基于误差传递原理的水尺计重误差分析

Error Analysis of Draft Survey Based on Error Transfer Principle

在误差相关理论和水尺计重方法的基础上,分析了水尺计重过程中误差的传递规律。通过梳理水尺计重过程存在的系统误差,甄别出了锚链和缆绳的垂直分力造成的系统误差尚未被有效修正。在JTS 144-1-2010《港口工程荷载规范》和现有研究成果的基础上,对船舶风压力和水流力的横向和纵向分力进行了分析,得出了船体所受的水平外力(即锚链张力水平分力的反作用力),并结合力学原理以及船舶锚泊状态建立了锚链张力垂直分力的计算模型,其可用于求解由锚链垂直分力造成系统误差的修正量。算例表明:在风速为13 m/s,流速达到4 kn(1 kn=1.852 km/h)时,仅这一项误差就已达到了水尺计重允许误差的28%。

Based on the overview of the error correlation theory and the draft survey method,the error propagation law of the draft survey were analyzed.By reading a large number of documents to sort out the systematic errors in the weight measurement process,in many errors,the systematic error caused by the vertical component of the anchor chain and the cable has not been effectively corrected.Based on the JTS144-1-2010"Port Engineering Load Specification"(hereinafter referred to as specifications)and the existing research results,the lateral and longitudinal component forces of ship wind pressure and water flow force are analyzed and obtained.The horizontal external force of the hull(i.e.,the reaction force of the horizontal tension component of the anchor chain)were combined with the mechanical principle and the anchoring state of the ship to establish a calculation model of the vertical component of the anchor tension,which can be used to solve the correction of systematic error caused by the vertical component of anchor chain.The example showed that when the wind speed is 13 m/s and the flow rate reaches 4 kn(1 kn=1.852 km/h),only this error has reached 28% of the allowable error of the water gauge.