CFRP加固木柱的轴压损伤性能试验研究

黄俊杰; 佘艳华; 张鹤凡; 何佳明

CFRP加固木柱的轴压损伤性能试验研究

长江大学　城市建设学院, 荆州 434023

基金项目: 国家自然科学基金 (51408057)；住房与城乡建设部科学技术项目 (2021-K-086)；长江大学创新训练项目 (Yz2023008)

详细信息

通讯作者:
佘艳华，博士，副教授，硕士生导师，研究方向为工程材料和结构检测　E-mail: syh916@126.com

中图分类号: TU366
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- 被引次数: 0
出版历程
- 收稿日期: 2024-01-02
- 修回日期: 2024-02-02
- 录用日期: 2024-02-28
- 网络出版日期: 2024-03-30

Experimental study on axial compressive damage performance of CFRP-reinforced wood columns

School of Urban Construction, Yangtze University, Jingzhou 434023, China

Funds: National Natural Science Foundation of China (51408057); Ministry of Housing and Urban Rural Development Science and Technology Project (2021-K-086); Innovation Training Program of Yangtze University (Yz2023008)

摘要

摘要: 为研究碳纤维增强树脂基复合材料(CFRP)加固木柱的轴压损伤性能及破坏机制，对6组不同CFRP缠绕方式的木柱开展了轴向压缩试验并进行了实时声发射(Acoustic emission, AE)监测。分析了不同缠绕层数和不同缠绕角度对CFRP加固木柱破坏形式、力学性能、吸能性能和声发射参数演化规律的影响。结果表明：CFRP的加固能明显改善木材的力学性能，抑制脆性破坏的发生；随着缠绕层数、角度的增大，木柱的极限承载力从112.63 kN提升至161.21 kN，位移延性系数也从1.44提升至1.72；CFRP缠绕层数、角度的增加能够显著提高CFRP加固木柱在轴压损伤过程中的稳定性和吸能能力；根据声发射的振铃计数演化特征可以将CFRP加固木柱的损伤过程分为弹性、压缩屈服和损伤破坏三个阶段；随着缠绕层数、角度的增加，声发射峰值频率逐渐从低频区间(0~80 kHz)向高频区间(160~240 kHz)过渡，损伤形式从大尺度损伤转变为小尺度损伤；不同缠绕方式的木柱声发射能量概率密度均遵循幂律无尺度分布，6种加固方式下，临界指数分别为1.31、1.33、1.36、1.43、1.49、1.57；临界指数随着缠绕层数、角度的增大而增大，CFRP的加固限制了木材内部裂纹的发展，减弱了内部结构的劣化。
- 碳纤维增强树脂基复合材料 /
- 木柱 /
- 损伤性能 /
- 声发射 /
- 临界指数
Abstract: To study the axial compression damage performance and failure mechanism of wood columns strengthened with carbon fiber reinforced polymer (CFRP), axial compression tests and real-time acoustic emission (AE) monitoring were carried out on six groups of wood columns with different CFRP winding methods. The effects of different winding layers and winding angle on the damage forms, mechanical properties, energy absorption properties and acoustic emission parameters of CFRP-reinforced wood columns were analyzed. The results show that: the reinforcement of CFRP can significantly improve the mechanical properties of wood, inhibit the occurrence of brittle damage; with the increase of the winding layers and angle, the ultimate bearing capacity of the wood columns increases from 112.63 kN to 161.21 kN, and the displacement ductility factor also increases from 1.44 to 1.72; the increase of CFRP winding layers and angle can significantly improve the stability and energy absorption capacity of CFRP-reinforced wood columns in the axial compression damage process; according to the evolution characteristics of acoustic emission ringing count, the damage process of CFRP-reinforced wood columns can be divided into three stages: elastic stage, compressive yield stage and damage failure stage; with the increase of the winding layers and angle, the peak frequency of acoustic emission gradually transitions from the low-frequency range (0~80 kHz) to the high-frequency range (160~240 kHz), and the damage form changes from large-scale damage to small-scale damage; the probability density of acoustic emission energy of wood columns with different winding methods follows a power-law scale-free distribution, the critical indices under six reinforcement methods are 1.31, 1.33, 1.36, 1.43, 1.49 and 1.57, respectively; the critical index increases with the increase of winding layers and angles, the reinforcement of CFRP limits the development of internal cracks and weakens the deterioration of the internal structure of the wood.
- carbon fiber reinforced polymer /
- wood columns /
- damage performance /
- acoustic emission /
- critical index

