design Approach for Minimizing Sound Power from Vibrating Shell Structures

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