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Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel consideringriveting residual stress

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0701-7

摘要: The multi-material assembled light alloy wheel presents an effective lightweight solution for new energy vehicles, but its riveting connection remains a problem. To address this problem, this paper proposed the explicit riveting-implicit springback-implicit fatigue/explicit impact sequence coupling simulation analysis method, analyzed the fatigue and impact performance of the punching riveting connected magnesium/aluminum alloy (Mg/Al) assembled wheel, and constructed some major evaluation indicators. The accuracy of the proposed simulation method was verified by conducting physical experiments of single and cross lap joints. The punching riveting process parameters of the assembled wheel joints were defined as design variables, and the fatigue and impact performance of the assembled wheel was defined as the optimization objective. The connection-performance integration multi-objective optimization design of the assembled wheel considering riveting residual stress was designed via Taguchi experiment, grey relational analysis, analytic hierarchy process, principal component analysis, and entropy weighting methods. The optimization results of the three weighting methods were compared, and the optimal combination of design variables was determined. The fatigue and impact performance of the Mg/Al assembled wheel were effectively improved after optimization.

关键词: magnesium/aluminum assembled wheel     riveting residual stress     fatigue analysis     impact analysis     multi-objective optimization    

Impact analysis of compressor rotor blades of an aircraft engine

Y B SUDHIR SASTRY, B G KIROS, F HAILU, P R BUDARAPU

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 505-514 doi: 10.1007/s11709-018-0493-3

摘要: Frequent failures due to foreign particle impacts are observed in compressor blades of the interceptor fighter MIG-23 aircraft engines in the Ethiopian air force, supplied by the Dejen Aviation Industry. In this paper, we made an attempt to identify the causes of failure and hence recommend the suitable materials to withstand the foreign particle impacts. Modal and stress analysis of one of the recently failed MIG-23 gas turbine compressor blades made up of the following Aluminum based alloys: 6061-T6, 7075-T6, and 2024-T4, has been performed, apart from the impact analysis of the rotor blades hit by a granite stone. The numerical results are correlated to the practical observations. Based on the modal, stress and impact analysis and the material properties of the three considered alloys, alloy 7075-T6 has been recommended as the blade material.

关键词: axial flow compressor     rotor and stator blades     aircraft engine     stress and impact analysis     aluminum alloys    

Game theoretic analysis of environmental impact assessment system in China

CHENG Hongguang, PU Xiao, GONG Li, QI Ye

《环境科学与工程前沿(英文)》 2007年 第1卷 第4期   页码 448-453 doi: 10.1007/s11783-007-0071-8

摘要: Environmental impact assessment (EIA) system has been established in China since 1973. In present EIA cases, there are four participants in general: governments, enterprises, EIA organizations and the public. The public has held re

关键词: public     impact assessment     Environmental impact     general    

Dynamical analysis of droplet impact spreading on solid substrate

Zhaomiao LIU, Huamin LIU, Xin LIU,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 308-315 doi: 10.1007/s11465-010-0020-2

摘要: This paper investigates the impact spreading of a droplet on a solid substrate using numerical simulation on the basis of a volume-of-fluid (VOF) model. The process of droplet spreading is described, the analysis of low speed and high speed droplet spreading, and more than one droplet spreading simultaneously is performed. The pressure, velocity, and spreading factor during the droplet spreading are reported. According to the spreading factor’s evolvement, the process of droplet spreading can be classified into spreading phase and recoiling phase. The spreading factors are almost the same at the low speed droplet spreading; however, the pressures on the substrate are quite different and air entrainment may be found as the impact speeds in a certain range. The impact speed impacts on the spreading factors in high speed droplet spreading. The spreading factor obviously increases with increasing impact speed; however, splashing will appear in the status when the speed is high enough in the high speed droplet spreading. The distance between the neighbor droplets affects the film’s quality, and only the distance between the static diameter and the maximum diameter can ensure the film’s quality. The results could help in understanding the process of droplet spreading and provide advice on the operation of a spray coating process.

关键词: droplet     impact spreading     numerical simulation    

Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

《结构与土木工程前沿(英文)》 2021年 第15卷 第3期   页码 595-608 doi: 10.1007/s11709-021-0720-1

摘要: The effective notch stress approach for evaluating the fatigue strength of rib–deck welds requires notch stress concentration factors obtained from complex finite element analysis. To improve the efficiency of the approach, the notch stress concentration factors for three typical fatigue-cracking modes (i.e., root–toe, root–deck, and toe–deck cracking modes) were thoroughly investigated in this study. First, we developed a model for investigating the effective notch stress in rib–deck welds. Then, we performed a parametric analysis to investigate the effects of multiple geometric parameters of a rib–deck weld on the notch stress concentration factors. On this basis, the multiple linear stepwise regression analysis was performed to obtain the optimal regression functions for predicting the notch stress concentration factors. Finally, we employed the proposed formulas in a case study. The notch stress concentration factors estimated from the developed formulas show agree well with the finite element analysis results. The results of the case study demonstrate the feasibility and reliability of the proposed formulas. It also shows that the fatigue design curve of FAT225 seems to be conservative for evaluating the fatigue strength of rib–deck welds.

