The quasi-conforming 4-node plane element (XPLAN4) with rotational degree of freedom, Enhanced Assumed Strain (XPLANE) and 8-nodes plane element (XPLANE8) are available in XFINAS.

The plane element has the plain stress, strain and axi-symmetric type. The plasticity is handled by applying the Von Mises yield condition and Prandtl-Reuss flow rule at discrete points through the plane wall. In addition, - Mohre-Column, Drecker-Prager, Tresca  Plasticity are also available. A large number of numerical testing is carried out for the validation of present XFINAS. The plane elements are in good agreement with references.

 

 

 

Example : A trapezoidal clamped beam with a unit load at the tip was analyzed, Figure 16. The new element shows a slightly faster convergence rate compared to the other elements in both stress and displacements. With a mesh of 64x64 the following solutions are obtained, v C = 23.96, ? maxA = 0.2373, ? minB = -0.2041.

 

< Fig. 17 Geometry and Material Properties >

 

 

Element

2 x 2

4 x 4

vC

smaxA

smaxB

vC

smaxA

smaxB

Q4

11.85

0.1280

-0.0916

18.30

0.1905

-0.1510

5b-I

21.13

0.1854

-0.1550

23.02

0.2241

-0.1856

QM6

21.05

0.1900

-0.1560

23.02

0.2239

-0.1850

QS6

21.06

0.1964

-0.1465

23.02

0.2263

-0.1865

8b

19.60

-

-

22.65

-

-

QI

19.27

-

-

22.61

-

-

XMEMB4

21.69

0.1923

-0.1892

23.25

0.2313

-0.2084

Ref.

23.96

0.2369

-0.2035

23.96

0.2369

-0.2035

 

< Table : Tapered and Swept Beam >

 

 

Reference

Q4 : the standard 4-node isoparametric quadrilateral.

5b-I : the 4-node hybrid stress element by Pian and Sumihara

QM6 : the incompatible Taylor et al. element.

QS6 : 4-node incompatible plane element by Hueck and Wriggers

8b : refers to the 8?(D)-PH hybrid stress plane element with drilling rotations presented by Geyer and
       Groenwood

QI : refers to the Ibrahimbegovic et al. plane element with drilling degrees of freedom.

XMEMB4 : presents XDFINAS formulation