祝贺张昱铭的论文《Improving the shear design of steel-bar reinforced ultra high performance fibre reinforced concrete beams using mesoscale modelling》在Advances in Structural Engineering期刊上发表！

论文链接：https://journals.sagepub.com/doi/abs/10.1177/13694332221137174

Improving the shear design of steel-bar reinforced ultra high performance fibre reinforced concrete beams using mesoscale modelling

Yuming Zhang, Zhenjun Yang, Hui Zhang, Neil Tsang, Xiaoxian Zhang

Abstract：Understanding the failure mechanisms of steel-bar reinforced ultra high performance fibre reinforced concrete (UHPFRC) beams is crucial to improving their design but challenging because of the contrast between beam size and fibre size. We develop a 2D mesoscale finite element model with the fibres explicitly resolved to bridge this gap by simulating the damaging and fracturing processes of the beams. To make fibre distribution in the model mechanically representative, we propose a method to project the fibres from 3D to 2D. The continuum damaged plasticity model is used as the constitutive law for the UHPC matrix, and the zero-thickness cohesive elements with softening constitutive law are used to model the nonlinear bond-slip behaviour of the fibre- and bar-matrix interfaces. The models are validated against experimental data obtained from 3 and 4-point loading tests by comparing the simulated and measured fracturing processes, crack patterns and the load-displacement curves. The validated models are then used to analyse the sensitivity of the shear strength of the beams to fibre content, shear span-to-depth ratio, as well as shear and longitudinal reinforcement ratios in the beam, from which a shear strength equation is proposed to improve the design of reinforced UHPFRC beams. The improvement of the new equation over the AFGC equation is demonstrated against experimental data measured from 32 beams with various material properties.

摘要：理解钢筋增强超高性能纤维增强混凝土(UHPFRC)梁的破坏机理对设计改进至关重要，但梁和纤维之间的尺寸差异会给模拟带来困难。因此，我们开发了一种二维中尺度有限元模型，通过模拟梁的破坏和压裂过程，来明确解决这一问题。为了使模型中的纤维分布具有机械代表性，我们提出了一种将纤维从3D投影到2D的方法。采用连续介质损伤塑性模型作为UHPC基体的本构规律，采用具有软化本构规律的零厚度内聚单元来模拟纤维-和棒材-基体界面的非线性粘结滑移行为。通过对比3点和4点加载试验中模拟和实测的压裂过程、裂缝形态和载荷-位移曲线，验证了模型的正确性。然后，利用验证的模型分析了梁的抗剪强度对纤维含量、抗剪跨深比以及梁的抗剪和纵向配筋比的敏感性，由此提出一个抗剪强度方程，以改进UHPFRC加筋梁的设计。通过对32个具有不同材料性质的梁体实验数据的分析，证明了新方程基于AFGC方程的改进。

图1 纤维从3D到2D的投影

图2 例1中典型的开裂过程和模式模拟

图3 例2中模拟梁A失效模式的截面视图

本研究由国家自然科学基金(No. 52173300和51974202)、湖北省重点研发计划(No. 2020BAB052)和中德研究促进中心(No. 2020BAB052)资助。m - 0172)。

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study is funded by National Natural Science Foundation of China (No. 52173300 and 51974202), Key Research and Development Programme of Hubei Province (No. 2020BAB052) and Sino- German Center for Research Promotion (Mobility Programme No. M-0172).