This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tigh...This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running.Mechanical tests were conducted using 16 weights,and various statistical analyses,including linear regression,Bland-Altman plots,coefficient of variation,and intraclass correlation coefficient,were performed to assess the system’s validity.Fifteen male amateur runners participated in the study,and three conditions(loose,comfortable,and tight)were measured during an upright stance.The system utilized VICON motion systems,a Kistler force plate,and a Photoelectric gate speed measurement system.Results showed a linear relationship between voltage and load at the three sensors(R2≥0.9997).Bland-Altman plots demonstrated 95%prediction intervals within±1.96SD from zero for all sensors.The average coefficient of variation for each sensor was less than 0.38%.Intraclass correlation coefficient values were larger than 0.999(p<0.0001)for each sensor.The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight.The rear shoelace had the highest tension force.The study also found that shoelace tension varied throughout the gait cycle during running.Overall,this research provides a novel and validated method for measuring shoelace tensile stress,which has implications for developing automatic shoelace fastening systems.展开更多
高强螺栓作为关键零部件,广泛应用于悬索桥、风电塔筒等重要结构中,其安装质量对整体结构的稳定性和安全性具有至关重要的影响。然而,传统的扭矩法难以准确测量螺栓的轴向预紧力,从而难以有效评估结构的稳定性。为解决这一问题,基于声...高强螺栓作为关键零部件,广泛应用于悬索桥、风电塔筒等重要结构中,其安装质量对整体结构的稳定性和安全性具有至关重要的影响。然而,传统的扭矩法难以准确测量螺栓的轴向预紧力,从而难以有效评估结构的稳定性。为解决这一问题,基于声弹性效应,设计了高压激励和压控增益等电路,研制了一套螺栓轴力检测系统。系统通过激励压电传感器接收回波信号,并采用互相关算法计算渡越时间差以表征螺栓的应力状态,最后对风电螺栓进行了应力-渡越时间标定实验及超声法与扭矩法的对比实验。实验结果表明,当螺栓轴向预紧力达到其额定值的40%时,该系统的应力测量误差率≤2.81%,且分辨率可达0.2507 k N,能够有效满足螺栓轴向预紧力的测量要求。与传统扭矩法相比,超声法在螺栓服役状态下的应力测量误差控制与分辨率均具有显著优势,为工业领域关键部件的应力测量提供了可靠的技术方案。展开更多
文摘This study investigated the validity and sensitivity of a custom-made shoelace tensile testing system.The aim was to analyze the distribution pattern of shoelace tension in different positions and under different tightness levels during running.Mechanical tests were conducted using 16 weights,and various statistical analyses,including linear regression,Bland-Altman plots,coefficient of variation,and intraclass correlation coefficient,were performed to assess the system’s validity.Fifteen male amateur runners participated in the study,and three conditions(loose,comfortable,and tight)were measured during an upright stance.The system utilized VICON motion systems,a Kistler force plate,and a Photoelectric gate speed measurement system.Results showed a linear relationship between voltage and load at the three sensors(R2≥0.9997).Bland-Altman plots demonstrated 95%prediction intervals within±1.96SD from zero for all sensors.The average coefficient of variation for each sensor was less than 0.38%.Intraclass correlation coefficient values were larger than 0.999(p<0.0001)for each sensor.The peak tension of the front shoelace was greater than that of the front and middle when the shoelace was loose and tight.The rear shoelace had the highest tension force.The study also found that shoelace tension varied throughout the gait cycle during running.Overall,this research provides a novel and validated method for measuring shoelace tensile stress,which has implications for developing automatic shoelace fastening systems.
文摘高强螺栓作为关键零部件,广泛应用于悬索桥、风电塔筒等重要结构中,其安装质量对整体结构的稳定性和安全性具有至关重要的影响。然而,传统的扭矩法难以准确测量螺栓的轴向预紧力,从而难以有效评估结构的稳定性。为解决这一问题,基于声弹性效应,设计了高压激励和压控增益等电路,研制了一套螺栓轴力检测系统。系统通过激励压电传感器接收回波信号,并采用互相关算法计算渡越时间差以表征螺栓的应力状态,最后对风电螺栓进行了应力-渡越时间标定实验及超声法与扭矩法的对比实验。实验结果表明,当螺栓轴向预紧力达到其额定值的40%时,该系统的应力测量误差率≤2.81%,且分辨率可达0.2507 k N,能够有效满足螺栓轴向预紧力的测量要求。与传统扭矩法相比,超声法在螺栓服役状态下的应力测量误差控制与分辨率均具有显著优势,为工业领域关键部件的应力测量提供了可靠的技术方案。
