arXiv subjects

Run Du

Publications and source records attributed to Run Du.

2 recordsLinked to original sources

arXiv2026

Element-dependent buckling loads of stiffened panels under cantilevered shear

The linearized buckling load of a stiffened panel depends on the stress stiffness its shell element assembles. We read it from exported operators against three truncations of one second variation. The classic pass of ANSYS SHELL181 carries a rotation-rotation block pairing the drilling freedom with the bending rotations and its perturbation pass does not; removing the block recovers the perturbation load factor to 0.02%. SHELL281 carries block and couplings in both passes. Abaqus S4 matches the critical mode of the complete second variation to 1.0000 on the translations and its load factor to 1.7%, against 17% and 34% for the other two forms. On an optimized panel under cantilevered shear a 20-node continuum lies 3% to 6% above that form, S4 and SHELL281, 11% and 23% below both SHELL181 passes and 25% above Abaqus S8R, at the finest meshes. On a conventionally stiffened panel the SHELL181 passes stand 1.0% and 3.5% above the complete form, 9% and 21% at half the rib pitch; under a shear flow, on cylinders, open beams and under axial compression the three forms coincide and no pass parts by more than 0.3%.

cs.CE↗

arXiv2026

Overlap-free multi-material topology optimization for minimum compliance in two and three dimensions by level-set-based negative-mapping interpolation

To address challenges such as gray elements and material overlaps, this paper extends the level set-based negative-mapping interpolation method to the multi-material proportional topology optimization of macro-scale structures in two and three dimensions. The approach utilizes an alternating active-phase algorithm to decompose M-phase problems into simplified two-phase subproblems described by level set functions. By integrating an evolutionary strategy, the method circumvents complex sensitivity calculations. A negative-mapping interpolation then removes the material overlaps at the interfaces. Numerical experiments on 2D cantilever and MBB beams and on a 3D cantilever beam demonstrate that the present method eradicates gray elements, produces smooth boundaries and ensures overlap-free material distributions at a compliance comparable to that of the classical SIMP method, lower than the SIMP value in four of the eight two-dimensional test cases and higher by 0.3%, 0.4%, 4.8% and 12.7% in the other four; the influence of the material properties, of the interface treatment and of the number of iterations on the results is also discussed.

cs.CE↗