Investigation on the creep-age forming of an integrally-stiffened AA2219 alloy plate: experiment and modeling

Yang, Youliang; Zhan, Lihua; Shen, Rulin; Jian, Liu; Li, Xicai; Huang, Ming‐Hui; He, Diqiu; Chang, Zhilong; Ma, Yunlong; Wan, Li

doi:10.1007/s00170-017-1248-3

Cited by 15 publications

(10 citation statements)

References 20 publications

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“…While for integrally stiffened structures, high stress is more likely to be concentrated around the bending stiffeners [21], which can not only increase creep strain accumulations but also accelerate the precipitation progress of the material in the stiffeners [22]. Therefore, mechanical strength is also a key factor to be considered for CAFed stiffened panels [23].…”

Section: Introductionmentioning

confidence: 99%

An investigation of creep age forming of AA7B04 stiffened plates: Experiment and FE modelling

Lyu

Huang

et al. 2019

Journal of Manufacturing Processes

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Creep age forming (CAF) of aluminium alloy 7B04 (AA7B04) stiffened plates has been experimentally and numerically investigated in this study. Creep-ageing experiments of AA7B04-T651 were conducted under different tensile stress levels at 140 °C for up to 20 h, and a set of unified constitutive equations was calibrated based on the experimental results of the evolutions of creep strain, yield strength and precipitate size, which was implemented into ABAQUS for CAF process modelling. CAF experiments and corresponding simulations of AA7B04 stiffened plates were then carried out and the effect of stiffener height and die radius on springback and yield strength was studied. It was found that the springback percentage decreases with increasing stiffener height and decreasing forming die radius, and the yield strength is slightly lower in the stiffener than in the skin of the CAFed stiffened plates due to stress effect on ageing progression. A good agreement has been achieved between experimental and corresponding FE results, with maximum deviations of 6.7% and 3.3% respectively for springback and yield strength.

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Section: Introductionmentioning

confidence: 99%

An investigation of creep age forming of AA7B04 stiffened plates: Experiment and FE modelling

Lyu

Huang

et al. 2019

Journal of Manufacturing Processes

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“…For CAF process, material constitutive models and FE simulation models for various aluminium alloys, e.g., Al-Cu-Mg [20], Al-Zn-Mg [21], Al-Cu-Li [22] and Al-Mg-Si [23], have been well developed to achieve high precision springback prediction. Conventional DA method assisted by FE simulation is applicable for tool design in CAF process, but will suffer from the low convergence speed.…”

Section: Introductionmentioning

confidence: 99%

“…The corresponding plastic strain in the plate after loading then can be obtained as: After the stress-relaxation stage of CAF, part of the loaded stress will be relaxed and some elastic strains will be converted to creep strains. The creep-ageing/stress-relaxation behaviour of various aluminium alloys has been investigated and modelled by some previous studies [20,21]. It can be concluded that creep strain (ε c1 ) generated during stress-relaxation is mainly determined by the stress-relaxation time t and applied stress level σ 0 (z) for a particular material, as:…”

Section: Introductionmentioning

confidence: 99%

An accelerated springback compensation method for creep age forming

Rong

Shi

et al. 2018

Int J Adv Manuf Technol

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Springback compensation is essential for tool design in creep age forming (CAF) process. In this study, a new accelerated springback compensation method integrating springback mechanism of a plate with creep-ageing behaviour of materials has been developed for CAF tool design to manufacture both singly and varyingly curved products. Springback compensation curves that relate the objective shapes and springback compensated shapes by their curvature, stress and strain states have been established, based on the numerical solution of springback behaviour of CAF process. For singly curved products, a one-step springback compensation method is proposed with reference to the springback compensation curves, and its effectiveness has been demonstrated by CAF test with a peak-aged aluminium alloy AA6082-T6. For products with varying curvatures, an accelerated method is developed for CAF tool design by integrating springback compensation curves with finite element (FE) assisted displacement adjustment techniques. The new accelerated method can significantly improve the tool design efficiency for CAF process when compared with conventional displacement adjustment techniques and has been verified by CAF manufacture of a varyingly curved product with AA6082-T6 material. The new accelerated springback compensation method developed in this study can be used for efficient tool design for CAF process of various products.

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“…Lam et al [17] studied the effect of different rib stiffener designs on the springback of 2219 aluminum alloy ribbed panel in CAF, and found that the highest elastic stress is more likely to occur within and around the bending rib, taking up a greater proportion of the creep strain. Yang et al [18] investigated the CAF of pre-deformed 2219 aluminum alloy ribbed panel by experiment and modeling, and pointed out that the final shape of the panel that was contributed from plastic deformation and creep deformation concurrently, with corresponding percentages of 33% and 67%, respectively. Although above studies have been carried out on the effects of the complex structures of ribbed panels, there are less reports aimed at the creep damage that is caused by stress concentration and inhomogeneous deformation.…”

Section: Introductionmentioning

confidence: 99%

Damage in Creep Aging Process of an Al-Zn-Mg-Cu Alloy: Experiments and Modeling

Lei

et al. 2018

Metals

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In creep age forming (CAF), large integral panel components of high-strength aluminum alloy can be shaped and strengthened under external elastic loading at an elevated temperature through creep deformation and age hardening, simultaneously. However, the high ribbed structure on panel may induce stress concentration, inhomogeneous plastic deformation and even damage evolution on the bending rib, leading to the difficulty in controlling forming precision and material properties. Therefore, the generation and evolution of damage are necessary to be considered in the design of CAF. Taking 7050 aluminum alloy as the case material, the continuous and interrupted creep aging tests at 165 • C and three stress levels (300, 325, and 350 MPa) were conducted, and the corresponding material properties, precipitate, and damage microstructures were studied by mechanical properties tests, transmission electron microscope (TEM) and scanning electron microscope (SEM) characterizations. With the increase of stress level, the creep deformation occurs easier, the precipitates grow up faster, the creep damage occurs earlier, the growth rate and the size of microvoids increase, the mechanical properties decrease more rapidly, and the dominant mechanism of creep fracture changes from shear to microvoid coalescence. To simulate creep aging behavior with damage, a continuum damage mechanics (CDM) based model is calibrated and numerically implemented into ABAQUS solver via CREEP subroutine. The CAF of 7050 aluminum alloy panels with different height ribs were conducted by experiment and FE simulation. The forming process presents a typical stress relaxation phenomenon. The creep damage mainly occurs on the bending rib due to the severe stress concentration. With the increase of rib height, the creep strain and damage degree increase, but the springback decreases.

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Investigation on the creep-age forming of an integrally-stiffened AA2219 alloy plate: experiment and modeling

Cited by 15 publications

References 20 publications

An investigation of creep age forming of AA7B04 stiffened plates: Experiment and FE modelling

An investigation of creep age forming of AA7B04 stiffened plates: Experiment and FE modelling

An accelerated springback compensation method for creep age forming

Damage in Creep Aging Process of an Al-Zn-Mg-Cu Alloy: Experiments and Modeling

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