【作者】 邹定华；

【导师】 马保国；

【作者基本信息】 武汉理工大学 ， 建筑材料与工程， 2009， 博士

【摘要】 交通事故是影响现代道路交通系统效率的重要因素。随着经济和社会的发展,车辆数量的持续增长不断使得道路交通系统负荷增大,同时增大了交通事故发展的概率。在高速公路和城市交通关键枢纽区域,交通事故的发生降低了整个道路系统的通行能力,甚至导致交通的中断,因此在这些区域的交通事故控制尤为重要。交通事故的发生受到多个因素的影响,包括驾驶员的精神状态、车速、行驶路径、天气条件、车重、道路交通状况等。对于行驶中的车辆,可通过监测车辆辆行驶状态、车重、道路交通状况,根据路段的具体情况（路段弯直、坡度、路面材料种类等）和天气条件,通过控制车辆速度及行驶路线降低交通事故发生概率。本文依托国家“863”计划项目（2006AA11Z117）,从交通事故控制出发,设计了以压电陶瓷为敏感材料、可同时测量车辆行驶状态、车辆结构参数及车重的智能交通传感器,并从智能交通传感器功能及其工作环境出发,研究开发了传感器敏感材料、敏感材料封装片及保护材料,在此基础上制备传感器,研究了各种条件下传感器的输出。主要工作及成果如下:1.采用Cr³⁺掺杂、K⁺低温烧成的技术路线,结合热处理的方法降低压电陶瓷老化率的烧成温度,制备出烧成温度为960℃、10倍时间老化率为1.18%的敏感材料。（1）Cr³⁺对敏感材料电畴畴壁有钉扎作用,使其难以被极化,但在Cr₂O₃掺量小于0.3%时对敏感材料烧结有促进作用,敏感材料的压电常数随掺量增大升高;而在掺量大于0.3%时限制陶瓷晶体的生长,导致敏感材料内晶界面积过大,晶体内电偶极子的运动困难,自发极化作用降低,敏感材料的压电常数随掺量增大降低,因此其最佳掺量为0.3%。（2）KCl在770℃熔解形成熔体,促进敏感材料的烧成,使其烧成温度大幅度降低。同时,K⁺取代形成O空位使敏感材料10倍时间老化率增大,增大热处理后压电陶瓷压电性能的稳定性。（3）热处理大大提高敏感材料压电性能的稳定性。采用合适的热处理工艺,可敏感材料的10倍时间老化率小于1.8%。2.以离子掺杂和低温液相烧结相结合的方法,降低95氧化铝陶瓷的烧结温度,制备出烧结温度为1550℃,吸水率接近于零,体积电阻率大于9×10¹²Ω·m的敏感材料封装片。（1）采用离子掺杂烧结和低温液相烧结结合的方法可大大降低氧化铝封装片的烧结温度,且材料的吸水率、化学侵蚀下的质量损失均较低,体积电阻率高。（2）单一的TiO₂掺杂烧结可降低烧结温度,但材料的吸水率较高,体积电阻率相对较低,较高温度下烧成的封装片力学性能因晶粒异常长大而大幅度下降。单一的低温液相烧结封装片性能受配比影响大,且材料的吸水率高,体积电阻率低。（3）封装片的微观结构、密度、吸水率、弯曲强度随保温时间的延长变化较小;酸侵蚀和水侵蚀下的质量损失率基本不变,碱侵蚀下的质量损失随保温时间延长先急剧下降,其后基本没有变化,而体积电阻率随保温时间延长先急剧增大,其后平缓增大。3.研究了传感器保护材料的力学性能及抗冻性能、抗氯离子侵蚀性能及耐酸侵蚀性能等耐久性,提出保护材料弯曲韧性评价方法。（1）聚合物粗纤维可提高混凝土的力学性能,其增强效果与钢纤维相当。由于聚合物粗纤维的弹性模量为钢纤维的1/7-1/9,聚合物粗纤维对混凝土的增强作用更多地作用在混凝土破坏后。（2）由于聚合物粗纤维存在“挠度回弹”的现象,已有的混凝土韧性评价方法不适用于聚合物粗纤维混凝土,可采用“挠度回弹点”应力和应力峰值点应力比值和应力峰值点挠度与“挠度回弹点”挠度比值的均方值作为评价指标。（3）聚合物粗纤维可有效提高混凝土的抗冻性能,而由于弹性模量低,对混凝土抗冻性能的增强效果低于钢纤维,而其抗氯离子侵蚀性能和耐酸侵蚀性能均高于相同掺量的钢纤维混凝土。4.制备了以PZT型压电陶瓷和PLMN型压电陶瓷为敏感材料的智能交通传感器,研究了两种传感器在不同应力水平下、不同加载时间、不同温度和疲劳荷载作用下的输出特性。（1）以PZT型压电陶瓷为敏感材料的智能交通传感器有较宽的线性范围,在0.1MPa-2MPa范围内压力与输出的线性关系好;而以PLMN型压陶瓷为敏感材料的智能交通传感器的线性范围窄,在0.1MPa-1.5MPa范围内压力与输出存在线性关系,但其线性关系置信度低于以PZT型型压电陶瓷为敏感材料的交通传感器,而在1.5MPa以上压力与输出不存在线性关系（2）以PZT型压电陶瓷为敏感材料的智能交通传感器在加载时间小于0.1s时其输出-压力比受加载时间的影响较小,而在加载时间大于0.1s时输出-压力比随时间的延长减小;在相同加载时间下,输出-压力比随压力的减小而减小。以PLMN型压陶瓷为敏感材料的智能交通传感器的输出-压力比随加载时间的增大而减小,而压力-荷载比受压力大小的影响不规律。（3）在-20℃-60℃范围内,以PZT型和PLMN压电陶瓷为敏感材料的智能交通传感器的输出随温度上升先减小后增大,输出与压力之间的线性关系随温上升而变差。（4）以PZT型和PLMN压电陶瓷为敏感材料的智能交通传感器的输出基本不受疲劳荷载的影响,加载前与50万次疲劳荷后、100万次疲劳荷载后的输出变化很小。更多还原

【Abstract】 Traffic accident decreases efficiency of road traffic system.With development of Economic and social,continuous increasement of vehicle overload the road traffic system.That lead to high probability of traffic accidnet.Moreover,traffic accidents occun-in highway or key road section of urban road system may weaken traffic capacity of them,or cause the interruption of traffic.Reducing traffic accident is significant to maintain normal traffic order.The occurance of traffic accident decides by many factors,including mental status of drivers,speed and running route of vehicles,weather,weight of vehicles,and traffic condition et al.For running vehicles in a road section,an appropriate speed limit and driving route trestrict