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The severe freezing and thawing in seasonally frozen soils is one of the main reasons for frost heave and thaw settlement of subgrade, which leads to cracks and other serious diseases of asphalt pavement. To study the impact of freezing and thawing of subgrades on the pavement structure, an on-site investigation of the asphalt pavement diseases in Tibet, China was conducted, and a 1:5 mock-up for laboratory tests and a finite element model were designed. The temperature and humidity of the subgrade and the stress and vertical deformation of the pavement were analyzed. It was found that the moisture content of the subgrade had a significant impact on the cracking of asphalt pavement, and the vertical displacement of pavement increased by about 0.6 mm when the moisture content increased by 5 %. If there were initial cracks in the semirigid base, the maximum principal stress of the asphalt surface layer was 2.1 times more than that without cracks, which could easily lead to serious diseases in asphalt pavement. The flexible base had a good deformation coordination, which reduced the damage of the frost heave to the asphalt pavement, thereby preventing cracks on the asphalt pavement. The research results provided a theoretical direction for the analysis of frost heave characteristics and a basis for the optimum design of pavement structures in cold regions. [ABSTRACT FROM AUTHOR]

Hot spots can lead to a failure of vehicular clutches. A theoretical model was constructed to investigate thermoelastic instability (TEI) and hot spots in automotive clutches. When the sliding speed exceeds the critical speed, a spatially temperature perturbation growing with time can lead to hot spots. Hot spots appear mainly on the mating disk because of its high Peclet number. Mating disk has an anti-symmetric deformation due to the critical speed. A material with low elastic modulus and high thermal conductivity can experience a high critical speed, while the thermal expansion coefficient has little effect on it. [ABSTRACT FROM AUTHOR]

The Lupu Bridge is a steel box tied arch bridge with a main span of 550 m, which held the world record of the longest arch span on its completion in 2003. This bridge has been the subject of controversy since its conceptual design; however, almost a decade has passed, and this bridge has become a landmark of Shanghai city while serving as the main traffic corridor connecting the two districts on the north and south river banks, especially during the 2010 world expo. This paper presents the background of the comparison and selection of the original bridge type, further structural optimization of the arch bridge conceptual design and the challenges that came up during the design and construction, along with their corresponding solutions. The successful design and construction of this bridge provides some valuable information, and moreover, a very useful engineering practice for long span arch bridges constructed on soft soil foundations. [ABSTRACT FROM AUTHOR]

This work is devoted to investigate the effects of thermal buckling on the tribological characteristics of a Cu-based wet clutch by artificially modifying friction pairs into different contact ratios. A thermal lubrication model is provided, and corresponding experiments are conducted on the wet clutch comprehensive test bench. The friction results from measurements and simulations for such modified friction pairs are analyzed. The results show that, as the contact ratio reduces, surface temperature rises obviously, and friction coefficient increases dramatically, so that local friction torque and total output torque grow significantly. In addition, the vibration of the output torque becomes more severe as the contact ratio reduces. Therefore, the nonuniform contact after thermal buckling exacerbates the friction characteristics of friction pairs severely and accelerates the failure of wet clutches. [ABSTRACT FROM AUTHOR]

An abstract of an article "Study on clutch engagement judder during launch process for dual clutch transmissions," by Jinle Zhang, Biao Ma, and Manfred Zehn is presented.