Wyniki wyszukiwania - BazTech

1

Badania zmian sztywności belki zespolonej drewniano-betonowej

Czabak M., Perkowski Z., Gozarska K., Jędraszak B.

Inżynieria i Budownictwo

|

2016

|

R. 72, nr 11

604--608

PL

Przedstawiono wyniki analizy badań eksperymentalnych statycznych, dynamicznych i ultradźwiękowych. Na podstawie uzyskanych wyników badań wyznaczono postęp degradacji podstawowych parametrów określających globalną sztywność belki pod cyklicznym i zwiększającym się obciążeniem statycznym, aż do osiągnięcia stanu granicznego nośności.

EN

The results of analysis of experimental tests static, dynamic and ultrasonic for composite wood-concrete beam in a natural scale are presented in the paper. On the basis of obtained results a progress of basic parameters determining the degradation stiffness of beam was determined under cyclic and increasing static load, until the ultimate limit state was reached.

2

Ultradźwiękowe obrazowanie uszkodzeń struktury betonu na przykładzie prefabrykowanej belki żelbetowej

Gozarska K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

|

2015

|

z. 105

69-72

EN

The paper presents possibilities offered within a framework of ultrasonic transmission tomography in reconstructions of sonic wave velocity distribution in the cross-sections of structural concrete members affected by brittle macro- and microdamage. The exemplary reconstruction was performed on the precast reinforced concrete beam which was damaged in a unintentional way during the transport to the building site.

3

Lokalizacja makrorys w belkach żelbetowych na podstawie pomiaru prędkości fali

Gozarska K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

|

2014

|

z. 104

61-64

EN

The paper presents bases of own method for an estimation and localization of cracked areas in bar reinforced concrete elements. The elements of graph theory are used to simplified time-effective modeling propagation of acoustic wave in a material medium. To find the minimum of error function for the measured and determined time-of-flights of ultrasonic waves one employed two methods: genetic algorithms and direct search method.

4

Identyfikacja kruchych mikrouszkodzeń elementów betonowych za pomocą tomografii ultradźwiękowej

Perkowski Z., Gozarska K.

Roczniki Inżynierii Budowlanej

|

2014

|

z. 14

57--62

EN

An application of ultrasonic transmission tomography to reconstructions of ultrasonic wave velocity distribution in cross-sections of structural members affected by brittle microdmageis presented in the paper. To simplify the problem the methods of continuous damage mechanics for modeling change of sonic wave velocity caused by damage of material is employed in the isotropic case. Also the concept of division of tomographically tested cross-sections into square “cells” of constant sound velocities and assuming straight “rays” of ultrasound propagation between the sending-receiving points are introduced in the considerations. Finally own numerical example is discussed for concrete prismatic element which shows a satisfactory precision of the used tomographic imaging if a local drop of sound velocity is not bigger than 20% in a comparis on with material in the undamaged state. The effect is related to neglecting in the considerations the diffraction of ultrasonic waves on the damage areas.

5

Analiza numeryczna propagacji fal ultradźwiękowych w prostokątnych przekrojach prętów

Gozarska K.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

|

2013

|

z. 102

53-56

EN

The paper shows possibilities of numerical simulation in modeling ultrasonic wave propagation in rectangular cross-sections of bars. The presented exemplary numerical simulations were carried out thanks to own program written in the Matlab environment based on Finite Difference Method which the viscoelastic Kelvin-Voigt model for material was assumed in.

6

Szacowanie czasu propagacji fal dźwiękowych w ośrodkach materialnych za pomocą metody Dijkstry

Perkowski Z., Gozarska K.

Roczniki Inżynierii Budowlanej

|

2012

|

z. 12

43--48

EN

A proposition of method enabling an estimation of wave propagation time from point to point (but without refection) in material media is presented in the work. The calculating procedure is based on Fermat’s principle and Dijkstra’s algorithm and it is relatively quick and easy for its implementation by means of individual computer code. It can be used effectively in optimization methods oriented on reconstruction of damage state in engineering structures basing on time-of-flight measurements for mechanical waves.