This paper discusses modern FEA-driven simulation procedures used in design of structural load-carrying parts. The focus of the paper is on topology optimization usage within the context of two currently very interesting topics: configuration and optimization of lattice structures and modern additive manufacturing technologies. The discussion is enriched by numerical examples and experimentally obtained results.
B.06 Other
COBISS.SI-ID: 18962454The recent performed on-line monitoring of strain in pillar’s legs of transmission line shows correlation between weather conditions, temperature of air and temperature of conductor vs. length of conductor, sag and change of tensile force in conductor. The new study has been suggested by Slovenian operator for high voltage electrical energy provider. The study is dealing with change of deformation in legs of pillars. The boundary conditions are obtained by experimental measurement of strain in legs and geometrical measurement of all three conductors between two pillars. The performed study shows that online monitoring of change strain can be connected with change of geometry of conductors and consequently the change of tensile force in conductor. The change of tensile force in conductor can be caused by additional weight or temperature change. The verification of model requires additional measurement of conductors geometry at least three different temperature including parallel measurement of strain in legs.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 18736406Components and structures exposed to elastic dynamic loading respond with elastic strains on the surface of the material. Mechanical response could be monitored by deformations on the surface. The measurements and monitoring of these parameters could be performed with electronic devices for on-line measurements, controlled by computerized systems. Fatigue induced flaw growth was monitored on a 4-point specimen, loaded by cyclic dynamic bend forces. The flaw growth was monitored by strain gauges with standard resistance of 120Ω. After performance of fractal-graphical measurements, a flaw growth analysis was performed to determine the shape, propagation and cross sections of the crack. To determine the stress intensity factor a numerical model was developed based on measured crack shapes, material properties and cyclic loading data of the actual tested specimen. The investigation results showed that the derived calibration curve could be used to predict surface deformations as a result of crack propagation and growth, but not crack initiation. With the determination of surface deformation, one could follow the crack transition from semielliptical surface crack to through thickness crack. The stress intensity factor has been determined numerically by using Finite element method for five different fatigue crack fronts. Results show that fatigue crack on the surface of specimen propagated under almost constant stress intensity factor value. Consequently, in our case, the fatigue crack growth rate was constant during transition from surface semi-elliptical crack to through thickness crack front. The aim of this paper is to describe methodology and results based on experimental and numerical modeling during crack propagation and potential use of this technique for online monitoring purposes.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 18798358Since the late thirties of the former century, Strain gauge is a renowned device for the stress-strain measurements on a different kinds of structures. There is a great variety of Strain gauges on the market and despite that fact, usually some specific application requires a unique solution. Far the most frequently, such cases are related to Strain gauge mounting on coarse, hardly accessible or inaccessible surfaces. Methodology proposed by this paper involves a deformeter, actually a pre-formed resilient piece of metal with attached Strain gauge. Commercially, various types of deformeters are available on the market. They are described in the available literature. Usually a minimal span of such deformeter is 50mm or greater. Therefore for a shorter span a dedicated deformeter must be developed. In order to design a multipurpose, widely applicable linear deformeter, with adaptable span, a new concept of Ω form is explored. This paper describes a research and development effort, invested into creation of a new type of deformeter. The design process started with 3D modelling of different Ω forms. Among several drafted shapes an optimal form is selected. Based on a 3D modelling outcome, a prototype of a spring strip is shaped and thermally treated. After that, Strain gauges are bonded to Ω deformeter and the model is justified in the Lab conditions. A very high degree of compliance is achieved with the invented solution, providing operation in a wide stretching range (0 – 5 mm) including prominent stability under different ambient conditions.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 19081494