Search results for "INTERFACE"
showing 10 items of 2139 documents
Adhesive inter-laminar and cohesive inner-layer damage mechanisms for composite materials
2009
A Cohesive interface formulation in large displacements
2017
Mechanical interfaces are theoretical and computational tools able to properly reproduce the progressive decohesion along predefined surfaces. Scientific literature is rich of interface models, developed under very different conctitutive framework, but mostly developed in small displacements, whereas a few of them assess the problem in a geometrically nonlinear setting. In the present contribution interface formulation is rigorously developed in the large displacements regime. The relevant cohesive interface constitutive relations are defined in the local reference with normal and tangential axes to the middle surface in the current configuration. The interface is defined as a zero thicknes…
Finite element modeling of the shear behavior of hybrid steel trussed concrete beams
2015
The development and calibration of a three-dimensional (3D) nonlinear Finite Element (FE) model is presented with the aim of investigating the shear behavior of steel-concrete composite beams realized with a steel truss embedded into a concrete core and named Hybrid Steel Trussed-Concrete Beams (HSTCBs). The model is calibrated on the results of a reference experimental campaign of three-point bending tests on HSTCBs realized at the Laboratory of Structures of the University of Palermo. The actual behavior at the steel-concrete interface has been introduced in the model through the implementa-tion of a cohesive constitutive relationship. Furthermore, the damaged plasticity of concrete has b…
Development of a software package with GUI for the evaluation of monolithicity factors of RC jacketed columns
2023
The design of reinforced concrete (RC) jacketing for retrofitting substandard columns is a common practice when approaching the structural rehabilitation design of existing structures. In this framework, international technical codes suggest to assume the hypothesis of monolithic section and finally affecting the deduced performances by some empirical factors, known in the literature as monolithicity factors. The assessment of these coefficients is a difficult task, and only some rough assumptions can be found in the modern codes. This paper presents the development of a software package able to perform the static non-linear analysis of RC jacketed columns and evaluating the actual value of…
An interface model for the analysis of the compressive behaviour of RC columns strengthened by steel jackets
2019
Steel jacketing technique is a retrofitting method often employed for static and seismic strengthening of existing reinforced concrete columns. When no continuity is given to angle chords as they cross the floor, the jacket is considered “indirectly loaded”, which means that the load acting on the column is transferred partially to the external jacket through interface shear stresses. The evaluation of load transfer mechanism between core and jacket is not straightforward to be modeled, due to the absence of knowledge of a proper constitutive law of the concrete-to-steel interface and to the difficulties in taking into account the mechanical nonlinearities of materials. This paper presents …
A numerical study on the effect of the interface material model on the tensile behaviour of FRCM strips
2019
Fibre Reinforced Cementitious Matrix (FRCM) composites are becoming increasingly popular for strengthening masonry structures for which the compatibility of the inorganic matrix with the chemical and physical properties of the support makes it advantageous to adopt such systems. However, despite the large use of FRCMs for strengthening applications, the characterization and modelling of the mechanical response in tension of these systems is an open issue. In fact, the constitutive tensile law of the composite shows to be affected by different variables, such as the clamping system adopted during tensile test, the gauge length used for recording strains, the monitoring of the number of yarns…
Accessing and selecting menu items by in-air touch
2019
Is it possible to realize a non-visual, purely tactile version of an icon-based menu? Driven by such question, a hierarchical tactile dock was designed for an array of ultrasound emitters. The icons were conceived as spatio-temporal variable-speed sequences of tactile stimulation points, that are passively perceived as trajectories drawn on the palm of the hand. The recognition rate on four icons largely improved prior performance results obtained by active haptic exploration. As a result, a four-icons set can be used as the first level of a hierarchy of symbols that can be navigated by touch and gesture. The design process, based on controlled recognition experiments and exploration of dis…
TickTacking – Drawing trajectories with two buttons and rhythm
2023
The navigation of two-dimensional spaces by rhythmic patterns on two buttons is investigated. It is shown how direction and speed of a moving object can be controlled with discrete commands consisting of duplets or triplets of taps, whose rate is proportional to one of two orthogonal velocity components. The imparted commands generate polyrhythms and polytempi that can be used to monitor the object movement. Tacking back and forth must be used to make progress along certain directions, similarly to sailing a boat upwind. The proposed rhythmic navigation technique is tested with a target-following task, using a boat-racing trace as the target. The interface is minimal and symmetric, and can …
Shape analysis for image retrieval
1994
The main aim of this paper is to describe a method for locating a subimage of a stored image that approximately matches a given query image. This matching can support naive users in accessing an image database according to image contents rather symbolic attributes. The query image can be either composed using painting tools or cuts out of an actual scanned image. Our method is based on the extraction of features from the query image and from the stored images. The following three steps are involved: (l) an ISODATA algorithm is applied to segment (into region) both the query image and the stored images; (2) the normalized moment and geometrica! features are computed from the segmented region…