Thermally Assisted Self-Piercing Riveting of AA6061-T6 to Ultrahigh Strength Steel

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Lin Deng ◽  
Ming Lou ◽  
Yongbing Li ◽  
Blair E. Carlson
Keyword(s):  
Experimental System ◽  
Mechanical Tests ◽  
Heating Time ◽  
Vehicle Body ◽  
Inductive Heating ◽  
Lap Shear Strength ◽  
Heating Current ◽  
Ultrahigh Strength ◽  
Ultrahigh Strength Steel ◽  
Lap Shear

Self-piercing riveting has been widely used in vehicle body manufacturing to join aluminum alloys or aluminum to steel. However, it is difficult to rivet ultrahigh strength steel (UHSS) because of its resistance to piercing of the rivet. In this paper, a thermally assisted self-piercing riveting (TA-SPR) process was proposed to improve riveting of the UHSS, through locally preheating the UHSS sheet using an induction coil prior to the traditional self-piercing riveting (SPR) process. An experimental system consisting of inductive heating apparatus, conventional self-piercing riveting equipment, and coupon transfer mechanism was established and the steps, e.g., preheating, coupons transfer, and riveting, were automatically conducted at preset schedules. Based on experiments with this system, the effects of heating current, heating time, and coil heating distance on riveting of AA6061-T6 and DP980 were examined systematically by metallurgical analyses and mechanical tests. It was found that an appropriate combination of heating current and heating time, e.g., 0.5 s at 600 A, could produce crack-free joints having 77.8% higher undercut and 24% higher lap-shear strength, compared with results obtained using a conventional SPR process.

Thermally Assisted Self-Piercing Riveting of Aluminum AA6061-T6 to Ultra-High Strength Steels

2018 ◽  
Author(s):  
Lin Deng ◽  
Ming Lou ◽  
YongBing Li ◽  
Blair E. Carlson
Keyword(s):  
High Strength Steels ◽  
Experimental System ◽  
High Strength ◽  
Mechanical Tests ◽  
Heating Time ◽  
Vehicle Body ◽  
Inductive Heating ◽  
Heating Current ◽  
Lap Shear ◽  
Ultra High Strength Steels

Self-piercing riveting has been widely used in vehicle body manufacturing to join aluminum alloys or aluminum to steel. However, it is difficult to rivet ultra-high strength steel (UHSS) because of its resistance to piercing of the rivet. In this paper, a thermally assisted self-piercing riveting (TA-SPR) process was proposed to improve riveting of the UHSS, through locally preheating the UHSS sheet using an induction coil prior to the traditional self-piercing riveting (SPR) process. An experimental system consisting of inductive heating apparatus, conventional self-piercing riveting equipment and coupon transfer mechanism was established and the steps, e.g., preheating, coupons transfer and riveting, were automatically conducted at preset schedules. Based on experiments with this system, the effects of heating current, heating time and coil heating distance on riveting of AA6061-T6 and DP980 were examined systematically by metallurgical analyses and mechanical tests. It was found that an appropriate combination of heating current and heating time, e.g., 0.5s at 600A, could produce crack-free joints having 77.8% higher undercut and 24% higher lap-shear strength, compared to results obtained using a conventional SPR process.

scholarly journals MECHANICAL PROPERTIES OF CARBON NANOTUBES-MODIFIED EPOXY GROUT FOR PIPELINE REPAIR SYSTEM

2019 ◽  
Vol 81 (3) ◽  
Author(s):  
Hanis Hazirah Arifin ◽  
Nurfarahin Zainal ◽  
Libriati Zardasti ◽  
Nordin Yahaya ◽  
Lim Kar Sing ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Mechanical Tests ◽  
Repair System ◽  
Dispersion Process ◽  
Lap Shear Strength ◽  
Lap Shear ◽  
Roll Mill ◽  
Infill Material ◽  
Modified Epoxy

Epoxy grout properties are theoretically important in predicting the behaviour of the composite pipeline repair system. Usually, it is used as an infill material to fill the gap or irregularity on the surface caused by pipe corrosion and ensures a smooth bed before fibre wrapper can be applied to recover the pipeline strength. In this research, the existing commercially available epoxy resin grout has been strengthened by using Carbon Nanotubes (CNTs) at the amount 0.1% of weight fractional to evaluate their apropos behaviour to the neat epoxy grout. The various mechanical tests were performed on this modified grout to identify its compression, tensile, flexural and lap shear strength. In addition, the dispersion process of CNTs was carried out by using ultrasonication and three-roll mill technique to ensure an optimum enhancement in the properties of the polymer matrix. By comparing the strength, 0.1% of CNTs filler has significantly improved the strength of grout in flexural, tensile and shear bonding but not in compression. In addition, the results also indicate that CNTs filler has increased the modulus of elasticity of the infill material. Therefore, it demonstrates the intrinsic potential of the CNTs in modifying the properties of the epoxy grout.

Mechanical properties of multiwall carbon nanotubes/unidirectional carbon fiber-reinforced epoxy hybrid nanocomposites in transverse and longitudinal fiber directions

2021 ◽  
pp. 096739112098651
Author(s):  
Saeedeh Saadatyar ◽  
Mohammad Hosain Beheshty ◽  
Razi Sahraeian
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Epoxy Resin ◽  
Interlaminar Shear Strength ◽  
Lap Shear Strength ◽  
Transverse Tensile ◽  
Lap Shear ◽  
Longitudinal Fiber ◽  
Interlaminar Shear ◽  
Multiwall Carbon

Unidirectional carbon fiber-reinforced epoxy (UCFRE) is suffering from weak transverse mechanical properties and through-thickness properties. The effect of different amount (0.1, 0.3 and 0.5 phr which is proportional to 0.09, 0.27 and 0.46 wt%, respectively) of multiwall carbon nanotube (MWCNT), on transverse tensile properties, flexural strength, fracture toughness in transverse and longitudinal fiber directions, interlaminar shear strength and lap shear strength of UCFRE has been investigated. Dicyandiamide was used as a thermal curing agent of epoxy resin. MWCNT was dispersed in the epoxy resin by ultrasonic instrument and their dispersion state was investigated by scanning electron microscopy (SEM). The curing behavior of epoxy resin and its nanocomposites was assessed by differential scanning calorimetry. Results show that transverse tensile strength, modulus and strain-at-break were increased by 28.5%, 25% and 14%, respectively by adding 0.1 phr of MWCNT. Longitudinal flexural properties of UCFRE was not changed by adding different amount of MWCNT. Although longitudinal flexural strength was increased by 5% by adding 0.1 phr of MWCNT. Fracture toughness in transverse and longitudinal fiber directions was increased by 39% and 9%, respectively at 0.3 phr of MWCNT. Results also show that interlaminar shear strength and lap shear strength were increased at 0.3 phr of MWCNT by 8% and 5%, respectively. These increases in mechanical properties were due to the good adhesion of fibers to the matrix, interlocking and toughening action of MWCNT as revealed by SEM.

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