A high-order FEM formulation for free and forced vibration analysis of a nonlocal nonlinear graded Timoshenko nanobeam based on the weak form quadrature element method

The purpose of this paper is to provide a high-order finite element method (FEM) formulation of nonlocal nonlinear nonlocal graded Timoshenko based on the weak form quadrature element method (WQEM). This formulation offers the advantages and flexibility of the FEM without its limiting low-order accuracy. The nanobeam theory accounts for the von Kármán geometric nonlinearity in addition to Eringen’s nonlocal constitutive models. For the sake of generality, a nonlinear foundation is included in the formulation. The proposed formulation generates high-order derivative terms that cannot be accounted for using regular first- or second-order interpolation functions. Hamilton’s principle is used to derive the variational statement which is discretized using WQEM. The results of a WQEM free vibration study are assessed using data obtained from a similar problem solved by the differential quadrature method (DQM). The study shows that WQEM can offer the same accuracy as DQM with a reduced computational cost. Currently the literature describes a small number of high-order numerical forced vibration problems, the majority of which are limited to DQM. To obtain forced vibration solutions using WQEM, the authors propose two different methods to obtain frequency response curves. The obtained results indicate that the frequency response curves generated by either method closely match their DQM counterparts obtained from the literature, and this is despite the low mesh density used for the WQEM systems

Medical metrology studies at Tübitak UME

Calibration and testing of medical devices are one of the most important and critical issue in metrology field. Although metrological links has been well established for measurements in technical and military field, metrology link is not powerful enough for measurements in medical field. For the medical device industry and applications in health sector, nothing counts more than the safety of a patient. Therefore all hospitals & medical equipment manufacturers have to perform periodic testing and calibration of equipments, as a quality control regimen that guarantees the reliability of medical devices. Test, measurement and calibration of bio-medical equipments is becoming increasingly significant, when accuracy in diagnosis and effectiveness in treatment is required. A feasibility study has been carried out and a report was published last year at TÜBİTAK UME (The Scientific and Technological Research Council of Turkey, National Metrology Institute) in order to outline the current situation in the country. A five year roadmap and a a plan were programmed for providing of reliability and metrological traceability in medical measurements. Medical metrology research laboratory has been established and a number of medical device design projects were initiated