組合板內聚強度測試時的音射現象

Acoustic Emission during Internal Bond Testing of PB and MDF

黃國雄(Gwo-Shyon Hwang) ； 黃彥三(Van-San Huang)

《林產工業》 8卷2期 (1989/06) Pp. 29-37

摘要

音射（簡稱AE）係固體在發生塑性變形或破壞時，將內部所儲蓄之應變能釋放出來而產生彈性波（超音波）之現象。物體受力在破壞之前，便能發生頻度與強度不同之AE，將AE以敏感計測裝置測定，可檢測物體龜裂之發生，進而可預測破壞之時間與位置。本研究之目的在探討粒片板（PB）與中密度纖維板（MDF）內聚強度測試時之AE現象，以了解AE之發生與應力、應變之關係。試驗結果歸結如下：1.MDF之破壞應變、內聚強度與AE次數均較PB小。2.AE主要發生在荷重末期之後半，然在接近破壞荷重時，MDF之AE增加率較PB快。3.PB與MDF兩者之破壞應變及內聚強度，均與AE次數無明顯之關係存在。

關鍵字

音射 ； 粒片板 ； 纖維板 ； 內聚強度 ； 應變 ； 應力

並列摘要

Acoustic emission (AE) monitoring is a non-destructive testing technique, recently used to predict the failure of finger joints and control drying rate of lumber in wood research. In this paper, particleboard(PB) and medium density fiberboard (MDF) were monitored for AE during internal bond (IB) testing. The purpose of this experiment is to know the AE generation in the process of IB testing. Results obtained are as follows: 1. The strain at failure, IB strength and AE counts of MDF are less than PB. 2. The most of AE counts generate at the latter half of last loading, and the AE increase rate of MDF is faster than PB when the specimens are about the failure in IB testing. 3. There is no evident correlation between accumulated AE counts to strain at failure and IB strength for both PB and MDF.

並列關鍵字

Acoustic emission ； Particleboard ； Fiberboard ； Internal bond ； Strain ； Stress.