Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 16 of 16 for “"Impact-Echo"”.
-
Advancements in evaluation of air-coupled impact-echo test method
… to investigate a recently-developed air-coupled impact-echo (IE) nondestructive testing (NDT) method, in which microphones replace the traditional physically-coupled IE sensors. To develop an optimum testing system and verify the new method, two concrete plates were tested in the laboratory, one …
-
Robotic Inspection Using Learning Based Impact Echo For Civil Infrastructure
… other methods to maintain structural integrity. Impact echo (IE) is an acoustic non-destructive evaluation (NDE) technique essential for assessing the structural integrity of concrete structures, such as bridge decks. IE data interpretation has traditionally been manual, while automated frequency …
-
Probabilistic impact-echo method for nondestructive detection of defects around steel reinforcing bars in reinforced concrete
… this dissertation assesses and improves the Impact-Echo (IE) method for the detection of defects around steel reinforcing bars in concrete. IE involves deducing the presence of a defect from several single-point recordings of a resonant response that results from a non-damaging impact. IE has …
-
Non-Contact NDT of Concrete Structures Using Air -Coupled Sensors
The second application is air-coupled impact-echo. Two reinforced concrete slabs containing different types of defects were inspected using an air-coupled impact test testing scheme. 2-D scanning impact-echo tests were conducted over the slab containing voids and delaminations. The 2-D scanning …
-
Evaluating The Most Reliable Combination Of Non-Destructive Test Methods For Concrete Uniformity And Relative Compressive Strength.
… hammer method, Ultrasonic pulse velocity and Impact Echo methods before coring and 28 days after coring and repair of the two beams. Destructive testing was also conducted through drilling of cores from the RC beams and laboratory testing for compressive strength, for a comparative analysis …
-
Advances in Nondestructive Testing of Concrete Pavements
… First an alternative interpretation of the Impact-Echo method, based on guided wave theory, is presented. This provides a closer match between theoretical and observed results, and ultimately a more accurate basis for testing. A new, time-domain based method is then proposed to address some …
-
Investigation of the Addition of Basalt Fibres into Cement
… concrete such as ultrasonic pulse velocity and impact echo tests. One of major issues with concrete (which has cement as its prime ingredient) is that unlike steel it is quasi-brittle material. It tends to want to crack when tensile stresses develop. Fibres have been added to concrete for many …
-
Měření akustických vlastností stavebních materiálů pomocí pseudonáhodné sekvence
… analýza, která je porovnávána s metodou impact-echo. Funkčnost a optimalizace metody byla provedena na celkem třech sadách zkušebních vzorků zhotovených z různých stavebních materiálů. Provedené experimenty prokázaly jednoduchou interpretaci použité metody a vysokou citlivost na poruchy …
-
Bond Performance between Corroded Steel and Recycled Aggregate Concrete Incorporating Nano Silica
… as water to binder ratio. The feasibility of the impact-echo method for identifying the corrosion was evaluated and compared to the corrosion obtained by mass loss method. The results showed that the impact-echo testing can be effectively used to qualitatively detect the damage caused by corrosion …
-
Detection and assessment of wood decay – glulam beams and wooden utility poles
… described: ultrasonic through-transmission and impact-echo. The analysis of the wooden utility poles starts with the development of a two-dimensional, finite difference time domain (FDTD) simulation to model wave propagation through the pole. The simulation is validated against empirical …
-
In-situ assessment of concrete bridge decks and pavements using stress-wave based methods
… including ultrasonic surface wave (USW) and impact echo (IE), are becoming popular for characterizing defects and mechanical properties of concrete infrastructures. In this dissertation, a comprehensive literature review of seismic wave theory and common types of defects identified in …
-
Adaptive data analysis for damage detection and system identification in civil infrastructure
… analytical signals, acoustic emission and impact echo responses. M-AMD is a response decomposition method for the identification of weakly to moderately nonlinear oscillators based on vibration responses. It can be used to accurately separate the low and high frequency components of …
-
Sedimentation and Consolidation of cohesive and non-cohesive soils formed under turbulent flows
… weight at settling and consolidation stages. Impact echo technique has never been applied to measure the dry unit weight of self-weight consolidation along the vertical stratification of cohesive and non-cohesive particles. Also, a novel conductance sensor has been developed to improve the …
-
Corrosion performance of coated steel bars in cracked and uncracked reinforced concrete beams
… abrasion resistance, reducing the likelihood of impact-caused coating defects that could expose the underlying carbon steel that would lead to corrosion in road-salt chloride ion environments. Despite several studies investigating the mechanical performance of TEC as compared to ECR, no study has …
-
Modeling and detection of delaminations in laminated plates
… Destructive Evaluation techniques, namely the Impact-echo Method and the Sounding Method. We carry out parametric analyses for how the size and depth of a delamination affect the frequency response of the plate. We draw conclusions as to the limits of these methods in detecting delaminations …
-
Defect characterization in concrete elements using vibration analysis and imaging
… existing concrete structures. The conventional impact-echo (IE) test, which utilizes contact type sensors, is an efficient NDE method that is used to identify and characterize internal defects in concrete structures. However large testing volumes associated with the infrastructure demand many …