The quality and geometry conformity of 3D concrete printing are the two major concerns facing autonomous construction. To investigate the geometry of printed concrete and optimize the printing strategy, the reproducing kernel particle method (RKPM) was developed and implemented for the first time to describe the flow of fresh concrete and simulate the process of 3D printing. The proposed novel numerical simulation method is associated with a Bingham constitutive model, which was determined by a rotational rheometer. Physical slump tests were performed at various resting times to investigate the time-dependent behavior of concrete. An experimental parametric study of the geometry of a single-layer printed concrete was also conducted at various printing speeds and nozzle heights. Multi-layer printing cases were performed to investigate the cross-sectional deformation over the printed layers. The simulated values of slump over time compared well with the experimental measurements. As such, the proposed RKPM ability to capture time-dependent concrete behavior has been validated. The simulations based on the initially verified RKPM method can yield precise geometry predictions of a single- and multi-layer printed concrete, proving a wide range of application scenarios of the novel RKPM modeling approach.

中文翻译：

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使用再生核粒子方法通过 3D 打印模拟混凝土沉积

3D混凝土打印的质量和几何一致性是自主建造面临的两个主要问题。为了研究打印混凝土的几何形状并优化打印策略，首次开发并实施了再生核粒子法（RKPM）来描述新拌混凝土的流动并模拟3D打印过程。所提出的新颖数值模拟方法与宾厄姆本构模型相关，该模型由旋转流变仪确定。在不同的休息时间进行物理坍落度测试，以研究混凝土的时间依赖性行为。还在不同的打印速度和喷嘴高度下对单层打印混凝土的几何形状进行了实验参数研究。进行多层印刷案例以研究印刷层上的横截面变形。随时间推移的坍落度模拟值与实验测量值相比较。因此，所提出的 RKPM 捕获时间相关的具体行为的能力已经得到验证。基于初步验证的 RKPM 方法的模拟可以对单层和多层打印混凝土进行精确的几何预测，证明了新型 RKPM 建模方法的广泛应用场景。