Research Areas
1. Inelastic Analysis of Materials and Structures
Formulation and application of constitutive models for inelastic
material behaviour with emphasis on cyclic, creep, and damage effects.
In particular a multi-surface model of anisotropic hardening was
proposed with account for memory effects in cyclic loading programs. A
modified versions of this models were used in analysis of creep or
creep-plasticity interaction problems. Various model of this type are
actually being used in computer systems of inelastic analysis of
structures. Similarly, for soils, the description of deformation
processes was proposed and applied to simulate cyclic behaviour of
soils, including liquefaction effect. The material damage theory
applied to rock materials was used in description of rock burst
phenomena accounting for rate-dependent damage accumulation.
2. Optimal Design and Sensitivity Analysis of Structures
Uniform variational approach was developed for both sensitivity
analysis and optimal design problems with numerical algorithms based on
optimality criteria. A wide class of optimal design problems was
treated including material, shape, support, loading, and size variables.
The non-linear structure response due to physical effects and
large displacements was considered in regular and critical states and
the relevant design method was developed accounting for the admissible
imperfection level. Topology, shape and material design methods were
developed using the concept of sensitivity forces driving the design
process to proper optimal solutions.
3. Models of friction, slip and wear at contact interfaces.
The slip, wear and friction rules at material interfaces were
analyzed accounting for dilatancy, anisotropy, and two scale asperity
interaction. The memory rules for progressive and reverse slip events
were incorporated by following the multi-surface plasticity concepts.
Both damage and fracture accompanied by friction were considered. The
constitutive models can be applied to interfaces in elastic regime and
in plastic regime when plastic flow of asperities occurs combined with
adhesive and abrasive effects, typical for metalworking processes. The
progressive damage of thin layers was analyzed accounting for cracking
and frictional slip at contact for both monotonic and cyclic loading.
Publications
About 400 technical papers in international or national journals
and conference proceedings. Authorship or co-authorship of 11 books and
10 unpublished research reports.