Numerical simulation of residual stress field in green power metallurgy compacts by modified Drucker–Prager Cap model

Zhou, Rui; Zhang, Lianhong; He, Baiyan; Liu, Yuhong

doi:10.1016/s1003-6326(13)62744-2

Cited by 30 publications

(17 citation statements)

References 12 publications

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“…At P � 0 MPa, the residual stress in the particle and void edge attained a minimum value. Similar to the results in Figure 7, large residual stress has been observed at the contact point of adjacent particles and the spring back led to crack initiation and propagation in the compact [43].…”

Section: Node21523supporting

confidence: 84%

Particulate Scale Multiparticle Finite Element Method Modeling on the 2D Compaction and Release of Copper Powder

Li-wen

Han

Liu

et al. 2019

Mathematical Problems in Engineering

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Herein, two-dimensional (2D) single-action die compaction process of copper (Cu) powder was simulated by the multiparticle finite element method (MPFEM) at particulate scale. The initial packing structure, generated by the discrete element method (DEM), was used as an input for the FEM model, where the mesh division of each particle was discretized. The evolution of macro- and microscopic properties, such as relative density, stress distribution, particle deformation, void filling behavior, and force transmission, during compaction and pressure release processes have been systematically studied. The results revealed that the force is mainly concentrated on largely deformed regions of the particles during compaction and formed a contact force network, which hindered the densification process. In the compact, the shorter side of the large void edges rendered higher stress than the longer side. On the other hand, the stress distribution of small void edges remained uniform. After pressure release, large residual stress was observed at the contact area of the adjacent particles and the maximum stress was observed at the particles’ edges. Moreover, the residual stress did not proceed to the interior of the particles. Meanwhile, the stress of large void edges has been completely released but exhibited a nonuniform distribution. The smaller fraction of void filling resulted in a larger reduction of the released stress after pressure removal. Also, the particles closer to the upper die exhibited higher average equivalent von Mises stress inside the particles during compaction and pressure release processes.

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Section: Node21523supporting

confidence: 84%

Particulate Scale Multiparticle Finite Element Method Modeling on the 2D Compaction and Release of Copper Powder

Li-wen

Han

Liu

et al. 2019

Mathematical Problems in Engineering

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“…In addition, the size is almost equal; however, only the soft particles are under higher residual stress in the deformed part. is phenomenon is difficult to reflect in the two-dimensional forming process of composite powder [46,47].…”

Section: Compaction Process and Macroscopicmentioning

confidence: 99%

A Study of Compaction Densification Behavior of Composite Particles by Multiparticle Finite Element Method

Han

et al. 2022

Mathematical Problems in Engineering

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In this paper, 3D particulate scale modelling on the die compaction of DEM generated initial packings of both soft and hard particles was conducted by employing the multiparticle finite element method (MPFEM). The effects of initial packing structures as well as the compaction pressure on the macroscopic and microscopic properties of the whole powder mass and local structures were investigated. In addition, corresponding physical experiments were carried out for model validation. The results show that the compact obtained from the initial dense packing under vibration undergoes yielding stage earlier than that with natural initial packing (without vibration), and the relative density is much higher. Pores that are significantly smaller and with more uniform size and homogenous stress distribution are observed in the former case. Highest stress regions occur in most cases at a grain boundary with large curvature after deformation. Moreover, the high stress in the central part of both soft and hard particles during compaction is significantly reduced after pressure unloading, reaching a new force balance. In this case, the stress is concentrated mainly at the corners of the deformed particles, which creates the risk of cracking during subsequent sintering at either the contact region between particles or the corners. The numerical results are found to be in good agreement with those from physical experiments, confirming the robustness and reliability of the numerical model used in the simulations.

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“…R and α are cap eccentricity and radius of transition surface, which are closely related to the geometric shape of the cap and transition zone, respectively. Usually, α is regarded as 0.03 to obtain a smooth transition surface [25]. P a is the corresponding p value when the cap surface curve intersects the smooth transition surface curve, and can be expressed by the following equation when R is set as 0.6 [24]:…”

Section: Modified Dpc Modelmentioning

confidence: 99%

Simulation on the Direct Powder Rolling Process of Cu Powder by Drucker–Prager/Cap Model and Its Experimental Verification

Zhang

Jia

Xie

et al. 2022

Metals

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For better clarifying the influence of processing factors on the forming quality of the direct powder rolling (DPR) process, finite element simulation based on the modified Drucker–Prager/Cap (DPC) model was established and the key physical parameters of the powder were confirmed by experimental measurements. Subsequently, the effect of the main factors in the DPR process, viz., powder gradation, rolling speed and rolling gap, on the density and morphology of a green sheet were discussed by using an orthogonal experiment design followed by experimental verification. The influence of DPR parameters on the density of the green sheet is examined by a range analysis, which can reflect the sensitivity of influencing factors to the forming quality of the green sheet. The larger the range value is, the more sensitive the influencing factor is. This suggests that the quality of the green sheet is mainly influenced by particle gradation. The results show that the density of the resulting DPR green sheet with optimal parameters is mainly 7.5~8.0 g/cm3, reaches 80% of the theoretical density, and the mechanical strength can also afford the transferring process of the green sheet for the next sintering craft. The methods for modeling, obtaining physical parameters and the numerical simulation results can be used to guide rapid formation of the metal sheet by using direct powder rolling craft.

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Numerical simulation of residual stress field in green power metallurgy compacts by modified Drucker–Prager Cap model

Cited by 30 publications

References 12 publications

Particulate Scale Multiparticle Finite Element Method Modeling on the 2D Compaction and Release of Copper Powder

Particulate Scale Multiparticle Finite Element Method Modeling on the 2D Compaction and Release of Copper Powder

A Study of Compaction Densification Behavior of Composite Particles by Multiparticle Finite Element Method

Simulation on the Direct Powder Rolling Process of Cu Powder by Drucker–Prager/Cap Model and Its Experimental Verification

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