This thesis considers applications of gradient-based optimization algorithms to the design and control of some mechanics systems. The material distribution approach to topology optimization is applied to design two different acoustic devices, a reactive muffler and an acoustic horn, and optimization is used to control a ball pitching robot. Reactive mufflers are widely used to attenuate the exh...

The article considers the urgent issue of reducing toxicity harmful components car exhaust gases. In order to solve this problem, a direction was proposed improve system for cleaning gases internal combustion engines by introducing an ultrasonic emitter into muffler device. An experimental installation with made plan determining effectiveness based on method similarity theory and dimensional an...

The stealth capability of a submarine differentiates it from other maritime platforms. The power plant for many submarines exceeds 1 Mega-Watt and the technical challenge is to reduce its acoustic signature to unperceivable levels. Novel vibration reduction technologies have been developed and tested at the University of Adelaide as part of a DSTO Capability Technology Demonstrator program that...

Exhaust noise in engines has always been a major source of automotive noise. Challenges for muffler design have been constraints on size, back pressure, and, of course, the cost. Designing for sufficient insertion loss at the engine firing frequency and the first few harmonics has been the biggest challenge. Most advances in the design of efficient mufflers have resulted from linear plane wave ...

An alternative exhaust manifold system, the Perforated Manifold, Muffler, and Catalyst (PMMC), is proposed to improve sound suppression while reducing engine pumping losses and exhaust emissions. One-dimensional predictions from acoustic theory are used to configure the initial design. Preliminary evaluation of the concept is based on bench tests, including an extended impedance tube set-up for...

This paper considers the combined use of a hybrid numerical method for the modeling of acoustic mufflers and a genetic algorithm for multiobjective optimization. The hybrid numerical method provides accurate modeling of sound propagation in uniform waveguides with non-uniform obstructions. It is based on coupling a wave based modal solution in the uniform sections of the waveguide to a finite e...

This study was conducted to investigate the effects of engine operating conditions and exhaust aftertreatments on the mutagenicity of diesel particulate matter (DPM) collected directly in an underground mine environment. A number of after-treatment devices are currently used on diesel engines in mines, but it is critical to determine whether reductions in DPM concentrations result in a correspo...

Research on new techniques of single-chamber mufflers hybridized with an internal extended tube has been addressed; however, the research work on a space-constrained multi-chamber muffler hybridized with multiple internal extended tubes which may increase the acoustical performance within a specified back pressure has been ignored. Therefore, the analysis of a sound transmission loss (STL) for ...

This paper presents a CFD model of reverse-flow extended-tube muffler which is analyzed by a set of experimental tests, in order to acquire the relations between the structure and its corresponding pressure loss; a lot of research have been done through the numeric simulation. For the specific model, the distance from inlet pipe’s rear to the end cap has a large impact on the pressure loss, fur...