Same initials. Two dissertations. One sparse graph.

A public lab for a private joke

Radek Varga wrote a discrete-element method with Timoshenko beam bonds. Richard Vondracek wrote the blocked sparse direct solver that still lives in OOFEM as DSS. Both sign their work RV, and HiStruct is the third particle: the support that takes the rigid-body modes so this page can sit on the public internet without floating away.

In the picture, the two RV spheres are indistinguishable until you look at the bonds. The small one at the bottom is the host. Without it the system is singular. We thought that was funny enough to print.

Static site. No backend. GPU later, maybe. Hosted with HiStruct’s blessing.

Varga · Vondracek · HiStruct

Discrete-element lab

Beam-bond DEM in the browser, factored with DSS. Client-side JavaScript only.

equations: —
residual: —
factor: —

Specimen

Kind

n_x n_y n_z

Bond neighbourhood Bond strength σ_lim (Pa), 0 = elastic

DSS

Ordering Linear solver

Thesis block is Varga Table 3.2: 2.0×0.6×0.6 m, 266 particles, ΣF_x = −10 kN on the right face. The strip above the view reports applied force, support reaction, equilibrium imbalance, loaded-face displacement, internal energy, and the diagonal Δt_crit. The slider ramps that load. σ_lim > 0 deletes overstressed bonds and refactorizes.

Solver log

From small to larger DOF

case	N_p	neq	nnz(K)	L blocks	kB	sym ms	factor ms	solve ms	rel. res.	u min