3D打印高延性水泥基复合材料的单轴受拉和受压行为

Uniaxial Tensile and Compressive Stress-Strain Behavior of 3D printed Engineered Cementitious Composites

为探究不同成型方式对聚乙烯(PE)高延性水泥基复合材料(ECC)单轴受拉及受压力学性能的影响,基于现浇和3D打印2种成型方式,测试了现浇ECC及打印ECC的轴心受拉及轴心抗压应力-应变关系曲线。结果表明:3D打印成型方式使得试件的极限拉伸强度略有降低,拉伸延性却有大幅提升。纤维体积掺量不变的条件下,6 mm和12 mm纤维的混杂不会明显改变ECC的单轴抗压强度。打印ECC的抗压强度表现出明显的各向异性,其抗压强度相当于现浇ECC的60%〜70%,Z方向强度最高,义方向次之,X方向强度最低。打印ECC弹性模量无明显变化规律,义和F方向的Poisson比比现浇ECC高。建立了适用于现浇ECC和3D打印ECC的单轴受压应力•应变本构关系模型,并将模型与试验结果对比,验证该模型的准确性,为3D打印ECC构件和结构的计算分析提供了理论依据。

In order to investigate the influence of fabrication method on the uniaxial tensile and compressive properties of polyethylene(PE)reinforced engineered cementitious composites(ECC),the axial tensile and axial compressive stress-strain curves of cast-in-place ECC and 3D printed ECC were measured.The results show that the ultimate tensile strength of the printed specimen decreases slightly,while the tensile ductility greatly improves.The uniaxial compressive strength of ECC is not affected by mixing 6 mm and 12 mm PE fibers in ECC at a constant fiber volume content.The compressive strength of printed ECC is 60%-70%of that of cast-in-place ECC.The maximum compressive strength in z-direction and followed by x-and v-direction.The elastic modulus of printed specimen has a slight change.Moreover,the Poisson ratio in.v-and v-directions is greater than that of cast-in-place ECC.A uniaxial compression stress-strain constitutive model suitable for cast-in-place ECC and printed ECC was established,and the accuracy of the model was verified by comparing with the measurement results.The model provides a theoretical basis for the calculation and analysis of 3D printed ECC components and structures.