The impact of skidding operations on forest soils can be divided into three major categories： soil profile disturbance, soil compaction, and soil puddling and rutting. The present study was designed as a factorial ex...The impact of skidding operations on forest soils can be divided into three major categories： soil profile disturbance, soil compaction, and soil puddling and rutting. The present study was designed as a factorial experiment in the Kheyrud Forest with a Timberjack cable skidder to evaluate the influences of number of machine passes and soil moisture of skid trails on rutting over a fine-grained soil, and to quantify these effects. The effects of soil moisture of 20% 30%, 30% 40% and 40% 50% and different levels of compaction were studied. Compaction treatments were applied using different numbers of skidding passes （1, 5, 10, 15, 20, 25, 30 times）. Result shows that an increase in the number of machine passes could increase rut depth, but the majority of rutting was occurred after the initial few machine passes. Also rut depth at soil moisture of 40% 50% was higher than rut depths at soil moisture of 30% 40% and 20% 30%. The average rut depth in soil with 20% 30%, 30% 40% and 40% 50% moisture was 17, 22 and 35 cm, respectively. Rut depths were increased significantly with soil moisture and number of machine passes. It is suggested that skidding operations should be planned when soil conditions are dry in order to minimize rutting., but if skidding must be done under wet conditions, the operations should be stopped when machine traffic could create deep ruts.展开更多
The test and analysis on the chair system of homemade J80 skidder was carried out. on the basis of the study result, the important parameters, the spring rigidity and the damping coefficient of J80 skidder chair, were...The test and analysis on the chair system of homemade J80 skidder was carried out. on the basis of the study result, the important parameters, the spring rigidity and the damping coefficient of J80 skidder chair, were optimized and some suggestions were put forward for improving the riding comfort of the skidder seat.展开更多
林区道路崎岖,沟壑极多,壕沟是其中一种极限工况,跨越壕沟能力的高低反映了集材机通过性能的强弱。利用Solidworks和Recur Dyn软件对集材机虚拟样机及其可更换三角形履带行动装置进行建模,用Recur Dyn软件对集材机在不同预张紧力、速度...林区道路崎岖,沟壑极多,壕沟是其中一种极限工况,跨越壕沟能力的高低反映了集材机通过性能的强弱。利用Solidworks和Recur Dyn软件对集材机虚拟样机及其可更换三角形履带行动装置进行建模,用Recur Dyn软件对集材机在不同预张紧力、速度及工作状态(空载、装车和集材)下的跨越壕沟能力进行动力学仿真分析。研究结果表明:以预张紧力为24 k N(车重50%)跨越壕沟时,集材机运行更为稳定;预张紧力过大(38.4 k N)或过小(14.4 k N)均会导致履带断链。集材机在跨越壕沟时,速度不应低于14 rad/s,适当地提高速度有助于集材机跨越更宽的壕沟,但速度越大对履带性能要求也越高。多功能集材机空载时跨越的壕沟宽度不应超过900mm,装车时不应超过800 mm,集材时不应超过1 100 mm。展开更多
为设计一种适于我国林区作业条件的高效低耗的多功能集材机械,将可更换三角形履带装置应用于集材机上,在理论分析的基础上,利用Solidworks和Recur Dyn软件建立三角形履带集材机虚拟样机和路面模型,对预张紧力、转向角度、路面条件、装...为设计一种适于我国林区作业条件的高效低耗的多功能集材机械,将可更换三角形履带装置应用于集材机上,在理论分析的基础上,利用Solidworks和Recur Dyn软件建立三角形履带集材机虚拟样机和路面模型,对预张紧力、转向角度、路面条件、装车工况和集材工况等影响集材机转向动力学性能的因素进行仿真分析。结果表明:履带预张紧力为19.2 k N(车重40%)时更适于转向;转向角度越大车辆转向越容易但同时车辆振动越大;软地面转向时较硬地面稳定性差,更易发生脱轮或断链;装车或集材转向时各项动力学指标均满足要求,集材机在作业条件下转向平稳。展开更多
The performance of the skidder Timber jack 450 C was presented in timber skidding of non-coniferous trees in hilly and mountainous conditions. An empirical time study was conducted to evaluate the current skidding sys...The performance of the skidder Timber jack 450 C was presented in timber skidding of non-coniferous trees in hilly and mountainous conditions. An empirical time study was conducted to evaluate the current skidding system in Hyrcanian forest in northern Irma for improving production rate of skidding and finding out the production cost for planning. Based on the identified elements of skidding work phase and 130 recorded cycles, we calculated the models for effective time consumption, total productivity, and unit cost. The validity of the model was tested at 95% confidence interval. The average load volume per cycle was 2.82 m3, average one way skidding distance was 450 m, and the average slope was 18%. The average travel speed of unloaded skidder was 5.8 km.h-1, and the average speed of loaded skidder was 0.1 km.h＂~ higher than the speed of the unloaded ones. The travel speed was pre- dominantly affected by longitudinal slopes and types of strip roads. The average speed of pulling the cable was 1.16 km.h-1, and that of load winching was 0.74 km.hl. The average outputs in skidding was 10.6 m^-3.h^-1 and the unit cost was 12.1 USS per hour. The time consumption and productivity of skidding depends on distances and slope, number of logs per cycle, volume, log length, etc. However, the influence of variables is not the same.展开更多
