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Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes
Daniel GAONA,Alfredo VALAREZO
《机械工程前沿(英文)》 2015年 第10卷 第3期 页码 294-300 doi: 10.1007/s11465-015-0351-0
The elastic modulus of a deposit (Ed) can be obtained by monitoring the temperature (?T) and curvature (?k) of a one-side coated long plate, namely, a one-dimensional (1D) deformation model. The aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory’s results. The ?k-?T slope error is less than 8%, and the Ed estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all ?k-?T curves (over 97%). The Ed values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of Ed. An example of a turbine-blade-shaped substrate is presented to validate the approach.
关键词: in-plane Young’s modulus curvature temperature thermal stress coating
《结构与土木工程前沿(英文)》 页码 812-826 doi: 10.1007/s11709-023-0940-7
关键词: falling weight deflectometer modulus of subgrade reaction elastic modulus metaheuristic algorithms
The stress relaxation of cement clinkers under high temperature
Xiufang WANG,Yiwang BAO,Xiaogen LIU,Yan QIU
《机械工程前沿(英文)》 2015年 第10卷 第4期 页码 413-417 doi: 10.1007/s11465-015-0357-7
The energy consumption of crushing is directly affected by the mechanical properties of cement materials. This research provides a theoretical proof for the mechanism of the stress relaxation of cement clinkers under high temperature. Compression stress relaxation under various high temperatures is discussed using a specially developed load cell, which can measure stress and displacement under high temperatures inside an autoclave. The cell shows that stress relaxation dramatically increases and that the remaining stress rapidly decreases with an increase in temperature. Mechanical experiments are conducted under various temperatures during the cooling process to study the changes in the grinding resistance of the cement clinker with temperature. The effects of high temperature on the load-displacement curve, compressive strength, and elastic modulus of cement clinkers are systematically studied. Results show that the hardening phenomenon of the clinker becomes apparent with a decrease in temperature and that post-peak behaviors manifest characteristics of the transformation from plasticity to brittleness. The elastic modulus and compressive strength of cement clinkers increase with a decrease in temperature. The elastic modulus increases greatly when the temperature is lower than 1000 °C. The compressive strength of clinkers increases by 73.4% when the temperature drops from 1100 to 800 °C.
关键词: stress relaxation high temperature cement clinker compression elastic modulus
Said CHOUCHA, Amar BENYAHIA, Mohamed GHRICI, Mohamed Said MANSOUR
《结构与土木工程前沿(英文)》 2018年 第12卷 第3期 页码 261-269 doi: 10.1007/s11709-017-0394-x
In order to determine the effect of Natural Pozzolan (NP) content on the mechanical properties and durability characteristics on Engineered Cementitious Composites (ECC) as repair material. This study focused on the evaluation of the most factors influencing compatibility between the repair material and the base concrete including mechanicals properties such as, compressive and flexural strengths, elastic modulus, capillary absorption and drying shrinkage. The experimental results showed that natural pozzolan reduces the compressive strength and the flexural strength of ECC at all ages. The elastic modulus of ECC was remarkably lower than that of normal-strength concrete. This lower Young’s modulus is desirable for repair concrete, because it prevents the stresses induced by restrained shrinkage. In addition, the incorporation of high-volume natural pozzolan decreases significantly the coefficient of capillary absorption at long term and increases the drying shrinkage. Generally, based on the results obtained in the present experimental investigation, ECC can be used effectively as an overlay material over existing parent concrete.
