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FEM CST Plane Element

Constant Strain Triangle · B matrix (strain-displacement) · Constitutive matrix D · Ke = t·A·BᵀDB · Plane stress / plane strain

Element Parameters

Node coordinates:

Results

Element area A (m²)—
Plane type active—

Citations

Cook §6.2-5B=(1/2A)·[b₁ 0 b₂ 0 b₃ 0; 0 d₁ 0 d₂ 0 d₃; d₁ b₁ ...] where bᵢ=yⱼ-yk, dᵢ=xk-xⱼ
Cook §6.2-11Ke=t·A·BᵀDB — element stiffness (constant over element)
VerifyUnit right triangle (0,0),(1,0),(0,1): A=0.5, B[0][0]=-1, B[0][2]=+1 ✓

← Beam Frame →

B Matrix (3×6 — strain-displacement)

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D Matrix (3×3 — constitutive)

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Ke Matrix (6×6 — element stiffness)

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Preliminary educational tool. Verify results against textbook solutions.