关键词: notch stress concentration factor     rib–deck weld     parametric analysis     regression analysis     parametric equation    

Comparative analysis of impact of human occupancy on indoor microbiomes

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-020-1383-1

摘要:

• Exposure to indoor microbiomes is a public health concern in educational facilities.

关键词: Built environment     Indoor microbiome     Occupant     Building     Sequencing    

Total stress rapid drawdown analysis of the Pilarcitos Dam failure using the finite element method

Daniel R. VANDENBERGE

《结构与土木工程前沿(英文)》 2014年 第8卷 第2期   页码 115-123 doi: 10.1007/s11709-014-0249-7

摘要: Rapid drawdown is a critical design condition for the upstream or riverside slope of earth dams and levees. A new total stress rapid drawdown method based on finite element analysis is used to analyze the rapid drawdown failure that occurred at Pilarcitos Dam in 1969. Effective consolidation stresses in the slope prior to drawdown are determined using linear elastic finite element analysis. Undrained strengths from isotropically consolidated undrained (ICU) triaxial compression tests are related directly to the calculated consolidation stresses and assigned to the elements in the model by interpolation. Two different interpretations of the undrained strength envelope are examined. Strength reduction finite element analyses are used to evaluate stability of the dam. Back analysis suggests that undrained strengths from ICU tests must be reduced by 30% for use with this rapid drawdown method. The failure mechanism predicted for Pilarcitos Dam is sensitive to the relationship between undrained strength and consolidation stress.

关键词: rapid drawdown     finite element     total stress     slope stability    

Risk-based probabilistic thermal-stress analysis of concrete arch dams

Narjes SOLTANI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

《结构与土木工程前沿(英文)》 2019年 第13卷 第5期   页码 1007-1019 doi: 10.1007/s11709-019-0521-y

摘要: The probabilistic risk of arch dam failure under thermal loading is studied. The incorporated uncertainties, which are defined as random variables, are associated with the most affecting structural (material) properties of concrete and thermal loading conditions. Karaj arch dam is selected as case study. The dam is numerically modeled along with its foundation in three-dimensional space; the temperature and thermal stress distribution is investigated during the operating phase. The deterministic thermal finite element analysis of the dam is combined with the structural reliability methods in order to obtain thermal response predictions, and estimate the probability of failure in the risk analysis context. The tensile overstressing failure mode is considered for the reliability analysis. The thermal loading includes ambient air and reservoir temperature variations. The effect of solar radiation is considered by an increase in the ambient temperatures. Three reliability methods are employed: the first-order second-moment method, the first-order reliability method, and the Monte-Carlo simulation with Latin Hypercube sampling. The estimated failure probabilities are discussed and the sensitivity of random variables is investigated. Although most of the studies in this line of research are used only for academic purposes, the results of this investigation can be used for both academic and engineering purposes.

关键词: arch dams     probabilistic analysis     thermal stress     sensitivity     reliability    

Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

Pengfei LI; Jinquan ZHANG; Shengqi MEI; Zhenhua DONG; Yan MAO

《结构与土木工程前沿(英文)》 2022年 第16卷 第2期   页码 239-249 doi: 10.1007/s11709-021-0804-y

摘要: Damping is known to have a considerable influence on the dynamic behavior of bridges. The fixed damping ratios recommended in design codes do not necessarily represent the complicated damping characteristics of bridge structures. This study investigated the application of stress-dependent damping associated with vehicle-bridge coupling vibration and based on that investigation proposed the stress-dependent damping ratio. The results of the investigation show that the stress-dependent damping ratio is significantly different from the constant damping ratio (5%) defined in the standard specification. When vehicles travel at speeds of 30, 60, and 90, the damping ratios of the bridge model are 3.656%, 3.658%, and 3.671%, respectively. The peak accelerations using the regular damping ratio are 18.9%, 21.3%, and 14.5% of the stress-dependent damping ratio, respectively. When the vehicle load on the bridge is doubled, the peak acceleration of the mid-span node increases by 5.4 times, and the stress-related damping ratio increases by 2.1%. A corrugated steel-web bridge is being used as a case study, and the vibration response of the bridge is compared with the measured results. The acceleration response of the bridge which was calculated using the stress-dependent damping ratio is significantly closer to the measured acceleration response than that using the regular damping ratio.

