CFRP加固X型圆钢管相贯节点焊缝极限承载力研究

阳勇; 何响

doi:10.12299/jsues.23-0109

CFRP加固X型圆钢管相贯节点焊缝极限承载力研究

doi: 10.12299/jsues.23-0109

阳勇,
何响

贵州大学土木工程学院, 贵阳 550025

详细信息

作者简介:
阳勇：阳　勇（1998−），男，在读硕士，研究方向为空间钢管结构加固. Email：1208083351@qq.com

中图分类号: TU392.3
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出版历程
- 收稿日期: 2023-04-25
- 刊出日期: 2023-09-30

Study on ultimate bearing capacity of CHS X-joints strengthened with CFRP

YANG Yong,
HE Xiang

School of Civil Engineering, Guizhou University, Guiyang 550025, China

摘要

摘要: 为研究碳纤维增强塑料（CFRP）对X型圆钢管相贯节点的影响，对ABAQUS有限元软件进行二次开发，运用Fortran语言将VGM模型编译成VUSDFLD子程序对90个节点模型进行有限元分析，并研究支主管外径比β、主管径厚比γ、CFRP黏贴长度与主管直径之比L、CFRP黏贴层数n对节点承载力的影响. 结果表明：CFRP可以减小节点的应力集中，提高节点的承载力，节点开裂会发生在相贯线鞍点焊缝内侧与支管相交的焊根处，随着荷载增加，裂纹会从焊缝鞍点沿着相贯线向冠点发展. 对节点进行参数分析可以发现：随着γ的增加，节点极限承载力逐渐减小；随着β的增大，节点极限承载力逐渐增加；随着n和L的增加，节点极限承载力会有所提高. 本文节点的破坏发生在焊缝，提出CFRP加固X型圆钢管相贯节点焊缝承载力建议公式，对比有限元结果可以发现，节点主管壁厚较小，支管外径较大时，拟合公式的结果存在不安全.
- 加固 /
- 相贯节点 /
- 碳纤维增强塑料 /
- 子程序 /
- 焊缝
Abstract: In order to study the influence of carbon fiber reinforced plastic (CFRP) on the X-shaped circular steel tubular joints, the ABAQUS finite element software was redeveloped. The VGM model was compiled into the VUSDFLD subroutine by Fortran language. The finite element analysis of 90 joint models was carried out, and the effects of the ratio of the outer diameter of the branch to the main pipe β, the ratio of the diameter to the thickness of the main pipe γ, the ratio of the length of CFRP to the diameter of the main pipe L, and the number of CFRP layers n on the bearing capacity of the joints were studied. The results show that CFRP can reduce the stress concentration of the joint and improve the bearing capacity of the joint. The cracking of the joint will occur at the weld root where the inner side of the saddle point weld of the intersecting line intersects with the branch pipe. With increasing of the load, the crack develops from the weld saddle point along the intersecting line to the crown point. Parameters analysis of the joint show that with the increasing of γ, the ultimate bearing capacity of the joint decreases gradually, with the increasing of β, the ultimate bearing capacity of the joint increases gradually, with the increasing of n and L, the ultimate bearing capacity of the joint will increase. For the failure of the joint occured in the weld, the formula for the weld bearing capacity of the CFRP strengthened X-shaped circular steel tube intersecting joint was proposed. Compared with the finite element results, it can be found that the results of the formula fitted are unsafe when the wall thickness of the main pipe of the joint is small and the outer diameter of the branch pipe is large.
- strengthening /
- intersecting connection /
- carbon fiber reinforced plastic (CFRP) /
- subroutine /
- weld bead

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图 1 试验与有限元模拟节点的破坏模式

Figure 1. Failure modes of test and finite element simulation joints

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图 2 试验与有限元模拟节点的荷载-位移曲线

Figure 2. Load-displacement curves of test and finite element simulation joints

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图 3 节点有限元模型

Figure 3. Node finite element model

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图 4 CFRP加强X型圆钢管相贯节点裂纹扩展示意图

Figure 4. Crack propagation diagram of CFRP reinforced X-shaped circular steel tubular joints

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图 5 γ对CFRP加强X型节点受拉极限承载力的影响

Figure 5. Effect of γ on ultimate tensile capacity of CFRP-strengthened X-joints

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图 6 β对CFRP加强X型节点受拉极限承载力的影响

Figure 6. Effect of β on ultimate tensile capacity of CFRP-strengthened X-joints

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图 7 n对CFRP加强X型节点受拉极限承载力的影响

Figure 7. Effect of n on ultimate tensile capacity of CFRP-strengthened X-joints

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图 8 L对CFRP加强X型节点受拉极限承载力的影响

Figure 8. Effect of L CFRP on ultimate tensile capacity of CFRP-strengthened X-joints

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图 9 有限元模拟与公式计算对比图

Figure 9. Comparison diagram between finite element simulation and formula calculation

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表 1 节点试件几何尺寸

Table 1. Geometric dimensions of joint specimens

节点类型	主管尺寸/ mm	支管尺寸/ mm	CFRP 层数	CFRP长度/ mm	CFRP铺设方向
T0	Φ194 × 6	Φ127 × 6	—	—	—
T1	Φ194 × 6	Φ127 × 6	2	682	[0°/90°]
T2	Φ194 × 6	Φ127 × 6	2	682	[45°/135°]

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表 2 断裂参数

Table 2. Fracture parameters

材料	η	特征长度L*
材料	η	下限	平均值	上限
母材	2.55	0.087	0.201	0.473
熔敷金属	2.63	0.062	0.202	0.311
热影响区	2.53	0.072	0.329	0.671