关键词: natural pozzolan engineered cementitious composites mechanical strengths elastic modulus capillary absorption drying shrinkage
Shuaicheng GUO, Qingli DAI, Jacob HILLER
《结构与土木工程前沿(英文)》 2018年 第12卷 第2期 页码 227-238 doi: 10.1007/s11709-017-0426-6
关键词: LTPP elastic modulus k-value IRI MEPDG
Vallarasu Manoharan SOUNTHARARAJAN, Dr. Anandan SIVAKUMAR
《结构与土木工程前沿(英文)》 2013年 第7卷 第4期 页码 429-445 doi: 10.1007/s11709-013-0226-6
关键词: fly ash pozzolanic index steam curing superplasticizer accelerator steel fibres elastic modulus
Tahir MAHMOOD, Sangarapillai KANAPATHIPILLAI, Mahiuddin CHOWDHURY
《机械工程前沿(英文)》 2013年 第8卷 第2期 页码 181-186 doi: 10.1007/s11465-013-0257-7
This paper demonstrates the application of a new multiaxial creep damage model developed by authors using stress traixiality to predict the failure time of a component made of 0.5%Cr-0.5%Mo-0.25%V low alloy steel. The model employs strain energy density and assumes that the uniaxial strain energy density of a component can be easily calculated and can be converted to multi-axial strain energy density by multiplying it to a function of stress trixiality which is a ratio of mean stress to equivalent stress. For comparison, an elastic-creep and elastic-plastic-creep finite element analysis (FEA) is performed to get multi-axial strain energy density of the component which is compared with the calculated strain energy density for both cases. The verification and application of the model are demonstrated by applying it to thin tube for which the experimental data are available. The predicted failure times by the model are compared with the experimental results. The results show that the proposed model is capable of predicting failure times of the component made of the above-mentioned material with an accuracy of 4.0%.
关键词: elastic-creep elastic-plastic-creep stress triaxiality life prediction pressure vessels finite element analysis (FEA)
Empirical models and design codes in prediction of modulus of elasticity of concrete
Behnam VAKHSHOURI, Shami NEJADI
《结构与土木工程前沿(英文)》 2019年 第13卷 第1期 页码 38-48 doi: 10.1007/s11709-018-0479-1
关键词: modulus of elasticity normal strength normal weight concrete empirical models design codes compressive strength density
Mohammed FARUQI, Gobishanker RAJASKANTHAN, Breanna BAILEY, Francisco AGUINIGA
《结构与土木工程前沿(英文)》 2022年 第16卷 第12期 页码 1653-1653 doi: 10.1007/s11709-019-0578-7
关键词: concrete fiber reinforced polymer E-modulus strength temperatures
Nonlinear dynamic analysis for elastic robotic arms
M. H. KORAYEM, H. N. RAHIMI
《机械工程前沿(英文)》 2011年 第6卷 第2期 页码 219-228 doi: 10.1007/s11465-011-0218-y
The aim of the paper is to analyze the nonlinear dynamics of robotic arms with elastic links and joints. The main contribution of the paper is the comparative assessment of assumed modes and finite element methods as more convenient approaches for computing the nonlinear dynamic of robotic systems. Numerical simulations comprising both methods are carried out and results are discussed. Hence, advantages and disadvantages of each method are illustrated. Then, adding the joint flexibility to the system is dealt with and the obtained model is demonstrated. Finally, a brief description of the optimal motion generation is presented and the simulation is carried out to investigate the role of robot dynamic modeling in the control of robots.
关键词: robotic arms elastic link elastic joint nonlinear dynamics optimal control
Senping WANG; Xiaolong LIU; Bo YUAN; Minjie SHI; Yanhui WEI
《结构与土木工程前沿(英文)》 2022年 第16卷 第9期 页码 1141-1152 doi: 10.1007/s11709-022-0866-5
关键词: torsional stiffness strength design elastic buckling space truss arches out-of-plane
Effects of elastic support on the dynamic behaviors of the wind turbine drive train
Shuaishuai WANG, Caichao ZHU, Chaosheng SONG, Huali HAN
《机械工程前沿(英文)》 2017年 第12卷 第3期 页码 348-356 doi: 10.1007/s11465-017-0420-7
The reliability and service life of wind turbines are influenced by the complex loading applied on the hub, especially amidst a poor external wind environment. A three-point elastic support, which includes the main bearing and two torque arms, was considered in this study. Based on the flexibilities of the planet carrier and the housing, a coupled dynamic model was developed for a wind turbine drive train. Then, the dynamic behaviors of the drive train for different elastic support parameters were computed and analyzed. Frequency response functions were used to examine how different elastic support parameters influence the dynamic behaviors of the drive train. Results showed that the elastic support parameters considerably influenced the dynamic behaviors of the wind turbine drive train. A large support stiffness of the torque arms decreased the dynamic response of the planet carrier and the main bearing, whereas a large support stiffness of the main bearing decreased the dynamic response of planet carrier while increasing that of the main bearing. The findings of this study provide the foundation for optimizing the elastic support stiffness of the wind turbine drive train.
