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Experimental and simulation study on stiffness of basalt fiber-reinforced plastic door interior trimming panel

Yao Yuanheng, Wang Shaoluo, Xu Liwang, Jiang Hao, Gu Yongqiang, Li Guangyao, Cui Junjia

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e53, 2023

EN

Basalt fiber-reinforced polypropylene composites have been widely used in industrial production for lightweight designs owing to their low price, good mechanical properties and environmental friendliness. In this study, the automotive door interior trimming panel composed of basalt fiber (BF) reinforced polypropylene (PP) was prepared by injection molding. The effects of BF on the stiffness of PP automotive door interior trimming panels were studied by experiment and simulation. The indentation test was carried out by digital image correlation (DIC) technology. The finite element simulation (FES) was conducted and the result was compared with that of experiment to verify the accuracy of the FES. Then, the stiffness test and the FES of the automotive door interior trimming panels were implemented to study the effect of basalt fiber on the stiffness of polypropylene. Furthermore, the thickness of the automotive door interior trimming panel was optimized by stiffness simulation. The results showed that the indentation test had a great agreement with the FES results. The addition of BF could effectively improve the stiffness of polypropylene plastic automotive interior panel. The BF-reinforced polypropylene plastic automotive door interior trimming panel with a thickness of 1.0 mm had the same stiffness with polypropylene plastic automotive door interior trimming panel with a thickness of 2.4 mm.

2

Influence of adhesive on dynamic performance of steel/Al electromagnetic clinched joints

Liao Yuxuan, Zhong Jiabao, Li Guangyao, Cui Junjia, Jiang Hao

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e177, 2022

EN

In this paper, the dynamic behavior of clinched, bonded and clinch-bonded joints for steel/Al was investigated. Three tensile speeds (1 m/s, 5 m/s, and 10 m/s) were selected. The strain evolution of three kinds of joints was analyzed by the digital image correlation (DIC) technique. The mechanical properties and failure mechanism of joints were obtained. The result showed that the shear strength and energy absorption of joints were both increased as the tensile speed increased. When the tensile speed increased from 1 to 10 m/s, the peak loads of clinched joints, bonded joints and clinch-bonded joints were increased by 26.7%, 17.5% and 16.3%, respectively. The energy absorption of three kinds of joints were increased by 35.4%, 27.3%, and 29.0%, respectively. Besides, the addition of adhesive effectively improved the shear strength and energy absorption of the joint compared to clinched joints. Specifically, the peak load and energy absorption were increased by nearly three times and thirteen times, respectively. The failure modes of clinched joint ranged from mixed failure to neck failure. While the failure modes of bonded joint were mixed failure at different tensile speeds. For clinch-bonded joint, the failure modes of interlock structure were the neck failure and the failure modes of adhesive layer were mixed failure. With the increase of the tensile speed, the cohesive failure area of bonded joint and clinch-bonded joint decreased, and the damage degree of mechanical interlock was more serious for clinched joint.

3

AA5052 failure prediction of electromagnetic flanging process using a combined fracture model

Deng Huakun, Mao Yunfei, Li Guangyao, Zhang Xu, Cui Junjia

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e84, 1--17

EN

Electromagnetic forming process could significantly increase the forming limit of aluminum alloy. However, high-speed fracture prediction of aluminum alloys is a major problem in the development of electromagnetic flanging process. In this study, notched specimen tensile tests with high-speed Digital Image Correlation system were conducted under the strain rate range from 0.001 to 100 s-1. A fracture model of AA5052 alloys which combined of an uncoupled fracture model, Gissmo damage evolution model and Johnson-Cook strain rate effect was established. Electromagnetic flanging experiments were conducted to verify the failure criteria effectiveness. Results showed that failure strain was significantly influenced by strain rate under various loading path. Compared with the experiments, the percentage error of established electromagnetic flanging process FEM model was less than 4%. The fracture model established could well predict notched specimen high-speed failure, and also accurately predict sheet failure model of electromagnetic flanging experiments and, thus, verified the effectiveness of the established dynamic failure criteria in electromagnetic flanging process.

4

Mechanical properties and corrosion behavior of galvanized steel/Al dissimilar joints

Jiang Hao, Liao Yuxuan, Jing Lijun, Gao Song, Li Guangyao, Cui Junjia

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 4

555--567

EN

In this paper, the mechanical properties and corrosion behavior of steel/Al electromagnetic self-pieced riveting, adhesive and hybrid riveted and adhesive joints in the salt-spray environment were compared. These joints were firstly placed in the neutral salt spray environment, and then surface observation, weighting, mechanical properties tests and fractographic analysis were conducted. Results showed that with the increase of ageing time, the peak load of the single riveted joints firstly increased and then decreased, while the peak loads of the other two joints continued to decline. This was because the corrosion products formed in the sheet clearance of the single riveted joint, increasing the frictional resistance during the shear process after a short ageing time (before 20 days). For adhesive and hybrid joints, adhesives prevented the formation of corrosion products in the clearance, but it was vulnerable to damage by chloride ions, which would result in the continuous strength degradation of the joints. Specifically, after ageing for a long time (25 days), the peak load of the riveting, adhesive and hybrid joints, respectively, decreased by 11.2%, 26.3% and 14.4% comparing with the uncorroded joint, which showed the adhesive joint had the worst corrosion resistance. This indicated that the adhesive joint was more affected by environmental factors than the riveted and hybrid joint.

