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This study is aimed at investigating the resilience degradation caused by traffic accidents and developing relevant resilience optimization strategies. A two-stage accident resilience triangle framework was proposed by comparing the differences between natural disasters and traffic accidents. To maximize system resilience, a network-wide traffic signal optimization model was presented. Spillback constraints and equilibrium constraints were established to enhance the capacity of urban-road networks to minimize congestion escalation, in addition to rapid recovery. A two-level algorithm based on greedy strategy and gradient descent was designed to solve the proposed non-linear programming model. In the experiment, a virtual road network was constructed based on the Simulation of Urban Mobility (SUMO) platform for validation and sensitivity analysis. The experimental results revealed that: (1) Compared to the traditional resilience framework, the proposed two-stage accident resilience framework can more reasonably describe the change mechanism of road network resilience under disturbance. (2) The proposed resilience-based traffic signal optimization model improved the system resilience under different conditions of traffic demand, accident severity, and rescue time in terms of the maximum performance degradation and recovery time. Precisely, the resilience loss is reduced by a maximum of 1.4%. Finally, the proposed model was further implemented with field data. The resilience improvement was significant during the evening rush hour. The results of this study contribute toward transportation resilience research and accident rescue strategies with respect to traffic management and control. [ABSTRACT FROM AUTHOR]

This paper presents a simple refined plate theory (S-RPT) which contains only three unknown variables in the displacement field for bending and buckling analysis and only one unknown variable in the displacement field for free vibration analysis. Unlike other simplified plate theories, S-RPT in its simplification (1) takes into account the Poisson's ratio variation along the thickness direction (2) takes into account the full coupling of in-plane and transverse displacements. These features make S-RPT applicable to the analysis of bending, buckling, and free vibration of functionally graded porous plates reinforced with graphene platelets (FGP–GPLs). Some simplified plate theories already available in the literature can be regarded as special cases of S-RPT. The S-RPT is first used in isotropic and metal–ceramic functionally graded plates to verify its accuracy. Then, the effect of pore distribution, GPLs distribution, porosity coefficient, aspect ratio, thickness ratio, and GPLs weight fraction on the bending, buckling, and free vibration behaviors are investigated based on S-RPT. [ABSTRACT FROM AUTHOR]

The cyclic loading experiments on HP‐172B sealant bonded tubular butt‐joints were carried out with the strain‐controlled mode, and the effects of strain amplitude and mean strain on the cyclic relaxation stress and cyclic softening variable of the bonded butt‐joint were investigated. The experimental results show that the stress–strain response curve of the butt‐joint presents a corrugated shape under cyclic loading. The cyclic stress relaxation and cyclic softening of the bonded butt‐joint occur. The increase of mean strain and strain amplitude intensifies the cyclic stress relaxation and cyclic softening behaviors. According to the experimental observation, a nonlinear viscoelastic model is proposed to predict the mechanical behavior of butt‐joints under cyclic loading, which considers the cyclic stress relaxation and cyclic softening of the bonded butt‐joint. The comparisons between the model calculation and the experimental data show that the calculated stress–strain curve is in good agreement with the experimental data. Highlights: The cyclic loading experiments on adhesively bonded joints were carried out.The stress–strain curve presents a corrugated shape under cyclic loading.A viscoelastic model was proposed according to the experimental observation.The model can describe the mechanical behaviors of adhesively bonded joints. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of TB991 weld sealant under cyclic loading conditions were experimentally investigated. The evolution of relaxation stress, cyclic softening, and dissipated energy was evaluated with the effect of strain amplitude and mean strain. The experimental results showed that the stress–strain response curves of the first loading‐unloading and cyclic loading‐unloading were significantly different. The phenomenon of stress relaxation and cyclic softening occurred under cyclic strain loading conditions. Furthermore, the relaxation stress and dissipated energy decreased rapidly during the initial cyclic loading and then steadily decreased with the increase of cycle number, while the cyclic softening increased rapidly at first and then steadily. Besides, a viscoelastic constitutive model was proposed which can describe the different shapes of stress–strain curve between the initial loading‐unloading and the cyclic loading‐unloading and also considers the cyclic stress relaxation and cyclic softening of the materials under cyclic loading condition. Comparisons between the numerical results and the experimental data demonstrated that the proposed model can better describe the mechanical behavior of TB991 weld sealant under cyclic loading conditions. TB991 weld sealant was experimentally investigated under cyclic loading conditions.The evolution of relaxation stress, cyclic softening, and dissipated energy was investigated.A constitutive model was proposed to describe the mechanical behavior of the material under cyclic loading conditions.The proposed model can consider the cyclic stress relaxation and cyclic softening of the materials. [ABSTRACT FROM AUTHOR]

With rapidly developing communication and autonomous-driving technology, traffic flow on road networks will change from homogeneous human-driven vehicle (HDV) traffic flow to heterogeneous mixed traffic flow (MTF) comprising HDVs, autonomous vehicles (AVs), and connective-and-autonomous vehicles (CAVs). To understand the changes in the MTF of transportation engineering, we investigated the reserved capacity (RC) and right-of-way (ROW) reallocation policy that should be utilized under MTF scenarios. We established an MTF-based theoretical model to calculate the expressway segment capacity, theoretically analyzed the influence of the market penetration rate (MPR) on capacity and validated the model through numerical analysis. The results showed that the MPR of AVs and CAVs can enhance the MTF RC that is within 0–200% and that the platooning rate of CAVs positively influences the MTF RC. CAV popularization does not necessarily lead to a rapid increase in the transportation system efficiency when the MPR is <40% but significantly improves the efficiency of existing urban transportation facilities. When the MPR is >40%, the greatest enhancement is 4800 pcu/h/lane in terms of RC. A ROW reallocation policy that equips CAV-dedicated lanes according to the MPR of AVs and CAVs can enhance the capacity of expressway systems by 500 pcu/h/lane in terms of RC. [ABSTRACT FROM AUTHOR]