关键词: vehicle-bridge vibration system     dynamic analysis     stress-dependent damping     energy dissipation    

Thermal fluid-structure interaction and coupled thermal-stress analysis in a cable stayed bridge exposed

Nazim Abdul NARIMAN

《结构与土木工程前沿(英文)》 2018年 第12卷 第4期   页码 609-628 doi: 10.1007/s11709-018-0452-z

摘要: In this paper, thermal fluid structure-interaction (TFSI) and coupled thermal-stress analysis are utilized to identify the effects of transient and steady-state heat-transfer on the vortex induced vibration and fatigue of a segmental bridge deck due to fire incidents. Numerical simulations of TFSI models of the deck are dedicated to calculate the lift and drag forces in addition to determining the lock-in regions once using fluid-structure interaction (FSI) models and another using TFSI models. Vorticity and thermal convection fields of three fire scenarios are simulated and analyzed. Simiu and Scanlan benchmark is used to validate the TFSI models, where a good agreement was manifested between the two results. Extended finite element method (XFEM) is adopted to create 3D models of the cable stayed bridge to simulate the fatigue of the deck considering three fire scenarios. Choi and Shin benchmark is used to validate the damaged models of the deck in which a good coincide was seen between them. The results revealed that TFSI models and coupled thermal-stress models are significant in detecting earlier vortex induced vibration and lock-in regions in addition to predicting damages and fatigue of the deck due to fire incidents.

关键词: fire scenario     transient heat transfer     TFSI model     coupled thermal-stress     XFEM    

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

《机械工程前沿(英文)》 2014年 第9卷 第3期   页码 281-294 doi: 10.1007/s11465-014-0307-9

摘要:

In this study, the stress concentration factors (SCF) in cross-and-angle-ply laminated composite plates as well as in isotropic plates with single circular holes subjected to uniaxial loading is studied. A quadrilateral finite element of four-node with 32 degrees of freedom at each node, previously developed for the bending and mechanical buckling of laminated composite plates, is used to evaluate the stress distribution in laminated composite plates with central circular holes. Based up on the classical plate theory, the present finite element is a combination of a linear isoparametric membrane element and a high precision rectangular Hermitian element. The numerical results obtained by the present element compare favorably with those obtained by the analytic approaches published in literature. It is observed that the obtained results are very close to the reference results, which demonstrates the accuracy of the present element. Additionally, to determine the first ply failure (FPF) of laminated plate, several failure criterions are employed. Finally, to show the effect of ratio on the failure of plates, a number of figures are given for different fiber orientation angles.

关键词: laminated composite plates     stress concentration     geometric singularity     anisotropic effect    

Quantitative analysis of impact of green stormwater infrastructures on combined sewer overflow control

Jinsong Tao, Zijian Li, Xinlai Peng, Gaoxiang Ying

《环境科学与工程前沿(英文)》 2017年 第11卷 第4期 doi: 10.1007/s11783-017-0952-4

摘要: Stimulated by the recent USEPA’s green stormwater infrastructure (GSI) guidance and policies, GSI systems have been widely implemented in the municipal area to control the combined sewer overflows (CSOs), also known as low impact development (LID) approaches. To quantitatively evaluate the performance of GSI systems on CSO and urban flooding control, USEPA-Stormwater Management Model (SWMM) model was adopted in this study to simulate the behaviors of GSI systems in a well-developed urban drainage area, PSW45, under different circumstances. The impact of different percentages of stormwater runoff transported from impervious surfaces to the GSI systems on CSO and urban flooding control has also been investigated. Results show that with current buildup, GSI systems in PSW45 have the best performance for low intensity and short duration events on both volume and peak flow reductions, and have the worst performance for high intensity and long duration events. Since the low intensity and short duration events are dominant from a long-term perspective, utilizing GSI systems is considered as an effective measure of CSO control to meet the long-term control strategy for PSW45 watershed. However, GSI systems are not suitable for the flooding control purpose in PSW45 due to the high occurrence possibility of urban flooding during or after high intensity events where GSI systems have relatively poor performance no matter for a short or long duration event.

关键词: Green stormwater infrastructure (GSI)     Combined sewer overflows (CSOs)     Urban flooding     Low impact development (LID)     Stormwater Management Model (SWMM)    

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

《工程管理前沿(英文)》 2021年 第8卷 第1期   页码 88-97 doi: 10.1007/s42524-020-0063-y

摘要: Areas that are covered with natural vegetation have been converted into asphalt, concrete, or roofed structures and have increased surface impermeability and decreased natural drainage capability. Conventional drainage systems were built to mimic natural drainage patterns to prevent the occurrence of waterlogging in developed sites. These drainage systems consist of two major components: 1) a stormwater conduit system, and 2) a runoff storage system. Runoff storage systems contain retention basins and drywells that are used to store and percolate runoff, whereas conduit systems are combination of catch basins and conduit pipes used to collect and transport runoff. The construction of these drainage systems is costly and may cause significant environmental disturbance. In this study, low impact development (LID) methods that consist of extensive green roofs (GRs) and permeable interlocking concrete pavements (PICPs) are applied in real-world construction projects. Construction project documents were reviewed, and related cost information was gathered through the accepted bidding proposals and interviews of specialty contractors in the metropolitan area of Phoenix, Arizona. Results indicate that the application of both LID methods to existing projects can save an average of 27.2% in life cycle costs (LCC) for a 50-year service life and 18.7% in LCC for a 25-year service life on the proposed drainage system, respectively.