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表 3 CFRP材料参数

Table 3. CFRP material parameters MPa

纵向弹性模量	横向弹性模量	泊松比	纵向剪切模量	横向剪切模量
230000	40000	0.27	24000	14300

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表 4 Hashin失效准则参数

Table 4. Hashin failure criterion parameters MPa

纵向拉伸强度	纵向压缩强度	横向拉伸强度	横向压缩强度	纵向剪切强度	横向剪切强度
1830	895	31.3	124.5	72.0	62.3

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表 5 管节点几何尺寸

Table 5. Geometric dimensions of tubular joints mm

主管尺寸	支管尺寸	焊脚尺寸h_f	焊缝计算长度l_w	θ/(°)
Φ150 × 6	Φ60 × 6	7.2	187.43	90
Φ150 × 6	Φ90 × 6	7.2	282.98	90
Φ150 × 6	Φ120 × 6	7.2	390.87	90
Φ150 × 8	Φ60 × 6	7.2	187.43	90
Φ150 × 8	Φ90 × 6	7.2	282.98	90
Φ150 × 8	Φ120 × 6	7.2	390.87	90
Φ150 × 10	Φ60 × 6	7.2	187.43	90
Φ150 × 10	Φ90 × 6	7.2	282.98	90
Φ150 × 10	Φ120 × 6	7.2	390.87	90

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表 6 参数取值

Table 6. Parameter values

参数	取值
β	0.4、0.6、0.8
γ	7.50、9.38、12.50
L	1.2、1.6、2.0
n	3、6、9
CFRP厚度/mm	0.167
CFRP黏贴方式	CFRP碳纤维束与主管轴线平行成0°方向

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表 7 X型圆钢管节点承载力结果

Table 7. Bearing capacity results of X-type circular steel tubular joints

编号	γ	β	n	L	N_K/kN	N_max/kN	ψ
X1	7.5	0.4	0	0	370.11	399.74	0
X2	7.5	0.4	3	1.2	380.56	412.34	1.032
X3	7.5	0.4	3	1.6	380.72	413.98	1.036
X4	7.5	0.4	3	2.0	386.35	417.60	1.045
X31	9.38	0.4	0	0	344.70	362.22	0
X32	9.38	0.4	3	1.2	359.63	378.43	1.045
X33	9.38	0.4	3	1.6	361.61	380.47	1.050
X34	9.38	0.4	3	2.0	363.13	381.98	1.055
X61	12.5	0.4	0	0	287.86	311.51	0
X62	12.5	0.4	3	1.2	308.15	326.04	1.047
X63	12.5	0.4	3	1.6	311.66	332.28	1.067
X64	12.5	0.4	3	2.0	314.40	335.38	1.077
X65	12.5	0.4	6	1.2	314.99	335.68	1.078
X66	12.5	0.4	6	1.6	322.13	344.05	1.104
X67	12.5	0.4	6	2.0	325.94	348.45	1.119
X68	12.5	0.4	9	1.2	321.32	342.96	1.101
X69	12.5	0.4	9	1.6	327.72	350.48	1.125
X70	12.5	0.4	9	2.0	337.45	351.36	1.128
X71	12.5	0.6	0	0	357.14	367.14	0
X72	12.5	0.6	3	1.2	374.61	382.92	1.043
X73	12.5	0.6	3	1.6	381.75	390.81	1.064
X74	12.5	0.6	3	2.0	387.93	397.17	1.082
X75	12.5	0.6	6	1.2	383.71	393.61	1.072
X76	12.5	0.6	6	1.6	388.80	404.93	1.103
X77	12.5	0.6	6	2.0	397.22	409.40	1.115
X78	12.5	0.6	9	1.2	390.35	398.75	1.086
X79	12.5	0.6	9	1.6	397.97	409.09	1.114
X80	12.5	0.6	9	2.0	408.27	418.64	1.140
X81	12.5	0.8	0	0	374.03	385.16	0
X82	12.5	0.8	3	1.2	395.20	404.31	1.050
X83	12.5	0.8	3	1.6	399.78	404.52	1.050
X84	12.5	0.8	3	2.0	404.11	409.09	1.062
X85	12.5	0.8	6	1.2	398.74	409.46	1.063
X86	12.5	0.8	6	1.6	406.93	410.32	1.065
X87	12.5	0.8	6	2.0	415.39	423.74	1.100
X88	12.5	0.8	9	1.2	408.64	417.28	1.083
X89	12.5	0.8	9	1.6	417.73	423.66	1.100
X90	12.5	0.8	9	2.0	425.57	430.92	1.119
注：N_k为节点开裂时的荷载值；N_max为节点极限荷载值；ψ为极限承载力提高系数.

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表 8 有限元模拟与公式计算结果对比表

Table 8. Comparison between finite element simulation and formula calculation results

节点编号	有限元模拟ψ	公式计算ψ_p	有限元模拟节点极限承载力N_max/kN	公式计算焊缝承载力设计值N/kN
X82	1.050	1.046	404.31	414.99
X83	1.050	1.056	404.52	418.97
X84	1.062	1.065	409.09	422.58
X85	1.063	1.069	409.46	424.30
X86	1.065	1.084	410.32	430.08
X87	1.100	1.097	423.74	435.32
X88	1.083	1.088	417.28	431.59
X89	1.100	1.106	423.66	438.79
X90	1.119	1.122	430.92	445.31

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