噪声与振动控制
譟聲與振動控製
조성여진동공제
NOISE AND VIBRATION CONTROL
2015年
1期
89-92,109
,共5页
振动与波%桥梁振动%梁-板混合单元%车-线-桥耦合振动
振動與波%橋樑振動%樑-闆混閤單元%車-線-橋耦閤振動
진동여파%교량진동%량-판혼합단원%차-선-교우합진동
vibration and wave%bridge vibration%beam-plate hybrid elements%train-track-bridge coupling vibration
在平截面的假定条件下，通过建立梁—板混合单元有限元模型，采用车—线—桥耦合振动分析得到桥梁高频振动响应，再采用声学边界元法分析桥梁结构噪声。以32 m混凝土简支箱梁为例，讨论了不同的梁—板混合模型对计算精度和效率的影响，并与现场试验结果进行对比。由此验证了：在梁—板混合有限元模型中，跨中板单元区域的长度取5倍以上梁高时，桥梁高频振动和结构噪声仿真值均能取得良好的精度，计算效率可提高70%左右。桥梁振动和结构噪声的峰值频率范围为40 Hz～80 Hz，在梁侧传播时具有一定的指向性。采用梁—板混合单元模型计算得到30 m范围内的结构噪声与全板单元模型计算结果基本一致，但在30 m范围外，前者的计算值要比后者小2 dB(Lin)左右。因而，梁—板混合单元模型可有助于提高桥梁车致振动和噪声分析的效率。
在平截麵的假定條件下，通過建立樑—闆混閤單元有限元模型，採用車—線—橋耦閤振動分析得到橋樑高頻振動響應，再採用聲學邊界元法分析橋樑結構譟聲。以32 m混凝土簡支箱樑為例，討論瞭不同的樑—闆混閤模型對計算精度和效率的影響，併與現場試驗結果進行對比。由此驗證瞭：在樑—闆混閤有限元模型中，跨中闆單元區域的長度取5倍以上樑高時，橋樑高頻振動和結構譟聲倣真值均能取得良好的精度，計算效率可提高70%左右。橋樑振動和結構譟聲的峰值頻率範圍為40 Hz～80 Hz，在樑側傳播時具有一定的指嚮性。採用樑—闆混閤單元模型計算得到30 m範圍內的結構譟聲與全闆單元模型計算結果基本一緻，但在30 m範圍外，前者的計算值要比後者小2 dB(Lin)左右。因而，樑—闆混閤單元模型可有助于提高橋樑車緻振動和譟聲分析的效率。
재평절면적가정조건하，통과건립량—판혼합단원유한원모형，채용차—선—교우합진동분석득도교량고빈진동향응，재채용성학변계원법분석교량결구조성。이32 m혼응토간지상량위례，토론료불동적량—판혼합모형대계산정도화효솔적영향，병여현장시험결과진행대비。유차험증료：재량—판혼합유한원모형중，과중판단원구역적장도취5배이상량고시，교량고빈진동화결구조성방진치균능취득량호적정도，계산효솔가제고70%좌우。교량진동화결구조성적봉치빈솔범위위40 Hz～80 Hz，재량측전파시구유일정적지향성。채용량—판혼합단원모형계산득도30 m범위내적결구조성여전판단원모형계산결과기본일치，단재30 m범위외，전자적계산치요비후자소2 dB(Lin)좌우。인이，량—판혼합단원모형가유조우제고교량차치진동화조성분석적효솔。
Computational efficiency is a bottleneck in calculating train-induced high-frequency bridge vibration and as-sociated structure-borne noise. In this paper, based on the plane cross-section assumption, the beam-plate hybrid elements were introduced and the train-track-bridge coupling finite element model was built for analyzing the high-frequency vibra-tion response of the bridge. Then, the acoustical boundary element method was used to compute the structure-borne noise. Taking a 32 m simply-supported box-girder as an example, the computational efficiency and accuracy were investigated through different beam-plate combination models. A field test was also carried out for verification. Results show that if the length of the plate-element region exceeds five times of the height of the girder, the computational efficiency can be raised by 70%without loss of accuracy in comparison with the conventional finite element analysis with plate elements. The domi-nant frequency of bridge vibration and the associated noise is 40 Hz-80 Hz;the structure-borne noise has some directivity along the side of the bridge;in the range beyond 30 m away from the bridge, the results of structure-borne noise calculated by the beam-plate hybrid elements model agree with the whole plate elements model, and the noise level of the former is ap-proximately 2 dB(Lin) smaller than the latter. Hence, the beam-plate hybrid elements are helpful for raising the computation efficiency of bridge vibration and noise induced by trains.
