ABSTRACT

The paper aims to evaluate the effectiveness of both distributed fibre optics sensors (DFOs), and fibre Bragg grating sensors (FBGs) to acquire an accurate measurement of the flexural strain of foamed bitumen stabilised (FBS) beams and to assess the material behaviour under both static and dynamic loading conditions. The beams were equipped with DFOs, FBGs and a linear variable differential transformer (LVDT) to perform the static and dynamic flexural tests using a four-point bending apparatus. The initial plastic flexural strain progression of both top and bottom faces of the beam specimen under different test conditions, including different load pulse shapes and rest periods were evaluated. The results revealed that both haversine-upward and haversine-downward pulse shapes lead to a significant amount of plastic flexural strain compared to that evolved through sinusoidal pulse shapes. However, the plastic flexural strain under haversine pulse shapes can be minimised by introducing a rest period at certain cycle intervals. Further, the flexural strain profile captured by DFOs during the static and dynamic flexural tests indicated the capacity of DFOs to detect cracks initiation and propagation.

摘要

本文旨在评估分布式光纤传感器 (DFO) 和光纤布拉格光栅传感器 (FBG) 的有效性，以准确测量泡沫沥青稳定 (FBS) 梁的弯曲应变，并评估两种情况下的材料行为。静态和动态加载条件。梁配备了 DFO、FBG 和线性可变差动变压器 (LVDT)，以使用四点弯曲设备进行静态和动态弯曲测试。评估了在不同的测试条件下，包括不同的负载脉冲形状和休息时间，梁试样的顶面和底面的初始塑性弯曲应变进程。结果表明，与通过正弦脉冲形状演变的情况相比，向上和向下的半正弦脉冲形状都会导致大量的塑性弯曲应变。然而，可以通过在某些周期间隔引入休息期来最小化在正弦脉冲形状下的塑性弯曲应变。此外，DFO 在静态和动态弯曲测试期间捕获的弯曲应变曲线表明 DFO 检测裂纹萌生和扩展的能力。