梯度灌封电路板结构的抗低速冲击性能

doi:10.12382/bgxb.2023.0949

摘要/Abstract

摘要：

灌封防护可以增强电子设备的完整性,提高对外部冲击和振动的抵抗力,在汽车、船舶和兵器等领域得到了广泛应用。但传统的均质树脂灌封材料存在韧性不足、抗冲击能力较差的问题。针对这一问题,设计了碳纳米管(Carbon nanotubes, CNT)增强树脂基梯度灌封材料,并开展梯度灌封电路板结构的抗冲击性能研究。基于准静态拉伸试验和动态落锤冲击试验分析了不同CNT含量对树脂基体的增强效果以及不同梯度类型灌封结构的抗冲击性能,并通过有限元仿真得到了灌封层及内部电路板的能量吸收和损伤失效情况。研究结果表明:添加0.7 wt% CNT的灌封材料具有较高的拉伸强度,比纯环氧树脂提高了16%;V型梯度灌封板的冲击强度和临界破坏能量高于其他梯度类型,且比均质板提高了40%和15.8%;灌封材料的缓冲吸能对内部电子元件具有良好的防护作用,并且CNT含量较高的铺层吸能更高。提出的新型梯度灌封方式为冲击环境下的电子元件的防护设计提供了参考。

关键词: 灌封防护, 梯度材料, 能量吸收, 抗冲击性能, 电路板结构

Abstract:

Encapsulating protection has been widely used in automobiles, ships and weapons. It can enhance the integrity of electronic equipment and improve the resistance to external shocks and vibrations. However, the traditional homogeneous resin encapsulating materials have insufficient toughness and poor impact resistance. In response to this issue, this paper designs the resin gradient encapsulated materials reinforced with carbon nanotube (CNT) and studies the impact resistance of gradient encapsulated circuit board structure. The enhancing effects of different CNT contents on resin matrix and the impact resistance of gradient encapsulated structures are analyzed through quasi-static tensile tests and dynamic drop hammer impact tests. The energy absorptions of different gradient layers are obtained and the damage and failure of internal circuit boards are evaluated through finite element simulation analysis. The research results show that the encapsulating material with 0.7wt % CNT exhibits a higher tensile strength, which is 16% higher than that of pure epoxy resin; The impact strength and critical failure energy of V-shaped encapsulated gradient plate are higher than those of other gradient types, and are increased by 40% and 15.8%, respectively, compared to the homogeneous plate. The buffering and energy absorption properties of the encapsulating materials have a positive impact on the protection of internal electronic components, with the gradient layer containing a higher CNT content exhibiting an increased energy absorption. The gradient encapsulation method proposed in this paper provides a reference for the protection design of electronic components under impact environment.

Key words: encapsulation protection, gradient material, energy absorption, impact resistance, electronic component

中图分类号:

朱秀芳, 周宏元, 张宏, 陈新民. 梯度灌封电路板结构的抗低速冲击性能[J]. 兵工学报, 2024, 45(11): 3879-3891.

ZHU Xiufang, ZHOU Hongyuan, ZHANG Hong, CHEN Xinmin. Low Speed Impact Resistance of Gradient Encapsulated Circuit Board Structure[J]. Acta Armamentarii, 2024, 45(11): 3879-3891.

图/表 20

图1 CNT增强EP基梯度灌封材料的制备流程

Fig.1 Preparing process of CNT reinforced epoxy resin gradient encapsulating material

表1 不同梯度类型的实验试样

Table 1 Different gradient types of test plates

图2 准静态拉伸试验

Fig.2 Quasi-static tensile test

图3 CNT增强复合材料准静态拉伸应力-应变曲线

Fig.3 Quasi static tensile stress-strain curves of CNT reinforced composite materials

图4 CNT增强复合材料动态拉伸应力-应变曲线

Fig.4 Dynamic tensile stress-strain curves of CNT reinforced composite materials

图5 PCB材料的准静态拉伸应力-应变曲线

Fig.5 Tensile stress-strain curves of PCB

图6 动态冲击试验系统

Fig.6 Dynamic impact test system

图7 不同梯度类型的冲击响应对比

Fig.7 Comparison of impact responses of different gradient types

图8 临界破坏能量下各梯度板的加速度-时间曲线

Fig.8 Acceleration-time curves of each gradient plate under critical failure energy

表2 有限元模型材料参数

Table 2 Material parameters of finite element model

CNT含量	密度/ (g·cm^-3)	弹性模量/GPa	泊松比	极限强度/MPa
纯EP	1.12	5.59	0.32	55.36
0.1%	1.12	6.06	0.32	58.47
0.3%	1.13	6.24	0.32	59.17
0.5%	1.13	6.85	0.32	67.51
0.7%	1.13	7.95	0.32	79.52
PCB	1.97	26.00	0.3	120

表3 不同CNT含量的灌封材料及PCB脆性断裂模型

Table 3 Brittle fracture model of encapsulating materials with different CNT contents and PCB

CNT 含量	输入点	断裂后直接应力/ MPa	直接断裂应变/ MPa	剪切传递系数	裂纹展开应变
纯EP	1	55.36	0	1	0
	2	0	0.013	0	0.001
0.1%	1	58.47	0	1	0
	2	0	0.015	0	0.001
0.3%	1	59.17	0	1	0
	2	0	0.019	0	0.001
0.5%	1	67.51	0	1	0
	2	0	0.021	0	0.001
0.7%	1	79.52	0	1	0
	2	0	0.023	0	0.001
PCB	1	120	0	1	0
	2	0	0.006	0	0.001

图9 灌封材料板落锤冲击试验有限元模型

Fig.9 1 Finite element model for drop-hammer impact of encapsulated plate

图10 19J冲击能量下Ⅴ型梯度板不同单元数量影响的冲击力-时间曲线

Fig.10 Force-time curves of Ⅴ-shaped gradient plate under 19J impact energy with different number of elements

图11 不同梯度类型灌封板的实验与有限元对比曲线

Fig.11 Experimental and finite element comparison curves of different gradient types of encapsulated plates

图12 各梯度灌封板的实验与仿真冲击参数对比

Fig.12 Comparison of experimental and simulated impact parameters for various gradient encapsulated plates

图13 冲击面损伤破坏形貌图(梯度V)

Fig.13 Damage and failure morphology of impact surface of plates (Gradient V)

图14 19J冲击能量下PCB中心单元的应力和应变曲线

Fig.14 Stress and strain curves of PCB central unit under 19J impact energy

图15 不同梯度类型灌封板的能量分布曲线

Fig.15 Energy distribution curves of different gradient types of encapsulated plates

图16 19J冲击能量下EP灌封板的有限元冲击模拟过程

Fig.16 Finite element impact simulation process of EP encapsulated plate under 19J impact energy

图17 22J冲击能量下灌封板V的有限元冲击模拟过程

Fig.17 Finite element impact simulation process of gradient encapsulated plate V under 22J impact energy

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