Mechanical Behavior of Single-Layer Two-Way Grid Cylindrical Latticed Shell with Out-of-Plane Tension Members
Single layer two-way grid shell with in-plane and out-of-plane tension members is a new type of single-layer latticed shell roof. This study treats the effects of tension member installation on the buckling load and strength of a single layer two-way grid cylindrical shell roof by the numerical method. The tension members are installed to stiffen the rigidity of a single layer two-way grid shell roof and improve its stability behavior. Tension member installation and placement pattern is focused as both diagonal members of two-way grids and out-of-plane stiffened members in a cylindrical surface. The diagonal member and the out-of-plane member are used to increase the in-plane and the out-of- plane rigidity of a single layer two-way grid shell, respectively. The tension member placement pattern, the load distribution patterns, the initial imperfections and the initial axial force are considered for the numerical calculation parameters. It is confirmed by the numerical analysis that the tension members in out-of-plane and diagonals caused the increase in the buckling and strength of two-way grid shell.
Design, tests and realization of suspen-dome system
A structural system that the authors named suspen-dome is a type of space structure consisting of a single-layer truss dome and a tensegric network which stiffens the former by inversely loading it. The paper is an overview of the general characteristics of this system, and the objectives, statical advantages, a series of experiments made to prove the increase in buckling capacity, construction of two buildings of this system and statical and dynamical test carried on those buildings are reported.
Simplified impedance design and control for low-cost high-speed channels
Impedance design is the fundamentals of signal integrity at the very beginning, but controlled impedance is always costly or time-consuming for the high-speed channels. In this paper, many simulations of channel parasitics were taken and calculated that met with the specified impedances and correlated to the measurements very well. Selection of the different substrate stack-up without any layout modification in the BGA package reversed from the failed verification to pass the differential return loss. Adjustment of lead widths and spaces in the limited room of leadframe package improved 6 Ω of differential-mode impedance compared to the conventional leadframe packages. The differential pairs with wider traces routed on the 2-layer PCB are more robust for over-etching effects whose impedance errors are less than 5% without special impedance control. Moreover, those pairs inserted with a thin ground trace achieved 90 Ω differential-mode impedance and 28.2 Ω common-mode impedance simultaneously with 35% less routing area for MHL application and reserved a 10 Ω series resistor for ESD protection. With those diligent designs, the leadframe package and the 2-layer PCB can be still adopting in the consumer electronics for high-speed applications.