基于ABAQUS的振动筛大梁裂纹有限元分析

    ABAQUS-based finite element analysis of cracking failure of the girder of vibrating screen

    • 摘要: 为研究振动筛大梁正常工况与产生裂纹后的振动状态的差别,以AHS3661型振动筛大梁为研究对象,对其进行了有限元的模态分析和受迫振动分析。结果表明:在无裂纹情况下大梁受迫振动的模拟最大应力为89 MPa,最大位移接近10 mm,与现场实测情况相符,验证了有限元分析的有效性;大梁近激振器处存在5 mm未贯穿钢板裂纹时,大梁受迫振动最大位移达到19.5 mm,最大应力位于裂纹处,数值为201 MPa;大梁近激振器处存在10 mm贯穿钢板裂纹时,大梁受迫振动最大位移达到93.4 mm,最大应力升高至577 MPa;大梁中部存在5 mm未贯穿钢板裂纹时,大梁最大振幅为18.3 mm,最大应力位于裂纹处且数值达到291 MPa;大梁中部存在10 mm贯穿钢板裂纹时,大梁最大振幅为27.8 mm,最大应力位于裂纹处,数值为482 MPa;总体而言,大梁产生裂纹后,大梁的模态振型发生改变,固有频率上升,大梁的振动幅值出现增大,裂纹附近产生显著高于其他区域的应力。研究结果可作为现场实际故障诊断的理论参考,为振动筛预防维修提供一定依据。

       

      Abstract: In order to investigate the change of vibrating state of vibrating screen’s girder before and after appearance of cracks on the girder, ABAQUS-based finite element analysis on modality and forced vibration state is made with the girder of the AHS3661 vibrating screen as the object study. Analysis shows that in the absence of cracks, the simulated maximum stress of forced vibration of the girder is 89 MPa with a maximum displacement approaching 10 mm, which are consistent with the actually measured values and testify the validity of the F-E analysis in this regard; with the appearance on the girder near the exciter of a 5 mm-deep crack without penetrating through the steel plate, the displacement of the girder under forced vibration reaches 19.5 mm with the maximum stress appearing at the cracking point with a magnitude of 201 MPa; in the presence of a 10 mm crack near the exciter, which extents through the steel plate, the maximum displacement of the girder under forced vibration reaches 93.4 mm with the maximum stress going up to 577 MPa; in the case that a 5 mm crack appears in the middle section of the girder, the girder tends to vibrate with a maximum amplitude of 18.3 mm and a maximum stress of 291 MPa at the cracking point; and at the time when there appears in the middle section of the girder a 10 mm crack which extends through the steel, the girder is seen to vibrate with a maximum amplitude of 27.8 mm, and a maximum stress of 482 MPa at the cracking point. Viewed as a whole, cracking of the girder would cause the girder to undergo changes in vibration mode and to vibrate with increased natural frequency and amplitude, causing as a result the stress near the cracking point to be noticeably higher than those in other areas. The work in the paper may serve as a theoretical basis for making fault diagnosis on site and adoption of preventive maintenance measures.

       

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