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Material Research Related to structural Pavement failure on Motorway A32 in the Netherlands

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武汉理工大学学报 2010年第17期32卷 8-17页

作者： HOUBEN L J M MOLENAAR A A A ERKENS S M J G Faculty Civil Engineering and Geosciences Delft University of Technology Ministry of Traffic Public Works and Water ManagementCentre for Transport and Navigation

In 2008 structural failures occurred on the asphalt pavement,with a hydraulic blast furnace slag base,of the motorway A32 (constructed in 1986～1988) in the Netherlands. Within a few weeks serious depressions occurred,in which the asphalt pavement was full of cracks and the base had a very low stiffness. In 2008 and 2009 the pavement including the base was rehabilitated over a length of 10 *** Dutch Ministry of Public Works has initiated an extensive research into the risks of occurrence of this type of unexpected structural damages on the main road network in the Netherlands. Among many other things this research includes material research into the base material of the A32 to find the cause of the structural *** total 130 cores,divided over 26 cross-sections,were drilled from the A32. The cross-sections were divided over 3 areas,with a high and low base stiffness respectively and also at heaves that had grown into the pavement since 1998. In areas with high base stiffness the cores mainly contained bound base material,in areas with low base stiffness mainly granular material and at the heaves it was a mix thereof. Standard (static) and dynamic crushing tests were done on the granular material. Dynamic and monotonic indirect tensile tests and compression tests were performed on the bound material. In all cases no systematic difference was found between the mechanical properties of the blast furnace slag base material from the heavily loaded right traffic lane and the material from the other *** is concluded that the pavement failure on the A32 is introduced by the occurrence of full depth asphalt fatigue cracks in the pavement that was originally designed for 12 years (but was never strengthened) in areas where the base stiffness always has been low or became low through crushing (that also has resulted in the heaves). Penetrated rainwater then has weakened the base and pumping has occurred,resulting into loss of bearing capacity and decrease of vo

关键词： structural failure blast furnace slags base laboratory testing

Effects of intermediate stress on deep rock strainbursts under true triaxial stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第3期15卷 659-682页

作者： Lihua Hu Liyuan Yu Minghe Ju Xiaozhao Li Chun’an Tang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China Sate Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian116024China Key Laboratory of Disaster Prevention and structural Safety of Ministry of Education School of Civil and Architecture EngineeringGuangxi UniversityNanning530004China

The effect of intermediate stress(in situ tunnel axial)on a strainburst is studied with a threedimensional(3D)bonded block distinct element method(DEM).A series of simulations of strainbursts under true triaxial in situ stress conditions(*** tangential stress,moderate intermediate stress and low radial stress)of near-boundary rock masses are *** with the experimental results,the DEM model is able to capture the stress-strain response,failure pattern and energy balance of *** fracturing processes of strainbursts are also numerically *** results show that,as the intermediate stress increases:(1)The peak strain of strainbursts increases,the yield stress increases,the rock strength increases linearly,and the ratio of yield stress to rock strength decreases,indicating that the precursory information on strainbursts is enhanced;(2)Tensile and shear cracks increase significantly,and slabbing and bending of rock plates are more pronounced;and(3)The stored elastic strain energy and dissipated energy increase linearly,whereas the kinetic energy of the ejected rock fragments increases approximately exponentially,implying an increase in strainburst *** comparing the experimental and numerical results,the effect of intermediate stress on the rock strength of strainbursts is discussed in order to address three key ***,the Mogi criterion is applied to construct new strength criteria for strainbursts by converting the one-face free true triaxial stress state of a strainburst to its equivalent true triaxial stress *** summary,the effect of intermediate stress on strainbursts is a double-edged sword that can enhance the rock strength and the precursory information of a strainburst,but also increase its intensity.

关键词： Strainbursts Intermediate stress Distinct element method(DEM) structural failure True triaxial Strength criterion

Loss Factors and their Effect on Resonance Peaks in Mechanical Systems

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Sound & Vibration 2023年第1期57卷 1-13页

作者： Roman Vinokur Independent Consultant Woodland HillsSan Diego91367USA

The loss factors and their effects on the magnitude and frequency of resonance peaks in various mechanical sys-tems are reviewed for acoustic,vibration,and vibration fatigue *** main trends and relationships were obtained for linear mechanical models with hysteresis *** well-known features(complex module of elasticity,total loss factor,etc.)are clarified for practical engineers and students,and new results are presented(in particular,for 2-DOF in-series models with hysteresis friction).The results are of both educational and prac-tical interest and may be applied for NVH analysis and testing,mechanical and aeromechanical design,and noise and vibration control in buildings.

关键词： Mechanical loss factor resonance peak acoustics vibration structural failure noise NVH engineering systems

Reasons for Charles de Gaulle Airport Collapse

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Journal of Civil Engineering and Architecture 2017年第5期11卷 411-419页

作者： Toomas Kaljas Rak Tek Solutions Oy Helsinki Ylaituvantie 8 L/21 Finland

In the early morning hours of May 23, 2004, passengers in Terminal 2E at the Charles de Gaulle Airport in Paris partially collapsed resulting in several fatalities. structural failure was caused by multiple reasons, all contributing to failure. Similar structures have been successfully erected and built around the world. One famous and comparable structure is the Berlin Main Railway Station. After investigations, it becomes clear that Charles de Gaulle Airport lacks suitable and effective geometry, which is present in Berlin Railway Station.

关键词： Charles de Gaulle airport collapse structural failure inadequate external reinforcement geometry.

Investigating the failure mechanism of solid electrolyte interphase in silicon particles from an electrochemical-mechanical coupling perspective

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Advanced Powder Materials

Advanced Powder Materials 2024年第4期3卷 27-35页

作者： Junjie Ding Xueyan Li Lili Gong Peng Tan Department of Thermal Science and Energy Engineering University of Science and Technology of China(USTC)Hefei230026China State Key Laboratory of Fire Science University of Science and Technology of China(USTC)Hefei230026China

Silicon is considered one of the most promising anode materials owing to its high theoretical energy density,however,the volume expansion/contraction during electrochemical lithiation/delithiation cycles leads to instability of the solid electrolyte interphase(SEI),which ultimately results in capacity ***,the local stress and deformation evolution status of an SEI layer on an anode particle are investigated through a quantitative electrochemical-mechanical *** impacts of structural uniformity,mechanical strength,and operating conditions on the stability of the SEI layer are investigated in *** simulation results demonstrate that when the silicon particle radius decreases from 800 nm to 600 and 400 nm,the failure time increases by 29%and 65%,respectively,of the original failure time;When the structural defect depth ratio is reduced from 0.6 to 0.4 and 0.2,the failure time increases by 72%and 132%,respectively;For the discharge rate,the condition at 0.1 C has 34%and 139%longer time to failure than that at 0.2 C and 0.3 C,*** work provides insight into the rational design of stable SEI layers and sheds light on possible methods for constructing silicon-based lithium-ion batteries with longer cycling lives.

关键词： Solid electrolyte interface Silicon electrode structural failure Lithium-ion battery Modeling and simulation