5

Adiabatic shearing mechanism on Al-4.2%Cu alloy bars subjected to electromagnetic loading

Zhang Xu, Huang Yunkai, Meng Shengfei, Zhu Congcong, Li Guangyao, Cui Junjia

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

393--405

EN

This paper proposed an electromagnetic loading process with the high-speed impact. Al-4.2% Cu alloy bars were used to employ electromagnetic impact (EI) experiments. Deformation mechanism and microstructure evolution of EI samples were revealed by theoretical model and microstructure characterizations. The EI process had impact force (peak value 40 kN) and impact velocity (peak value 6.7 m/s) during a short time period (1.25 ms). Adiabatic shearing mechanism dominated the whole deformation process, causing that significant microstructure characteristic was adiabatic shear bands (ASBs). The theoretical analysis implied that the formation of ASBs was accounted for the radial velocity gradient. Most plastic deformations concentrated in ASBs, and approximately pure shear deformations resulted in adiabatic temperature rise of 0.33–0.42 Tm inside ASBs. The width of ASBs was about 135 μm, in which original equiaxial grains were elongated into laminated sub-structures. TEM observations showed multi-slip systems were simultaneously actuated due to severe shear deformations. High dislocation density and dislocation tangles distributed with the ASBs. Adiabatic temperature rise and distorted energies drove sub-grains rotate into recrystallization grains (70–280 nm) with large angle grain boundaries. The needed maximum time (45 μs) for rotational dynamic recrystallization was far less than that of plastic deformation, indicating that rotational dynamic recrystallization mechanism contributed to the formation of recrystallization grains.

6

Numerical and experimental study on high-speed nailing process for aluminum/steel structures induced by electromagnetic impact

Cui Junjia, Li Bingkun, Jiang Hao, Li Guangyao

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 2

366--379

EN

The innovation of traditional machinery manufacturing and the promotion of advanced manufacturing technology are becoming the booster for the sustainable development of automobile industry. This paper aims to propose a promising manufacturing technology driven by electromagnetic impact, which is called as electromagnetic high-speed nailing. In this paper, the connection mechanism and joint performance (e.g., microtopography and mechanical properties) of the aluminum alloy 5052 (Al)/high-strength steel DP590 (HSS) structure were studied using simulation and experiment methods. A two-dimensional axisymmetric model based on mechanical–thermal finite element analysis was proposed to explore the formation process of the joints. Microscopic observations and effective plastic strain field analysis showed that excessive deformation of the Al sheet caused serious damage to the HSS sheet, thereby making the joint more susceptible to failure. Through mechanical properties tests, it was found that the mechanical properties of the joints with different discharge energies varies. Specifically, the joints at the discharge energy of 5.3 kJ had the highest maximum shear load. While the joints at the discharge energy of 5.1 kJ showed higher push-out strength because of the better wrapping and higher interlocking degree.

7

Investigations on mechanical properties and microtopography of electromagnetic self-piercing riveted joints with carbon fiber reinforced plastics/aluminum alloy 5052

Liang Jusong, Jiang Hao, Zhang Jinsheng, Wu Xianhe, Zhang Xu, Li Guangyao, Cui Junjia

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

240--250

EN

In this paper, the mechanical properties of electromagnetic self-piercing riveted (E-SPR) joints with carbon fiber reinforced plastics (CFRP)/aluminum alloy (Al) 5052 were comprehensively investigated. Microtopography observations, hardness measurements and tensile-shear strength tests were performed by comparing with regular pressure self-piercing riveted (P-SPR) joints. Results showed that the undercut value of E-SPR joints was higher than that of P-SPR joints. The hardness values on rivet legs of E-SPR joints were larger and almost no difference on rivet heads between the E-SPR and P-SPR. In addition, it was found that mechanical properties of E-SPR joints were higher than that of P-SPR joints. The shear fracture appearance indicated that E-SPR joints with higher undercut were more difficult to rupture in the bottom of Al sheet.

8

Influence of electromagnetic riveting process on microstructures and mechanical properties of 2A10 and 6082 Al riveted structures

Dong Dongying, Sun Liqiang, Wang Qiong, Li Guangyao, Cui Junjia

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1284--1294

EN

Electromagnetic riveting (EMR) technology had unique connection advantages compared to traditional riveting methods. The influence of EMR process on microstructures and mechani- cal properties for 2A10 and 6082 aluminum riveted structures was investigated by comparison with regular pressure riveting (RPR) process. The microstructures and mechanical properties of the two riveting processes were analyzed by optical microscopy and tensile testing machine, respectively. The micro-hardness and the interference amount were also investi- gated. The results showed that the main characteristic of the driven head was the shear zone. The grain deformation of the EMR in shear zone was more severe than that of the RPR. The width of the shear zone of the RPR was larger than that of the EMR. The trend of micro- hardness distribution was opposite along the direction of the shear zone. Meanwhile, the distribution of the interference amounts of EMR had a better uniformity. The failure mecha- nisms of shear tests of the EMR and RPR were same, but the pull-out tests were different. The dynamic loading had a great influence on the microstructures and mechanical properties of riveted structures, and the mechanical properties of EMR were significantly enhanced.