Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar ha...Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.展开更多
In the present paper,a homogenization-based two-scale FEM-FEM model is developed to simulate compactions of visco-plastic granular assemblies.The granular structure consisting of two-dimensional grains is modeled by t...In the present paper,a homogenization-based two-scale FEM-FEM model is developed to simulate compactions of visco-plastic granular assemblies.The granular structure consisting of two-dimensional grains is modeled by the microscopic finite element method at the small-scale level,and the homogenized viscous assembly is analyzed by the macroscopic finite element method at large-scale level.The link between scales is made using a computational homogenization method.The two-scale FEM-FEM model is developed in which each particle is treated individually with the appropriate constitutive relations obtained from a representative volume element,kinematic conditions,contact constraints,and elimination of overlap satisfied for every particle.The method could be used in a variety of problems that can be represented using granular media.展开更多
基金sponsored by the National Natural Science Foundation of China (Grant Nos.52178299 and 51325802).
文摘Extrudability and constructability are two important,yet contradictory issues pertaining to the construction of three-dimensional(3D)printing concrete.Extrudability is easily achieved when 3D printing cement mortar has a high water content and low cohesion,but the printed structure is easily collapsible.However,a 3D printing cement mortar with a low water content and high cohesion has a relatively stable printed structure although the cement mortar might not be extrudable.This study proposes a particle-based method to simulate 3D printing mortar extrusion and construction as an overall planning tool for building design.First,a discrete element model with time-varying liquid bridge forces is developed to investigate the microscopic effects of these forces on global rheological properties.Next,a series of numerical simulations relevant to 3D printable mortar extrudability and constructability are carried out.The study demonstrates that the effects of time-varying liquid bridge forces on rheological properties and the resulting extrudability and constructability of 3D printing mortar are considerable.Furthermore,an optimized region that satisfies both the extrusion and construction requirements is provided for 3D printing industry as a reference.
基金This work was supported by National Natural Science Foundation of China(Grant No.10972162).
文摘In the present paper,a homogenization-based two-scale FEM-FEM model is developed to simulate compactions of visco-plastic granular assemblies.The granular structure consisting of two-dimensional grains is modeled by the microscopic finite element method at the small-scale level,and the homogenized viscous assembly is analyzed by the macroscopic finite element method at large-scale level.The link between scales is made using a computational homogenization method.The two-scale FEM-FEM model is developed in which each particle is treated individually with the appropriate constitutive relations obtained from a representative volume element,kinematic conditions,contact constraints,and elimination of overlap satisfied for every particle.The method could be used in a variety of problems that can be represented using granular media.
