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Monolayer cable net system supporting glass facades is structurally sensitive to wind excitations. At present, there are limited researches on its wind-induced vibration performance, therefore it appears imperative to understand the wind-resistant behavior of this type of cable net. The wind-induced response of the monolayer cable net subjected to fluctuating wind loads is investigated with frequency-domain method in this paper, when the cable net deforms to the balance position under the mean wind loads. Some critical factors to wind-induced response are highlighted, including participation property of the modes in the dynamic vibration, and coupling effect among modes. The response spectrum of the cable net is also intensively investigated. It is shown that the first mode dominates wind-induced response significantly in all the modes, and the modes contributing to the wind-induced responses prominently are distributed in a narrow band of low order modes. When some lower modes and coupling effects among these modes are considered, the results in frequency domain agree well with the corresponding results obtained from time domain method, which are adequate for engineering practice. The characteristics of response spectrum of the nodal displacements are similar to those of the cable forces. When the wind loads and structural parameters vary in practical ranges in engineering, the resonant component in the total response sometimes occupies larger part in the total fluctuating wind response of the cable net, while the background component dominates in the wind response more commonly. Nevertheless, the first mode makes the largest contributions, no matter the background or the resonant component dominates. DOI: 10.1061/(ASCE)0733-9399(2010)136:3(311) CE Database subject headings: Wind loads; Excitation; Vibration; Cables. Author keywords: Monolayer cable net; Wind-induced response; Frequency domain; Mode; Coupling; Response spectrum.

Pore formation remains a concern in the area of rapid manufacturing by the laser engineered net shaping process. Results usually conflict on the origin of these pores; whether it should stem from an effect due to the physical/mechanical properties of the material or from an effect purely related to the processing parameters. We investigated this problem spanning a range of process parameters for deposition and using three different material powders, namely, an AISI 410 grade stainless steel, AISI 316L grade stainless steel, and AISI 4140 grade medium-carbon low alloy steel. The volume fraction, number density, and size distribution of pores were quantified using X-ray computed tomography and optical microscopy. Pores formed both at the interface between the adjacent layers and within the bulk of the laver. They were systematically sensitive to both the powder material composition and the process parameters. [DOI: 10.1115/1.3184087] Keywords: laser-assisted powder deposition, porosity, LENS, laser engineered net shaping