The comprehensive tire building and shaping processes are investigated through the finite element method(FEM)in this article.The mechanical properties of the uncured rubber from different tire components are investiga...The comprehensive tire building and shaping processes are investigated through the finite element method(FEM)in this article.The mechanical properties of the uncured rubber from different tire components are investigated through cyclic loading-unloading experiments under different strain rates.Based on the experiments,an elastoviscoplastic constitutive model is adopted to describe themechanical behaviors of the uncured rubber.The distinct mechanical properties,including the stress level,hysteresis and residual strain,of the uncured rubber can all be well characterized.The whole tire building process(including component winding,rubber bladder inflation,component stitching and carcass band folding-back)and the shaping process are simulated using this constitutive model.The simulated green tire profile is in good agreement with the actual profile obtained through 3D scanning.The deformation and stress of the rubber components and the cord reinforcements during production can be obtained fromthe FE simulation,which is helpful for judging the rationality of the tire construction design.Finally,the influence of the parameter“drum width”is investigated,and the simulated result is found to be consistent with the experimental observations,which verifies the effectiveness of the simulation.The established simulation strategy provides some guiding significance for the improvement of tire design parameters and the elimination of tire production defects.展开更多
The finite element bearing deformation simulation was implemented on 11.00R22.5 retreaded tires by ANSYS software in the paper in order to further clarify the bearing deformation characteristics of retreaded tires and...The finite element bearing deformation simulation was implemented on 11.00R22.5 retreaded tires by ANSYS software in the paper in order to further clarify the bearing deformation characteristics of retreaded tires and improve the performance of retreaded tires effectively.The characteristic laws of bearing radial deformation and bearing lateral deformation of retreaded tire and new tires of the same model under different working conditions were obtained through load deformation tests.The radial deformation calculation results,simulation results and measured results of retreaded tires were comparatively analyzed.The calculation formula of bearing radial deformation of retreaded tires was proposed based on the linear regression principle.The difference of bearing deformation characteristics and ground area characteristics of retreaded tires and new tires were comparatively analyzed.The results showed that the radial and lateral deformation of retreaded tires and new tires is increased with the increase of radial load when the tire pressure was constant,and the increase trend is approximately linear.The radial stiffness of retreaded tires is similar to that of new tires under certain tire pressure and low load.The radial stiffness of retreaded tires is larger than that of new tires,and the stiffness difference is increased with the increasing of load under constant tire pressure and high load.Rubber aging phenomenon in retreaded tire carcass have an impact on the bearing deformation characteristics of retreaded tires,thereby producing great impact on the remaining service life of retreaded tires.展开更多
目的 探讨三级谵妄护理管理流程在神经内科重症监护室(neurology intensive care unit,NICU)急性脑卒中患者中的应用效果。方法 选择2021年5月至9月本院NICU收治的50例急性脑卒中患者作为研究对象并设为对照组,采取NICU预防谵妄的常规...目的 探讨三级谵妄护理管理流程在神经内科重症监护室(neurology intensive care unit,NICU)急性脑卒中患者中的应用效果。方法 选择2021年5月至9月本院NICU收治的50例急性脑卒中患者作为研究对象并设为对照组,采取NICU预防谵妄的常规护理措施;选择2021年12月至2022年4月收治NICU的50例急性脑卒中患者作为研究对象并设为试验组,试验组患者在对照组基础上实施三级谵妄护理管理流程,比较两组患者ICU谵妄(delirium in the intensive care unit,DICU)发生率、DICU持续时间、NICU住院时间、谵妄相关不良事件发生率;比较干预前后两组患者的谵妄水平和认知功能改善情况。结果 试验组患者DICU发生率较对照组低,两组比较,差异具有统计学意义(P<0.05)。试验组患者DICU持续时间、NICU住院时间较对照组短,谵妄相关不良事件发生率较对照组低;干预后试验组患者重症监护谵妄筛查量表(intensive care delirium screening checklist,ICDSC)评分低于对照组;试验组患者认知功能评分干预前后差值高于对照组,两组比较,差异有统计学意义(均P<0.05)。结论 在NICU急性脑卒中患者中实施三级谵妄护理管理流程可减少患者谵妄的发生,改善患者认知功能,缩短NICU住院时间,降低护理安全风险。展开更多
基金funded by the NationalNatural Science Foundation of China (Nos.11902229,11502181)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos.XDB22040502,XDC06030200).