关键词: wind turbine drive train elastic support dynamic behavior frequency response function
Frequencies of circular plate with concentric ring and elastic edge support
null
《机械工程前沿(英文)》 2014年 第9卷 第2期 页码 168-176 doi: 10.1007/s11465-014-0299-5
Exact solutions for the flexural vibrations of circular plates having elastic edge conditions along with rigid concentric ring support have been presented in this paper. Values of frequency parameter for the considered circular plate are computed for different sets of values of elastic rotational and translation restraints and the radius of internal rigid ring support. The results for the first three modes of plate vibrations are computed and are presented in tabular form. The effects of rotational and linear restraints and the radius of the rigid ring support on the vibration behavior of circular plates are studied over a wide range of non-dimensional parametric values. The values of the exact frequency parameter presented in this paper for varying values of restraint parameters and the radius of the rigid ring support can better serve in design and as benchmark solutions to validate the numerical methods obtained by using other methods of solution.
关键词: circular plate frequency elastic edge rigid ring mode switching
Nonlinear elastic model for compacted clay concrete interface
R. R. SHAKIR, Jungao ZHU
《结构与土木工程前沿(英文)》 2009年 第3卷 第2期 页码 187-194 doi: 10.1007/s11709-009-0033-2
关键词: interface modeling friction soil structure interface soil structure interaction simple shear test
标题 作者 时间 类型 操作
Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes
Daniel GAONA,Alfredo VALAREZO
期刊论文
Prediction of falling weight deflectometer parameters using hybrid model of genetic algorithm and adaptive neuro-fuzzy inference system
期刊论文
The stress relaxation of cement clinkers under high temperature
Xiufang WANG,Yiwang BAO,Xiaogen LIU,Yan QIU
期刊论文
Effect of natural pozzolan content on the properties of engineered cementitious composites as repair material
Said CHOUCHA, Amar BENYAHIA, Mohamed GHRICI, Mohamed Said MANSOUR
期刊论文
Investigation on the freeze-thaw damage to the jointed plain concrete pavement under different climate conditions
Shuaicheng GUO, Qingli DAI, Jacob HILLER
期刊论文
Accelerated engineering properties of high and low volume fly ash concretes reinforced with glued steel fibers
Vallarasu Manoharan SOUNTHARARAJAN, Dr. Anandan SIVAKUMAR
期刊论文
using strain energy density as a function of stress triaxiality under quasi-static loading employing elastic-creep& elastic-plastic-creep deformation
Tahir MAHMOOD, Sangarapillai KANAPATHIPILLAI, Mahiuddin CHOWDHURY
期刊论文
Empirical models and design codes in prediction of modulus of elasticity of concrete
Behnam VAKHSHOURI, Shami NEJADI
期刊论文
An improved design method to predict the E-modulus and strength of FRP composites at different temperatures
Mohammed FARUQI, Gobishanker RAJASKANTHAN, Breanna BAILEY, Francisco AGUINIGA
期刊论文
Out-of-plane elastic buckling load and strength design of space truss arch with a rectangular section
Senping WANG; Xiaolong LIU; Bo YUAN; Minjie SHI; Yanhui WEI
期刊论文
Effects of elastic support on the dynamic behaviors of the wind turbine drive train
Shuaishuai WANG, Caichao ZHU, Chaosheng SONG, Huali HAN
期刊论文