利用微型平板試片探討疲勞性質

Abstract

進行疲勞性質試驗，微型平板試片比標準試片節省材料與製作成本，改採取微型疲勞試驗機來取代大型材料試驗機，更能藉著其高拉伸頻率來縮短疲勞試驗的時間，且機台體積小、結構簡單，維護較方便。本篇研究係針對微型疲勞試驗機進行改良設計以利進行微型平板試片疲勞試驗，並進行2014-T651鋁合金、7075-T651鋁合金、304不鏽鋼與4340合金鋼的微型平板試片等振幅負載疲勞拉伸試驗和7075-T651鋁合金的微型平板試片高峰拉伸應力減速現象試驗，將上述二種不同負載控制模式的試驗結果與標準試片的試驗結果進行比較以證明微型平板試片疲勞試驗的可行性。各組試驗結果經比較之下均具有關聯性，能夠證實微型平板試片疲勞試驗結果的可信度。

Using miniature specimens could save material and cost during fatigue testing. Conventional fatigue test was conducted by MTS (material test system) which would be time and cost consuming. The purpose of this study was to propose a miniature fatigue test system for evaluating the fatigue properties using miniature specimens. The advantages of miniature fatigue test system included high working frequency, small volume, simple structure, and easy to repair. Materials of the miniature specimens used in this study were 2014-T651 aluminum alloy, 7075-T651 aluminum alloy, 304 stainless steel, and 4340 steel alloy. Constant amplitude loading with or without overload fatigue testing have been carried out. The fatigue crack growth properties results of the miniature specimens were compared with that of the standard specimens. The experimental results show that miniature fatigue test system was practicable.