An analytical/numerical method for determining the strain rate intensity factor in axisymmetric flow and its use to predict the formation of a hard surface layer in extrusion.

Project leader's name
Nguyen Manh Thanh
Research hosting institution
Institute of Mechanics
Project duration
2016 - 2018
Scientific field(Program)
NGA
Members
́Project’s budget
200 million VND
Classify
Pass
Goal and objectives of the project

The objective of the project is to develop an analytical/numerical method for determining the strain rate intensity factor in axisymmetric flow and its use to predict the formation of a hard surface layer in extrusion.

Main results
  1. A numerical solution for compression of an axisymmetric plastic tube on a rigid fibre has been constructed. (stress and velocity fields, distribution of the strain rate intensity factor on the maximum friction surface).
  2. It was confirmed that the numerical solution of the strain rate intensity factor (D-factor) in the compression of an axisymmetric plastic tube on a rigid fibre will tend to the numerical solution of D-factor in the Prandtl’ problem (for the plate with the same length 2L and thickness H = 2(a - b)) when the thickness - radius ratio (a - b)/a decreases to zero.

Some images of the project: 

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Novelty and actuality and scientific meaningfulness of the results

This is the first time that the method of characteristics has been used to construct a numerical solution for compression of an axisymmetric plastic tube on a rigid fibre (with the major results listed in item 10). Unlike the semi-analytical solutions published, the numerical solution completely satisfies the exact boundary conditions of the problem.

Products of the project

- Publications:
E. A. Lyamina, Thanh Nguyen. Effect of the yield criterion on the strain rate and plastic work rate intensity factors in axisymmetric flow. Structural Engineering and Mechanics, Vol. 58, No. 4 (2016) 719-729.

  1. Thanh Nguyen, Kien Nguyen, Sergei Alexandrov. A numerical solution for the axisymmetric flow of a plastic tube on a rigid fibre. Journal of Physics: Conf. Series 885 (2017) 012018. The 6th International Conference on Manufacturing Engineering and Process, 27–29 May 2017, Lisbon, Portugal. 1-8.
  2. Nguyễn Mạnh Thành, Nguyễn Trung Kiên và Nguyễn Minh Tuấn. Xây dựng các phương trình dọc theo đường đặc tính cho bài toán dẻo đối xứng trục ở chế độ tương ứng với mặt σ1 ̶ σ3 = 2k ; σ1 > σ2 > σ3 của lục lăng Tresca và luật Liên kết dòng chảy (Associated flow law). Hội nghị Cơ học toàn quốc lần thứ X, Hà Nội, 8-9/12/2017.

- Patents:
- Products (description...):
- Other products:

Recommendations
  • With an adjustment related to the study content No. 3 (in the approved proposal), the Vietnamese team has completed all the contents of the Vietnam-Russia bilateral project 2016- 2017.
  • It is necessary to continue in-depth studies on large plastic deformation to consolidate and advance the knowledge and experience accumulated by the Vietnamese side in the process of accomplishing this Project in order to achieve better research results.

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