Estimation of Fatigue Life of Long-Span Bridge by Considering Vehicle-Bridge Coupled Vibration
To estimate the fatigue life of long-span steel bridge more accurately, this paper proposes a method for estimating the fatigue life of long-span bridges by considering vehicle-bridge coupled vibration. Firstly, the universal equation of vehicle-bridge vibration is derived based on triaxial standard multi-scale model of fatigue vehicle and bridge, and relevant program for vehicle-bridge coupled vibration is programmed. Secondly, a method for estimating the fatigue life of long-span steel bridge is proposed based on fracture mechanics theories, and the analysis process is expounded in details. Finally, the method for estimating fatigue life proposed in this paper is verified by taking a double pylon cable- stayed bridge with orthotropic steel bridge deck slab as an example.
Spectra of Road Surface Roughness on Bridges
The power spectral density (PSD) of road surface roughness on highway bridges is presented. Eighty-four lines of 56 bridges were measured and the road surface roughness was measured by surveyor's level. The PSD is assumed by a stationary normal probability process with a zero mean value, and is calculated by a maximum entropy method (MEM) to a measured value of road surface roughness. Numerical examples are presented to obtain the information of road surface roughness on bridges in spectral characteristics, and to give the appropriate PSD using the dynamic response analysis of bridges under moving vehicles.
Chip scale packaging using chip-on-flex technology
An increasing number of electronic designers, fabricators and users see Chip Scale Packaging (CSP) as a way to obtain the benefits foreseen in multichip packaging and Chip-on-Board (COB) without the problems and limitations currently associated with each. The Chip-on-Flex (COF) multichip packaging technology has been demonstrated to be applicable to single chip packages that meet chip scale packaging goals. This paper looks at the Chip-on-Flex Chip Scale technology and addresses issues including the process, structure, assembly, yields and reliability.