Surface strain fields of the designed compact tension(CT)specimens were investigated by digital image correlation(DIC)method.An integrative computer program was developed based on DIC algorithms to characterize the st...Surface strain fields of the designed compact tension(CT)specimens were investigated by digital image correlation(DIC)method.An integrative computer program was developed based on DIC algorithms to characterize the strain fields accurately and graphically.Strain distribution of the CT specimen was predicted by finite element method(FEM).Good agreement is observed between the surface strain fields measured by DIC and predicted by FEM,which reveals that the proposed method is practical and effective to determine the strain fields of CT specimens.Moreover,strain fields of the CT specimens with various compressive loads and notch diameters were studied by DIC.The experimental results can provide effective reference to usage of CT specimens in triaxial creep test by appropriately selecting specimen and experiment parameters.展开更多
A developed stereo particle image velocimetry(stereo-PIV) system was proposed to measure three-dimensional(3D) soil deformation around a laterally loaded pile in sand.The stereo-PIV technique extended 2D measurement t...A developed stereo particle image velocimetry(stereo-PIV) system was proposed to measure three-dimensional(3D) soil deformation around a laterally loaded pile in sand.The stereo-PIV technique extended 2D measurement to 3D based on a binocular vision model,where two cameras with a well geometrical setting were utilized to image the same object simultaneously.This system utilized two open software packages and some simple programs in MATLAB,which can easily be adjusted to meet user needs at a low cost.The failure planes form an angle with the horizontal line,which are measured at 27°-29°,approximately three-fourths of the frictional angle of soil.The edge of the strain wedge formed in front of the pile is an arc,which is slightly different from the straight line reported in the literature.The active and passive influence zones are about twice and six times of the diameter of the pile,respectively.The test demonstrates the good performance and feasibility of this stereo-PIV system for more advanced geotechnical testing.展开更多
岩石-混凝土界面是工程结构的薄弱环节,对结构整体的强度和稳定性有重要影响。为反映岩-混界面天然粗糙状态,基于内聚力模型(cohesive zone model,简称CZM),建立了具有随机生成粗糙界面的岩石-混凝土复合巴西圆盘试件数值模型,通过不同...岩石-混凝土界面是工程结构的薄弱环节,对结构整体的强度和稳定性有重要影响。为反映岩-混界面天然粗糙状态,基于内聚力模型(cohesive zone model,简称CZM),建立了具有随机生成粗糙界面的岩石-混凝土复合巴西圆盘试件数值模型,通过不同加载角度下的巴西劈裂物理试验验证了该方法的可靠性,并探究了界面粗糙度、加载角度对试件峰值荷载和破坏特征的影响。结果表明:不同加载角度下,试件存在3种典型破坏模式:界面黏结破坏、复合破坏、双材料拉伸开裂破坏;加载角度对试件力学行为的影响以70°为界,加载角度小于70°时影响显著,大于70°后影响不显著;界面粗糙度的影响随加载角度的不同有较大差异,当加载角度在15°~65°范围内,提高界面粗糙度可显著提高试件峰值荷载,增强岩-混结构的承载能力;界面处应力状态的差异决定了试件破坏模式的不同,但粗糙的界面可以增强混凝土与岩石之间的黏结和互锁效应,对试件破坏模式产生影响。研究结果将加深对岩石-混凝土界面破坏机制的认识,对工程建设具有指导意义。展开更多
基金Projects(51575347,51405297,51204107)supported by the National Natural Science Foundation of China
文摘Surface strain fields of the designed compact tension(CT)specimens were investigated by digital image correlation(DIC)method.An integrative computer program was developed based on DIC algorithms to characterize the strain fields accurately and graphically.Strain distribution of the CT specimen was predicted by finite element method(FEM).Good agreement is observed between the surface strain fields measured by DIC and predicted by FEM,which reveals that the proposed method is practical and effective to determine the strain fields of CT specimens.Moreover,strain fields of the CT specimens with various compressive loads and notch diameters were studied by DIC.The experimental results can provide effective reference to usage of CT specimens in triaxial creep test by appropriately selecting specimen and experiment parameters.
基金Project(104244) supported by the Natural Sciences and Engineering Research Council of Canada
文摘A developed stereo particle image velocimetry(stereo-PIV) system was proposed to measure three-dimensional(3D) soil deformation around a laterally loaded pile in sand.The stereo-PIV technique extended 2D measurement to 3D based on a binocular vision model,where two cameras with a well geometrical setting were utilized to image the same object simultaneously.This system utilized two open software packages and some simple programs in MATLAB,which can easily be adjusted to meet user needs at a low cost.The failure planes form an angle with the horizontal line,which are measured at 27°-29°,approximately three-fourths of the frictional angle of soil.The edge of the strain wedge formed in front of the pile is an arc,which is slightly different from the straight line reported in the literature.The active and passive influence zones are about twice and six times of the diameter of the pile,respectively.The test demonstrates the good performance and feasibility of this stereo-PIV system for more advanced geotechnical testing.
文摘岩石-混凝土界面是工程结构的薄弱环节,对结构整体的强度和稳定性有重要影响。为反映岩-混界面天然粗糙状态,基于内聚力模型(cohesive zone model,简称CZM),建立了具有随机生成粗糙界面的岩石-混凝土复合巴西圆盘试件数值模型,通过不同加载角度下的巴西劈裂物理试验验证了该方法的可靠性,并探究了界面粗糙度、加载角度对试件峰值荷载和破坏特征的影响。结果表明:不同加载角度下,试件存在3种典型破坏模式:界面黏结破坏、复合破坏、双材料拉伸开裂破坏;加载角度对试件力学行为的影响以70°为界,加载角度小于70°时影响显著,大于70°后影响不显著;界面粗糙度的影响随加载角度的不同有较大差异,当加载角度在15°~65°范围内,提高界面粗糙度可显著提高试件峰值荷载,增强岩-混结构的承载能力;界面处应力状态的差异决定了试件破坏模式的不同,但粗糙的界面可以增强混凝土与岩石之间的黏结和互锁效应,对试件破坏模式产生影响。研究结果将加深对岩石-混凝土界面破坏机制的认识,对工程建设具有指导意义。