关键词: low impact development     traditional drainage system     hydraulic benefits     life-cycle cost    

Dynamic failure analysis on granite under uniaxial impact compressive load

ZHAI Yue, MA Guowei, HU Changming, ZHAO Junhai

《结构与土木工程前沿(英文)》 2008年 第2卷 第3期   页码 253-260 doi: 10.1007/s11709-008-0042-6

摘要: High strain-rate uniaxial compressive loading tests were produced in the modified split Hopkinson pressure bar (SHPB) with pulse shaper on granite samples. It was shown that the failure of the granite cylinder was typical tensile splitting failure mode by sudden splitting parallel to the direction of uniaxial compressive loading at different strain rates. Besides, it was concluded that not only the strength of granite increased, but also the fragment size decreased and the fragment numbers increased with the increasing strain rate. To quantitatively analyze the failure phenomena, the numerical calculation based on a dynamic interacting sliding microcrack model was adopted to investigate the influence of microcrack with the different initial crack length, crack angle, crack space and friction coefficient on the macro-mechanical properties of granite under different strain rates. Accordingly, the strain-dependency of the compression strength and the fragmentation degree of granite was explained reasonably.

关键词: numerical calculation     coefficient     cylinder     splitting parallel     strain-dependency    

Parameter studies on impact in a lap joint

Amir M. RAHMANI,Elizabeth K. ERVIN

《机械工程前沿(英文)》 2015年 第10卷 第1期   页码 64-77 doi: 10.1007/s11465-014-0322-x

摘要:

To represent a loose lap joint, a beam impacting four springs with gaps is modeled. Modal analysis with base excitation is solved, and time histories of contact points are closely monitored. Using the impulse during steady state response, six influential parameters are studied: damping ratio, contact stiffness, intermediate contact position, gap, excitation amplitude and beam height. For all parameters, the system response is highly controlled by modes with two contacting springs. Each parameter’s effect on system response is presented including unstable regions, unique trend behaviours result. Recommendations for structural designers are also noted.

关键词: impact mechanics     contact     joint behaviour     modal analysis     parameter study    

标题 作者 时间 类型 操作

Fatigue and impact analysis and multi-objective optimization design of Mg/Al assembled wheel consideringriveting residual stress

期刊论文

Impact analysis of compressor rotor blades of an aircraft engine

Y B SUDHIR SASTRY, B G KIROS, F HAILU, P R BUDARAPU

期刊论文

Game theoretic analysis of environmental impact assessment system in China

CHENG Hongguang, PU Xiao, GONG Li, QI Ye

期刊论文

Dynamical analysis of droplet impact spreading on solid substrate

Zhaomiao LIU, Huamin LIU, Xin LIU,

期刊论文

Parametric equations for notch stress concentration factors of rib–deck welds under bending loading

期刊论文

Comparative analysis of impact of human occupancy on indoor microbiomes

期刊论文

Total stress rapid drawdown analysis of the Pilarcitos Dam failure using the finite element method

Daniel R. VANDENBERGE

期刊论文

Risk-based probabilistic thermal-stress analysis of concrete arch dams

Narjes SOLTANI, Mohammad ALEMBAGHERI, Mohammad Houshmand KHANEGHAHI

期刊论文

Numerical analysis of vehicle-bridge coupling vibration concerning nonlinear stress-dependent damping

Pengfei LI; Jinquan ZHANG; Shengqi MEI; Zhenhua DONG; Yan MAO

期刊论文

Thermal fluid-structure interaction and coupled thermal-stress analysis in a cable stayed bridge exposed

Nazim Abdul NARIMAN

期刊论文

Finite element analysis of stress concentrations and failure criteria in composite plates with circular

null

期刊论文

Quantitative analysis of impact of green stormwater infrastructures on combined sewer overflow control

Jinsong Tao, Zijian Li, Xinlai Peng, Gaoxiang Ying

期刊论文

Life cycle cost savings analysis on traditional drainage systems from low impact development strategies

Pengfei ZHANG, Samuel T. ARIARATNAM

期刊论文

Dynamic failure analysis on granite under uniaxial impact compressive load

ZHAI Yue, MA Guowei, HU Changming, ZHAO Junhai

期刊论文

Parameter studies on impact in a lap joint

Amir M. RAHMANI,Elizabeth K. ERVIN

期刊论文