due to the weather,traffic condition,and road design parameters（slop and curvature,type of pavement meaterial） will decrease the traffic accident.Financial supported by Hi-teeh Research and Development Program of China （2006AA11Z117）,based on the traffic accident control,a multi-function intelligent vehicle detection sensor,which can monitor the speed,running route,structure parameters,and weight of vehicles,was designed in this paper.Sensitive materials, package materials,and protection materials were researched and developed.Two type of senosrs,based on PZT ceramics and PLMN ceramics,were preapred and output behavior was measured.The main work and compliments are listed as follow.1.A Cr³⁺ doping sensitive material for intelligent vehicle detection sensor with decade aging rate of 1.18%was prepared,which sintered at 960℃by adding KCl.（1） Pinning effect of Cr³⁺ on domain wall hamper the polarization of sensitive material.Due to the acceleartion of Cr³⁺ on sintering of sensitive material,the piezoelectric constant of sensitive material increase with the increasement of content of Cr₂O₃ when weight content of Cr₂O₃ is lower than or equer to 0.3%.In sensitive material with a Cr₂O₃ wight content more than 0.3%,Cr³⁺ hamper the growing of sensitive material grain.That lead to a large area of crystal boundary and spontaneous polarization in sensitive material grain was restrained.A Higher content of Cr₂O₃ will reduce the piezoelectric constat of sensitive material.The optimum weight content of Cr₂O₃ is 0.3% （2） KCL melt at 770℃and accelerat the sintering of senstive material.Sintering temperature of sensitive material decrease a lot.Simultaneously,replacing of cation by K⁺ decrease the stability of part of electric domain,which promote the stability of piezoelectric constant of sensitive material after thermal processing.（3） Thermal processing promote the stability of piezoelectric constant of sensitive material a lot.An appropriate heat treatment will reduce the decad aging rate to 1.8%.2.An Al₂O₃ package table,which sintered at 1550℃by using cation doping and lower temperature liquid sintering together,was prepared with a bulk resistivity more than 9×10¹²Ω·m,and a water absorption close to zero.（1） An Al₂O₃ package table sintering by using cation doping and lower temperature liquid sintering together have a low sintering temperature.The water absorption of it is near zero.Weight loss under chemical attack is low,and bulk resistivity is high.（2） A TiO₂ doping sintering Al₂O₃ package table has a higher water absorption and lower bulk resistivity than which sintered by using cation doping and lower temperature liquid sintering together.Moreover,mechanical properties of package table sintered at higher temperature drop sharply due to abnormal growth of grains. Properties of lower temperature liquid sintering package table affected greatly by mix propertion,and water absorption of it is high,and bulk resistivity is low.