Propagation characteristics of lamb waves in stringer-stiffened panels

Stringer-stiffened plate-like structure is a typical engineering structure and its structural integrity is critical. A guided Lamb wave-based damage identification scheme and an online structural health monitoring (SHM) system with an integrated PZT-sensor network were developed. In the previous studies, the specimens were relatively simple. In this paper, the above mentioned method was extended to the stiffened plate-like structure—a flat plate reinforced by stringer. FE dynamic simulation was applied to investigate the Lamb wave propagation characteristics due to the existence of stringer with the consideration of its material and geometric configurations.

Development of a building integrated photovoltaic/thermal solar energy cogeneration system

Using renewable energy sources for onsite cogeneration from structural building elements is a relatively new concept and is gaining considerable interest. In this study the design, development, manufacturing and testing of a novel building integrated photovoltaic/thermal (BIPVT) solar energy cogeneration system is discussed.

Adhesives (ADH), resistance seam welding (RSW) and autoclaving (ATC) were identified as the most appropriate for fabricating BIPVT roofing panels. Of these manufacturing methods ADH was found to be most suitable for low volume production systems due to its low capital cost.

A prototype panel, fabricated using ADH methods, exhibited good thermal performance. It was also shown that BIPVT performance could be theoretically predicted using a one dimensional heat transfer model and showed excellent agreement with experimental data. The model was used to suggest further design improvements. Finally, a transient simulation of the BIPVT was performed in TRNSYS and is used to illustrate the benefits of the system.

Sound absorption characteristics of a precast panel system made from environmentally sustainable concrete

This paper investigates the sound absorption characteristics of a precast panel system made from an environmentally sustainable concrete which can be used as an acoustical material. A current research project undertaken at the School of Architecture and Building, Deakin University, aims at utilising alternative materials and innovative approach to concrete precasting in the production of architecturally pleasing concrete panels. The normal incidence sound absorption coefficients of the assemblies were measured using an impedance tube. In general, the peak frequencies reduced with increasing thickness of concrete. The preliminary results indicate that the sound absorption of a three-layer variation of the panel meet design specifications related to acoustic performance. The major benefits of this investigated approach to concrete and concrete precasting are the ease of tunability to specific peak frequency, improved aesthetics and utilisation of industrial waste.

On the acoustic performance of a precast panel system made from environmentally sustainable concrete : application in sports hall buildings

The use of green building materials and products promotes conservation of non-renewable resources and help reduce associated environmental impacts. This article reports the acoustical performance of a precast panel system made largely from concrete waste material. Two major applications for such panels that are being investigated currently include walls and claddings to industrial and commercial buildings and sound barriers for urban freeways. In this study, the application of the concrete panels for optimizing reverberation time (RT) in sports halls is tested using numerical simulations. As an innovative approach, additional layers are added to the precast panels to improve their appearance. The absorption coefficients of the concrete panel improved significantly with the architectural finish. The material can be tuned according to the required peak frequency. The architectural finish helped reduce the RT for frequencies above 500 Hz. Its application to different types of ceilings revealed that the RT of curved ceiling reduced up to 40% compared to flat and hybrid ceiling. A comparison of wall and ceiling modifications in small, medium and large sports halls showed that medium-sized halls have better acoustical performance compared with small and large halls with ceiling as well as wall treatment.