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图 1 木材干燥过程

Figure 1. Wood drying process

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图 2 CFRP加固木柱的制备工艺流程

Figure 2. Preparation process of CFRP-reinforced wood columns

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图 3 缠绕角度示意图

Figure 3. Schematic diagram of winding angle

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图 4 声发射传感器位置

Figure 4. Position of the AE sensors

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图 5 加载装置图

Figure 5. Loading device diagram

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图 6 CFRP加固木柱的破坏形式

Figure 6. Failure forms of CFRP-reinforced wood columns

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图 7 CFRP加固木柱的荷载-位移曲线

Figure 7. Load-displacement curves of CFRP-reinforced wood columns

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图 8 CFRP加固木柱的峰值荷载和平均荷载

Figure 8. Peak force and mean force of CFRP-reinforced wood columns

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图 9 CFRP加固木柱的压溃效率和比吸能

Figure 9. Crush force efficiency and specific energy absorption of CFRP-reinforced wood columns

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图 10 CFRP加固木柱振铃计数、荷载和时间的关系

Figure 10. Relationship between ringing count, load and time of CFRP-reinforced wood columns

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图 11 CFRP加固木柱的峰值频率分布密度图

Figure 11. Peak frequency distribution density plot of CFRP-reinforced wood columns

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图 12 CFRP加固木柱的声发射能量概率密度分布图

Figure 12. Probability density distribution of AE energy of CFRP-reinforced wood columns

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图 13 CFRP加固木柱的声发射能量临界指数最大似然估计曲线

Figure 13. Maximum likelihood estimation curve of AE energy critical index of CFRP-reinforced wood columns

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表 1 木材的主要力学性能指标

Table 1. Main mechanical properties of wood

Compressive strength parallel to grain/MPa	Tensile strength parallel to grain/MPa	Shear strength parallel to grain/MPa	Bending strength/MPa
39.23	51.35	4.94	67.98

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表 2 粘结剂和碳纤维的主要力学性能指标

Table 2. Main mechanical properties of impregnation adhesive and carbon fiber

Material	Elastic modulus/GPa	Tensile strength/MPa	Elongation/%
Carbon fiber	230	3700	1.8
Impregnation adhesive	2.5	40	1.5

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表 3 试件基本参数

Table 3. Specimen basic parameters

Group No.	Specimen No.	CFRP winding layers	CFRP winding angle/(°)	m/g
1	W-1	—	—	204.28
	W-2			201.36
	W-3			210.15
2	C2W0-1	2	0	218.21
	C2W0-2			221.38
	C2W0-3			215.63
3	C2W30-1	2	30	219.67
	C2W30-2			226.14
	C2W30-3			223.97
4	C2W60-1	2	60	229.36
	C2W60-2			221.04
	C2W60-3			230.43
5	C2W90-1	2	90	229.62
	C2W90-2			224.18
	C2W90-3			219.37
6	C4W90-1	4	90	239.42
	C4W90-2			245.21
	C4W90-3			236.81
Note: "W" stands for wood, "C" stands for CFRP: "W" means unreinforced wood column; "C2W30" means CFRP-reinforced wood column, with 2 winding layers and 30° winding angle; m is the mass of the specimen.

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表 4 CFRP加固木柱的轴向压缩试验结果

Table 4. Axial compression test results of CFRP-reinforced wood columns

Specimen No.	Ultimate bearing capacity/kN	Δ_max/mm	Δ_y/mm	µ
W	112.63	2.82	1.96	1.44
C2W0	124.27	2.91	1.95	1.49
C2W30	134.61	3.03	2.01	1.51
C2W60	147.25	2.97	1.88	1.58
C2W90	158.43	3.11	1.89	1.64
C4W90	161.21	3.34	1.94	1.72
Notes: Δ_max—Ultimate displacement; Δ_y—Yield displacement; µ—Displacement ductility factor.

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