Rectangular steel box girders offer advantages such as a simple frame, high stability, and strong bearing capacity. Despite their widespread use, these are susceptible to vortex-induced vibration (VIV), posing challenges the wind-resistant design. This study aims comprehensively understand VIV characteristics of different rectangular girders, based on which effective suppression measures proposed. First, with aspect ratios 4:1, 6.7:1, 9:1 selected investigate performance through sectional...

Long-span bridges with the Π-shaped composite girder are prone to significant vortex-induced vibrations (VIVs) because of odious flow around blunt deck. In this paper, VIV performance a and suppression efficiency different shaped fairings were systematically studied through experimental numerical approaches. Severe VIVs original observed in wind tunnel tests, installation lower central vertical stabilizer (LCVS) can reduce but cannot eliminate it thoroughly. Then, mechanism triggering LCVS...

The vortex-induced vibration (VIV) of the streamlined closed-box girder is greatly affected by attachments. Herein, VIV performance and suppression measures a with an aspect ratio 12.425 are investigated through 1:25 scale section model wind tunnel tests numerical simulations. Severe torsional VIVs at 0° +5° attack angles observed in tests. Subsequently, triggering mechanism explored computational fluid dynamics (CFD) method dynamic mesh technology. Furthermore, it pointed out that measure...

The Π-type steel-concrete composite girder, a commonly used bridge deck composed of an upper concrete slab and two lower lateral I-side steel girders, often suffers from severe vortex-induced vibrations (VIVs). Herein, the VIV response triggering mechanism girder are systematically investigated, by adopting 1:50 scale section model wind tunnel tests flow-field numerical simulations. Afterward, several aerodynamic measures were designed to mitigate significant VIVs present in original...

NiCu is one of the widely used thin-film materials, which now commonly as sensor and resistor in very-large-scale-integration (VLSI) because its high resistivity stability. However, with scale decreasing temperature increasing service condition, limited reliability material has been a key issue microelectronics packaging industry mainly due to current induced electromigration (EM). In this paper, sandwich-like (Ta/NiCu/Ta) thickness 120 nm was fabricated on glass substrate by sputtering...

Thermal design and thermal management are the key issues for electronic products during trend of miniaturization. Heat sink is one promising popular choices to relieve problem. In this paper, effect heat on electromigration (EM) lifetime Ni thin films investigated. It proved that had no influence temperature coefficient resistance (TCR), but could reduce rise (TR) raise breakdown voltage efficiently. The failure data with time obtained by accelerated test were analyzed ALTA software based...

It is well known that the flutter performance of a section sensitive to changing wind angles attack. Exploring thin plate’s mechanism under different attack excellent, which helps understand inner characteristics and ensures structural safety. This study investigated derivatives plate with an aspect ratio 40 via forced vibration technique. The otherness aerodynamic damping phase lag angles, in understanding mechanism, are analyzed using bimodal-coupled method. shown coupled...

The lower semi‐open box (LSOB) girder is widely used in large‐span bridges due to its favorable stress performance and cost‐effectiveness. vortex‐induced vibration (VIV) of the LSOB was studied by using a 1:55 section model wind tunnel test. test results show that there are obvious vertical torsional VIV intervals with significant amplitudes at each angle attack damping ratios about 0.35%. CFD numerical simulations indicate VIVs girders mainly induced two types vortices: one inclined webs...

Since 3D-TSV technology has been more and popular aiming at the demand of lightweight multi-functions electronic devices in recent years, μ-C4 bumps with smaller size which interconnect stacked die will suffer serious operating stress, even one thousands fails, device fail. Hence, it is meaningful to study reliability higher density bumps. In this paper, influence Cu/Al substrate thickness on strain fatigue life during thermal cycle studied by finite element analysis (FEA), since have large...

Anisotropic conductive adhesive (ACA) offers a promising solution for fine-pitch interconnections, which is low cost, temperature and environmentally clean. Good mechanical property high reliability are both required ACAs to be an alternative of solders. In this study, three types one lead-free solder were selected investigate their properties reliabilities. Shear strength test was conducted study the samples. Reflow performed examine if ACA could compatible with SMT process, shock...

Moving from single service systems to multiple services raises new challenges in multi-media LEO communication networks. Particularly, bandwidth allocation becomes more crucial for efficient use of wireless resources. In this paper, an adaptive method is presented. The approach based on the fact that a multimedia call alterable and problem formulated as constrained nonlinear optimization which aims at maximizing satisfaction degree system. A genetic algorithm developed solve problem....

Solder bump joint has been accepted as a main FCOB interconnection method so far. To optimize the process conditions for achieving SAC305 solder bumped assembly with maximum die shear strength and allowable void rate, an orthogonal experimental design of four factors three levels was carried out. The optimal are: 100 seconds preheating time, 245 °C peak temperature, 60 time above liquidus, flux paste auxiliary material. Three fracture modes were observed categorized samples after test based...

In low earth orbit (LEO) satellite communication systems, frequent intra- and inter-satellite handoffs are caused by the high-speed relative motion between Earth satellite. Then lead to a great call dropping probability which is main parameter for system's QoS. this paper, Genetic Algorithm (GA) based adaptive bandwidth allocation scheme presented. Aiming at multi-services focus on QoS expressed customers' satisfaction degree handoff probability. The effectiveness of proved simulation results.