文摘The impact of skidding operations on forest soils can be divided into three major categories： soil profile disturbance, soil compaction, and soil puddling and rutting. The present study was designed as a factorial experiment in the Kheyrud Forest with a Timberjack cable skidder to evaluate the influences of number of machine passes and soil moisture of skid trails on rutting over a fine-grained soil, and to quantify these effects. The effects of soil moisture of 20% 30%, 30% 40% and 40% 50% and different levels of compaction were studied. Compaction treatments were applied using different numbers of skidding passes （1, 5, 10, 15, 20, 25, 30 times）. Result shows that an increase in the number of machine passes could increase rut depth, but the majority of rutting was occurred after the initial few machine passes. Also rut depth at soil moisture of 40% 50% was higher than rut depths at soil moisture of 30% 40% and 20% 30%. The average rut depth in soil with 20% 30%, 30% 40% and 40% 50% moisture was 17, 22 and 35 cm, respectively. Rut depths were increased significantly with soil moisture and number of machine passes. It is suggested that skidding operations should be planned when soil conditions are dry in order to minimize rutting., but if skidding must be done under wet conditions, the operations should be stopped when machine traffic could create deep ruts.
文摘The test and analysis on the chair system of homemade J80 skidder was carried out. on the basis of the study result, the important parameters, the spring rigidity and the damping coefficient of J80 skidder chair, were optimized and some suggestions were put forward for improving the riding comfort of the skidder seat.
文摘林区道路崎岖,沟壑极多,壕沟是其中一种极限工况,跨越壕沟能力的高低反映了集材机通过性能的强弱。利用Solidworks和Recur Dyn软件对集材机虚拟样机及其可更换三角形履带行动装置进行建模,用Recur Dyn软件对集材机在不同预张紧力、速度及工作状态(空载、装车和集材)下的跨越壕沟能力进行动力学仿真分析。研究结果表明:以预张紧力为24 k N(车重50%)跨越壕沟时,集材机运行更为稳定;预张紧力过大(38.4 k N)或过小(14.4 k N)均会导致履带断链。集材机在跨越壕沟时,速度不应低于14 rad/s,适当地提高速度有助于集材机跨越更宽的壕沟,但速度越大对履带性能要求也越高。多功能集材机空载时跨越的壕沟宽度不应超过900mm,装车时不应超过800 mm,集材时不应超过1 100 mm。
文摘为设计一种适于我国林区作业条件的高效低耗的多功能集材机械,将可更换三角形履带装置应用于集材机上,在理论分析的基础上,利用Solidworks和Recur Dyn软件建立三角形履带集材机虚拟样机和路面模型,对预张紧力、转向角度、路面条件、装车工况和集材工况等影响集材机转向动力学性能的因素进行仿真分析。结果表明:履带预张紧力为19.2 k N(车重40%)时更适于转向;转向角度越大车辆转向越容易但同时车辆振动越大;软地面转向时较硬地面稳定性差,更易发生脱轮或断链;装车或集材转向时各项动力学指标均满足要求,集材机在作业条件下转向平稳。
文摘The performance of the skidder Timber jack 450 C was presented in timber skidding of non-coniferous trees in hilly and mountainous conditions. An empirical time study was conducted to evaluate the current skidding system in Hyrcanian forest in northern Irma for improving production rate of skidding and finding out the production cost for planning. Based on the identified elements of skidding work phase and 130 recorded cycles, we calculated the models for effective time consumption, total productivity, and unit cost. The validity of the model was tested at 95% confidence interval. The average load volume per cycle was 2.82 m3, average one way skidding distance was 450 m, and the average slope was 18%. The average travel speed of unloaded skidder was 5.8 km.h-1, and the average speed of loaded skidder was 0.1 km.h＂~ higher than the speed of the unloaded ones. The travel speed was pre- dominantly affected by longitudinal slopes and types of strip roads. The average speed of pulling the cable was 1.16 km.h-1, and that of load winching was 0.74 km.hl. The average outputs in skidding was 10.6 m^-3.h^-1 and the unit cost was 12.1 USS per hour. The time consumption and productivity of skidding depends on distances and slope, number of logs per cycle, volume, log length, etc. However, the influence of variables is not the same.
基金The Special Scientific Research Funds for Forest Non-profit Industry ( 201104007) The Fundamental Research Funds for The Central Universities( DL09BB26)
