CAJ | 학술논문

探索苜蓿在压捆过程中，由松散状态压缩成草片时在压捆室不同位置的轴向应力变化规律及传递模型。以草片为研究对象，选喂入量为4 kg/次，在草物料压捆试验台上进行了5种截面的压捆试验。每种截面布设2套压力传感装置和3个位移传感器，由基于虚拟仪器的草物料压缩测试系统采集各传感器的信号，记录了每次压缩时草片的压缩与恢复应力和位置、草片的压缩量及回弹量等数据。结果表明苜蓿在不同截面下压缩与恢复应力具有相同的传递规律，但截面尺寸影响草片的最大压缩应力和最小恢复应力的数值且为非线性关系。指出了由松散苜蓿压缩成草片所需要的压缩应力最大，是压捆机设计中的基本参数。揭示了草片最大压缩应力随位移的变化呈指数下降，在压缩室内草片（4～5个草片）的压缩应力较高，在捆草室内草片的压缩应力较低，建议压缩室长度为900～1000 mm。草片最小恢复应力表现为随位移增加而增加，达到一定位置时随位移的增加而下降。通过回归分析，获得了苜蓿在压捆过程中压缩与恢复应力传递规律和相应的数学模型，其复相关系数均大于0.9091，说明压缩与恢复应力和草片的位置密切相关，模型回归效果较好。试验结果可为草物料压捆机的动力选择和优化设计提供基础数据和理论依据。
탐색목숙재압곤과정중，유송산상태압축성초편시재압곤실불동위치적축향응력변화규률급전체모형。이초편위연구대상，선위입량위4 kg/차，재초물료압곤시험태상진행료5충절면적압곤시험。매충절면포설2투압력전감장치화3개위이전감기，유기우허의의기적초물료압축측시계통채집각전감기적신호，기록료매차압축시초편적압축여회복응력화위치、초편적압축량급회탄량등수거。결과표명목숙재불동절면하압축여회복응력구유상동적전체규률，단절면척촌영향초편적최대압축응력화최소회복응력적수치차위비선성관계。지출료유송산목숙압축성초편소수요적압축응력최대，시압곤궤설계중적기본삼수。게시료초편최대압축응력수위이적변화정지수하강，재압축실내초편（4～5개초편）적압축응력교고，재곤초실내초편적압축응력교저，건의압축실장도위900～1000 mm。초편최소회복응력표현위수위이증가이증가，체도일정위치시수위이적증가이하강。통과회귀분석，획득료목숙재압곤과정중압축여회복응력전체규률화상응적수학모형，기복상관계수균대우0.9091，설명압축여회복응력화초편적위치밀절상관，모형회귀효과교호。시험결과가위초물료압곤궤적동력선택화우화설계제공기출수거화이론의거。
This study attempted to investigate the transfer rule of the axial stress and springback models at the different locations of the compression chamber in the compression process of alfalfas, in which the alfalfa was compressed from the loose state into a grass piece. By taking dried high-quality alfalfa as the experimental material and 4 kg as the feeding capacity, with 5 different cross-section sizes (namely 360 mm×460 mm, 385 mm×460 mm, 410 mm×460 mm, 460 mm×460 mm and 510 mm×460 mm) of the compression chamber, the compression experiments were conducted under the conditions of a given compression chamber length, and initial density and moisture content of alfalfa. In order to measure the axial stress, including the compression and springback stress, the 10 moveable pressure sensors were used for the cross-section size of the compression chamber, and 2 pressure sensors and 3 displacement sensors were installed in each section. The compression and springback stress, the location of the grass piece in the compression chamber, the amount of compression, and springback value were obtained and stored in an Excellspreadsheet table by the data acquisition system based on virtual instrument technology, and the online curves of the axial force, the compression displacement, and the thickness of the grass pieces were displayed. All data was imported into the software Matlab and the axial stress curves versus the location of the grass piece in the compression of alfalfa were given. Then curve fitting of the maximum stress and the minimum springback stress were done respectively, the transfer rule of the compression and springback stress and the corresponding mathematic model were obtained. The results showed that the squared multiple correlation coefficient was greater than 0.9091, indicating that the compression and springback stress were closely related to the location of the grass piece and that the model regression effect was better. The compression and springback stresses had the similar transfer rules for different cross-section sizes of the compression chamber, and the cross-section size of the compression chamber had effects on the maximum compression stress and maximum springback stress of alfalfa. The compression stress required from loose alfalfa into the grass piece was highest, which was a fundamental parameter in designing the baler. The compression stress of 4-5 the grass piece was higher in the front of the compression chamber but lower in the rear parts of the compression chamber. It suggested that:1) the suitable length for the compression chamber was 900-1 000 mm;and 2) the reinforcement structures should be added in the front part of the compression chamber to satisfy the strength and stiffness and to decrease baler weight. The study revealed that the envelop line of minimum spingback stress increased with increasing compression displacement, and the trend was opposite when it reached a certain location. Eventually, the difference between the axial compression and springback force of the grass piece was decreased and then became stable. It indicated that the damping plate should be set at the front part and the rear of the compression chamber, which would lead to the maximum springback force occurring in the compression process. As such, the baling efficiency and qualified products were improved. The results here provide valuable information for parameters optimization in the compression process and power choice.