農產品運銷用瓦楞紙箱於長時間運輸航程之結構強度與通風表現分析

Investigations of Structure Strength and Ventilation Performance for Agriproduct Corrugated Cartons under Long-term Transportation Trip

王丹夆(Tan-Feng Wang)

指導教授 ： 廖國基

國立臺灣大學/生物資源暨農學院/生物機電工程學系/碩士(2021年)

https://doi.org/10.6342/NTU202102952

摘要

瓦楞紙箱係各式產品運輸包裝使用最廣泛之包裝材料之一，國內常應用於農產品之海運外銷。然紙箱可能於運輸航程中因負載重量、環境溫濕度條件、及運輸時間等因素，導致其產生變形及損壞，結構強度因此為瓦楞紙箱設計重要考量因子。瓦楞紙箱係由瓦楞紙板經裁切製作成型，具備多層紙材組成之相對複雜結構。本研究為此提出一分析程序，採用一自動化之材料參數擬合流程，針對瓦楞結構中之裱紙及芯紙進行環壓試驗獲致之力量-位移資料，藉以擬合其正交各向異性彈性材料參數值。採用兩種瓦楞結構均質化程序開發相對應使用者介面，分別獲得結合等效勁度矩陣及橫向剪切勁度之擴充矩陣，抑或正交各向異性彈性搭配異向性降伏準則之材料參數。參考於室溫及冷藏環境條件下量測所得之瓦楞結構紙材之楊氏模數差異，修正其彈性材料參數，並採用冪次法則模型描述紙箱之潛變反應。前述各項數值模擬針對瓦楞結構紙材、紙板、及紙箱均預先進行特徵值挫屈分析，藉此獲得相對應挫屈模態以導入數值模型作為初始幾何缺陷。同時考量瓦楞紙箱之結構強度及通風效益，針對其通風口構型進行改良。考慮紙箱堆疊於氣調櫃內之負載及環境條件，分別採用兩相異構型紙箱進行長時間承壓模擬，其中原構型紙箱展現與實務觀察相似之挫屈變形，模擬結果同時顯示改良構型可有效減少紙箱於運輸航程之形變。採用兩相異構型紙箱於氣調櫃環境進行氣體流動數值分析，顯示改良構型紙箱亦具備較高之空氣流速及通風均勻性。藉由上述開發之分析程序，可協助相關產業於設計階段快速評估紙箱較佳構型。

關鍵字

瓦楞紙箱 ； 瓦楞結構均質化 ； 潛變效應 ； 特徵值挫屈分析 ； 數值分析

並列摘要

Load-carrying capability of corrugated board cartons packaging fresh agriproducts must be significant enough. Collapse of the carton palletized in a controlled atmosphere container is commonly observed during a relatively long shipping period. A finite element analysis is conducted to investigate the mechanical performance of the carton located at bottom of the stacked pile. In order to dramatically reduce the computational cost, two homogenization approaches of the corrugated structure are adopted in the present study. Effects of both temperature and moisture on the strength of the carton are considered in the simulations. Creep behavior is further implemented into the numerical analysis to describe the stiffness decay of the carton. Simulation results show that the original design of carton performs local buckling deformation similar to the experimental observation, and the modified design can exhibit rather smaller collapse after the transportation trip. Moreover the modified design provides better uniformity of ventilation based on the computational fluid dynamics analysis. Current proposed procedure is considered to be promising for the selection of liner/core paper that compose the corrugated board and the assessment of vented cartons in the early design stage.

並列關鍵字

corrugated board carton ； homogenization ； creep ； buckling analysis ； numerical analysis

參考文獻

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