文摘The comprehensive tire building and shaping processes are investigated through the finite element method(FEM)in this article.The mechanical properties of the uncured rubber from different tire components are investigated through cyclic loading-unloading experiments under different strain rates.Based on the experiments,an elastoviscoplastic constitutive model is adopted to describe themechanical behaviors of the uncured rubber.The distinct mechanical properties,including the stress level,hysteresis and residual strain,of the uncured rubber can all be well characterized.The whole tire building process(including component winding,rubber bladder inflation,component stitching and carcass band folding-back)and the shaping process are simulated using this constitutive model.The simulated green tire profile is in good agreement with the actual profile obtained through 3D scanning.The deformation and stress of the rubber components and the cord reinforcements during production can be obtained fromthe FE simulation,which is helpful for judging the rationality of the tire construction design.Finally,the influence of the parameter“drum width”is investigated,and the simulated result is found to be consistent with the experimental observations,which verifies the effectiveness of the simulation.The established simulation strategy provides some guiding significance for the improvement of tire design parameters and the elimination of tire production defects.
基金This study was supported by Basic Scientific Research Operating Expense Funding Project of Provincial Univeristies in Heilongjiang Province(2018CX07)Heilongjiang Institute of Engineering Ph.D.Fund.(2016BJ02).
文摘The finite element bearing deformation simulation was implemented on 11.00R22.5 retreaded tires by ANSYS software in the paper in order to further clarify the bearing deformation characteristics of retreaded tires and improve the performance of retreaded tires effectively.The characteristic laws of bearing radial deformation and bearing lateral deformation of retreaded tire and new tires of the same model under different working conditions were obtained through load deformation tests.The radial deformation calculation results,simulation results and measured results of retreaded tires were comparatively analyzed.The calculation formula of bearing radial deformation of retreaded tires was proposed based on the linear regression principle.The difference of bearing deformation characteristics and ground area characteristics of retreaded tires and new tires were comparatively analyzed.The results showed that the radial and lateral deformation of retreaded tires and new tires is increased with the increase of radial load when the tire pressure was constant,and the increase trend is approximately linear.The radial stiffness of retreaded tires is similar to that of new tires under certain tire pressure and low load.The radial stiffness of retreaded tires is larger than that of new tires,and the stiffness difference is increased with the increasing of load under constant tire pressure and high load.Rubber aging phenomenon in retreaded tire carcass have an impact on the bearing deformation characteristics of retreaded tires,thereby producing great impact on the remaining service life of retreaded tires.
文摘目的 探讨三级谵妄护理管理流程在神经内科重症监护室(neurology intensive care unit,NICU)急性脑卒中患者中的应用效果。方法 选择2021年5月至9月本院NICU收治的50例急性脑卒中患者作为研究对象并设为对照组,采取NICU预防谵妄的常规护理措施;选择2021年12月至2022年4月收治NICU的50例急性脑卒中患者作为研究对象并设为试验组,试验组患者在对照组基础上实施三级谵妄护理管理流程,比较两组患者ICU谵妄(delirium in the intensive care unit,DICU)发生率、DICU持续时间、NICU住院时间、谵妄相关不良事件发生率;比较干预前后两组患者的谵妄水平和认知功能改善情况。结果 试验组患者DICU发生率较对照组低,两组比较,差异具有统计学意义(P<0.05)。试验组患者DICU持续时间、NICU住院时间较对照组短,谵妄相关不良事件发生率较对照组低;干预后试验组患者重症监护谵妄筛查量表(intensive care delirium screening checklist,ICDSC)评分低于对照组;试验组患者认知功能评分干预前后差值高于对照组,两组比较,差异有统计学意义(均P<0.05)。结论 在NICU急性脑卒中患者中实施三级谵妄护理管理流程可减少患者谵妄的发生,改善患者认知功能,缩短NICU住院时间,降低护理安全风险。
