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AbstractIn modern lightweight construction, multi-material design has become increasingly important. An increasing number of structures are being adhered because adhesive joining technology can be used regardless of the material of the bonded partners. Owing to the dissimilar coefficients of thermal expansion, thermally induced relative displacements of the adherend occur during heat curing. Following these pre-deformations, changes in the mechanical properties of adhesive joints were observed. In this study, thick adherend shear specimens were used to induce defined relative displacements in the shear plane during the curing process. Quasi-static tests showed a directional dependence in the pre-deformation. This anisotropic behaviour was investigated in detail. Results showed that shear band formation occurred in the adhesive owing to the load during the cooling of joined structures. The restructuring of the polymer structure leads to changes in the mechanical properties. [ABSTRACT FROM AUTHOR]

A simple model to evaluate the effects of relative displacements between the ground anchors of a suspension bridge is proposed. An equation system is defined, which allows for the evaluation of the structural response under a general displacement set of the ground anchor points. Then, the most interesting and likely cases are analyzed in detail with reference to a suspension bridge having geometrical and mechanical characteristics typical of a long-span bridge. A simple procedure for the assessment of variation in cable stress is also given, which can be used to choose the optimum values for stress in cables under dead loads, as a percentage of their strength. The results obtained showed that expected movements do not significantly impact the structure in its lifetime and that the effects become negligible for very long-span bridges. Finally, the results obtained can be easily used for the condition monitoring of suspension bridges. [ABSTRACT FROM AUTHOR]

A simple model to evaluate the effects of relative displacements between the ground anchors of a suspension bridge is proposed. An equation system is defined, which allows for the evaluation of the structural response under a general displacement set of the ground anchor points. Then, the most interesting and likely cases are analyzed in detail with reference to a suspension bridge having geometrical and mechanical characteristics typical of a long-span bridge. A simple procedure for the assessment of variation in cable stress is also given, which can be used to choose the optimum values for stress in cables under dead loads, as a percentage of their strength. The results obtained showed that expected movements do not significantly impact the structure in its lifetime and that the effects become negligible for very long-span bridges. Finally, the results obtained can be easily used for the condition monitoring of suspension bridges.

The formation of surface texture in milling is a complex process affected by numerous factors. This paper focuses on the surface roughness of X37CrMoV51 steel machined by shoulder milling. The aim of the study was to develop a mathematical model to predict the surface roughness parameter Ra. The proposed model for predicting the surface roughness parameter Ra in shoulder milling takes into account the feed per tooth, fz, the corner radius, rε, and the actual number of inserts involved in the material removal process as well as hmin and D(ξ). The correlation coefficient between the theoretical and experimental data was high (0.96). The milling tests were carried out on a three-axis vertical milling machine using a square shoulder face mill. The geometric analysis of the face mill shows that at a feed rate of 0.04 mm/tooth, cutting was performed by three out of five inserts, and when the feed rate exceeded 0.12 mm/tooth, material was removed by all inserts. The minimum chip thickness parameter and the standard deviation of the relative displacement increased as the feed increased. Over the whole range of feeds per tooth, the displacement increased by 0.63 µm. Higher cutting speeds resulted in lower minimum chip thicknesses and the average standard deviation of the relative displacements for the whole range of cutting speeds was 2 μm. [ABSTRACT FROM AUTHOR]

In this paper, a two-level multi-group approach to seismic performance assessment of existing building stock is presented and discussed. The first level of assessment is a simple visual screening based on the principles originally developed in FEMA (Rapid visual screening of buildings for potential seismic hazards: a handbook—FEMA 154 and 155, Applied Technology Council, Redwood City, 2002). The second level of assessment is based on an integrated approach (field survey, geotechnical investigations, experimental testing and analytical investigations) with incorporated procedures of different levels of complexity. The acceptance criteria for assessment are founded on demand versus capacity relationships, defined at element and story level. The developed approach was applied in performance assessment of the existing buildings in Karposh, which is one of the largest and oldest municipalities in Skopje, the capital of the Republic of Macedonia. Rapid visual screening (level_1 activity) was performed for 161 existing buildings. For two selected buildings, level_2 assessment was carried out. The results from the assessment were uploaded into the existing geo-referenced building inventory database on the Karposh municipality that represents a practical tool for the decision makers in enforcing decisions on design and construction of seismically resilient building environment. [ABSTRACT FROM AUTHOR]

Abstract: The ongoing experimental campaigns of RFX-mod are performed setting operational parameters at the nominal or exceeding design values of the experiment. Compressive forces up to 11MN are produced by high magnetizing currents that reach values up to 50kA. These forces heavily load the mechanical structure of RFX-mod and their effects are measured and monitored in order to assess the expected structural response and machine reliability during operation. Mechanical strains and relative displacements are real time measured during each experimental pulse by 48 strain gauges located on 12 mechanical struts and 16 potentiometers positioned between the toroidal assembly and the support mechanical structure. The strains in the most stressed components are measured by means of 24 half bridge gauges preliminarily calibrated. Particular care has been given to sensor choices and installation in order to minimize signal noises induced by the electrical and magnetic fields. The residual noises have been further reduced by proper sampling frequency and averaging techniques. The strains measured on the struts are then post-processed to calculate the resultant forces and bending moments, while the displacement measurements give an estimate of the overall stiffness of the mechanical structure. The measured forces and displacements are shown per toroidal locations and as a function of the current intensity, so verifying the uniform sharing of forces among the different struts and the proper square law correlation with the magnetizing current intensity. [ABSTRACT FROM AUTHOR]

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines. [ABSTRACT FROM AUTHOR]