Fibre-reinforced polymer (FRP) bars are used in concrete structural members to tackle the corrosion problem of steel bars. However, the brittle rupture of FRP bars results in relatively low ductility of such concrete members. This paper numerically investigates the feasibility of using compression yielding (CY) block to enhance the ductility of FRP bar reinforced concrete beams. A finite element model is developed to study the behaviour of beam adopting the CY block, followed by a parametric analysis on the effects of material properties and geometry of the CY block. The results indicate that the adoption of CY block changes the failure mode of the beam from brittle concrete crushing to ductile compression yielding, increasing both the loading capacity and ductility of the beam. Increasing the compressive yield strength of the CY block can effectively increase the loading capacity but decrease the ductility of beams. A higher compressive ultimate strength of the CY block also increases the loading capacity but has limited effect on the beam ductility. In addition, the beam ductility can be increased by reducing the yielding and ultimate strains of the CY block, while the loading capacity can be enhanced by higher yielding strain or lower ultimate strain. It is revealed that sufficient height of the CY block is required to prevent concrete crushing in the compression zone, and an increase in CY block height improves the beam ductility. The CY block length should cover at least the pure bending zone when the section with the block has higher flexural capacity than that without the block, otherwise the length can be controlled as the theoretical plastic hinge length.

中文翻译：

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受压屈服块FRP钢筋混凝土梁弯曲性能数值研究

纤维增强聚合物（FRP）钢筋用于混凝土结构构件，以解决钢筋的腐蚀问题。然而，FRP筋的脆性断裂导致此类混凝土构件的延展性相对较低。本文数值研究了使用压缩屈服（CY）块来增强 FRP 钢筋混凝土梁延性的可行性。开发了有限元模型来研究采用 CY 块的梁的行为，然后对 CY 块的材料特性和几何形状的影响进行参数分析。结果表明，CY块的采用改变了梁的破坏模式，由脆性混凝土破碎转变为延性压缩屈服，提高了梁的承载能力和延性。提高CY块的抗压屈服强度可以有效提高梁的承载能力，但会降低梁的延性。 CY 块较高的抗压极限强度也增加了承载能力，但对梁延展性的影响有限。此外，可以通过降低CY块的屈服应变和极限应变来提高梁的延性，而通过提高屈服应变或降低极限应变来提高承载能力。结果表明，需要足够的CY块高度来防止受压区混凝土破碎，并且CY块高度的增加提高了梁的延性。当有块的截面比无块的截面具有更高的抗弯承载力时，CY块的长度应至少覆盖纯弯曲区，否则长度可控制为理论塑性铰长度。