（3） Microstructure,density,water absorption,flexural strength of package table change little with the increasement of sintering time.Weight loss under acid attack and water attack essentially constant and weight loss under alkali attack decreases sharply and then changes slightly with the increasement of sintering time.Bulk resistivity increases rapidly and then changes slightly with the increasement of sintering time.3.Research on mechanical properties,freezing-thawing resistance,chloride corrosion resistance,acid attack resistance of protection material were conducted.A novel method for flexural toughness assement of protection material was putforwad.（1） Coarse polymer fiber could promote the mechanical properties of concrete which equivalent with steel fiber.As the modulus of coarse polymer fiber is 1/7-1/9 of that of steel,it works after the failure of concrete. （2） Because of the "deflection spring-back" in coarse polymer fiber reinforced concrete,present methods for flexural toughness assessment for fiber reinforced concrete do not fit it.In this paper mean square of stress ratio of "deflection spring-back" to peak point and deflection ratio of "deflection spring-back" to peak point is suggested as the evaluation index.（3） Coarse polymer fiber could promote the freezing-thawing resistance of concrete.However,the reinforce effect of coarse polymer fiber is lower than steel fiber.Otherwise,the resistance of coarse polymer fiber reinforced concrete to cholirde and acik attack is higher than the concrete reinforced by steel fiber.4.Intelligent vehicle detection sensors base PZT and PLMN ceramics were prepared.Output behavior of the sensors were investigated under various pressure, load time,temperature.Output behavior before and after fatigure load were investigated also.（1） Output-pressure curve of intelligent vehicle detection sensor based PZT ceramic has good linearity within pressure limits from 0.1MPa to 2MPa,whereas Output-pressure curve of intelligent vehicle detection sensor based PLMN ceramic was linear only within pressure limits from 0.1MPa to 1.5MPa.（2） Output to pressuer ration of intelligent vehicle detection sensor based PZT ceramic change little when load time is shorter than 0.1 s and it will decreae with the increasement of load time.Output to pressuer ration reduce with the reducing of pressure in the same load time.Output to pressuer ration of intelligent vehicle detection sensor based PZT ceramic decreaes with the increasement of load time.（3） Output of intelligent vehicle detection sensors based PZT and PLMN ceramics increase at first and then decrease and linearity of output-pressure curve deteriorate with the rise of temperature in the temperature range from-20℃to 60℃.（4） Fatigure load have little impact on output of intelligent vehicle detection sensors based PZT and PLMN ceramics.更多还原