電子連接器金屬彈片磨耗分析與驗證

Abstract

輸出/輸入型態電子連接器經過數萬次插入/拔出後，插拔力量通常因插拔次數增加而顯著下降，其主因之一係電子連接器內之金屬彈片磨耗所致。本研究以音頻母座(audio-jack)電子連接器為檢視對象，當其插拔力量不符產品規範時，定義為疲勞失效。執行有限元素分析進行此類電子連接器內鎳銅/磷青銅合金彈片之耐久性評估，彈片材料假設為均向性，具備彈/塑性行為，與遵循均向性硬化法則。採用Archard磨耗法則計算金屬彈片之磨耗量，其值多寡係由金屬彈片與匹配公端子間之接觸壓力，滑移距離，與材料硬度等決定。撰寫使用者副程式UMESHMOTION搭配有限元素分析商用軟體ABAQUS，計算金屬彈片接觸面相關節點位移量，獲致插拔力量與循環週期次數之關係。藉由倍數因子模擬金屬彈片經歷20000次插入/拔出循環週期之插拔力量變化，大幅提升數值運算效率。分析結果並與相對應實驗量測進行驗證。本研究流程可應用於其他設計/型態電子連接器金屬彈片之疲勞壽命評估。

Insertion/withdrawal forces of metallic terminals of audio-jack electronic connectors usually decrease significantly with increasing mating/unmating cycles. A major mechanism causing such a phenomenon could be due to wear performed on the metallic terminal. In this study, fatigue failure of the terminals is defined as either the insertion force or the withdrawal force going beyond the range of the corresponding specification requirements, and a finite element analysis is carried out to assess the durability of the terminals. Copper alloys with an assumption of isotropy are adopted for the terminal material. Elastic-plastic copper alloys with assumptions of isotropy and isotropic hardening for the terminal materials are adopted in the analysis. The Archard model is used to account for abrasions as a function of contact pressure, sliding distance, and hardness. A user subroutine UMESHMOTION integrated in the commercial package ABAQUS is coded to control the movement of the contact surfaces. Variations of the insertion/withdrawal force over 20000 mating/unmating cycles are efficiently calculated by introducing multiplication factors into the simulations. Calculated results are further validated by the associated experimental measurements. The current analysis procedure is then expected to be applied to the fatigue life assessment of other electronic connector terminals.