Phosphogypsum (PG) occupies a large amount of land due to its annual production and low utilization rate, at the same time causes serious environmental problems toxic impurities. PG is used for mine backfill, industrial solid waste curing agent PG, which can save filling cost reduce pollution. In this paper, was as raw material, combined with steel slag (SS) ground granulated blast-furnace (GGBS) under action an alkali-activated (NaOH) prepare all-solid phosphogypsum-based backfill material...

Evaluation of the seismic performance masonry-infilled reinforced concrete (RC) frames is challenging because a number damage patterns can be induced by interaction between infill and frame. In this paper, extended finite-element method (XFEM) adopted to model cracking behavior compressive failure in frame members as well masonry units panels, discrete interface element employed simulate mortar joints at frame-to-infill interface. With XFEM, crack propagate an arbitrary manner during...

Masonry infill walls should have sufficient out-of-plane stability to ensure the safety of people and performance safety-relevant components. The behaviour masonry under loading, which is caused by earthquakes due mass inertia wall, crucial overall buildings. A simplified micro non-linear three-dimensional finite-element method for simulating infills loading presented in this paper. Appropriate experimental data from literature are utilised examine capability model. parametric study using...

We describe a new simple technique for the low-frequency ultrasonic thickness measurement of an air-backed soft thin layer attached on hard substrate finite through frequency-shifts resonances by substrate-side insonification. A plane compressive wave impinging normally surface from liquid is studied. Low frequency here means interrogating acoustical less than half `half-wavelength resonance frequency' depending impedance ratio coating to substrate. Equations are derived and solved Newton...

Based on the exact solutions for second-harmonic generations of fundamental longitudinal and transverse waves propagating normally through a thin elastic layer between two solids, approximate representations termed as 'nonlinear spring models' relating stresses displacements both sides interface are rigorously developed by asymptotic expansions wave fields an in limit small thickness to wavelength ratio. The applicability so-called nonlinear models is numerically analyzed comparison with...

The propagation of a longitudinal ultrasonic wave normally incident upon an adhesively bonded structure is studied. consists adherend and adhesive layers with finite thickness. Interfaces between are regarded as distributed springs. Theoretical experimental results show that resonant frequencies the vary sensitively interface stiffness constants thickness, these characteristics inversed by simulation annealing (SA) method. Furthermore, distribution image stiffnesses compared state fracture...

The in-plane seismic performance of framed masonry wall has been studied by many researchers all over the world, whereas structures subject not only load but also outof-plane simultaneously in actual events. This paper utilizes three dimensional nonlinear finite element analysis techniques to investigate eect out-of-plane on inplane behavior reinforced concrete (RC) wall. analytical results indicate that pre-applied loads alter failure mode and reduce strength infilled RC frame. When is...

The main problem among the developing of thickness mode piezoelectric air-coupled ultrasonic transducer is acoustic impedance mismatch between plate and air. To solve this problem, a kind porous composite material introduced as matching layer. parameters measurement methods hollow glass microspheres filled epoxy resin studied in article. On basis, pair with layer manufactured. A transmitting receiving testing system using transducers built, uplifting signal voltage peak-to-peak value...

A new expression of the dispersion equation Lamb wave in an adhesive two-layered plate is presented. The bond rigidity accounted for terms a spring model. influence variations compliance constants on feature modes numerically studied. numerical results indicate that deterioration may cause phase velocity decrease and frequency-shift given mode, thus having possibility evaluation bonding state by using ultrasonic measurements. phase-tracing method used to measure velocities experimentally...

We present an ultrasonic method for determining the thickness of a composite consisting soft thin film attached to hard plate substrate, by resonance spectra in low frequency region. The interrogating waves can be incident only two-layered from substrate side. reflection are obtained FFT analysis compressive pulsed echoes composite, and thicknesses simultaneously inversed simulated annealing resonant frequencies knowing other acoustical parameters prior. sensitivity individual thickness, its...

This paper investigates the dynamic contact response of a viscoelastic coated half-plane under forced rigid punch. punch, acting on coating surface, is subjected to concentrated vertical harmonic force. The and are assumed as materials which can be described by linear hysteretic damping model. Using Fourier integral transform technique asymptotic method, problem reduced Cauchy singular equation. By using appropriate numerical stress impedance for flat punch calculated. It found that...

There are a large number of connection interfaces between engine components. The fault acoustic emission (AE) signals collected by the sensors inevitably transmitted through interface. Therefore, it is necessary to study effect interface on AE signal propagation initial damage. This paper presents some simulations with different morphologies finite element method. Their degree influence also investigated using waveform analysis and time-frequency analysis. simulation results verified...

We investigate the relationship between natural frequencies of a multilayered system different elastic materials and thickness undermost thin film. The are numerically calculated from reflection coefficient sample "steel-epoxy resin-aluminium-thin polymer" with normal incidence. Strain energy ratio is defined to give physics explanation why some sensitive film in certain range. Experiments three specimens indicate that measured agree well theoretical ones. It found our experiments lowest...

The non-collinear mixing method for detection of plastic zone at crack tip is studied in this paper. When stress loaded on solid more than critical stress, which related to length crack, the will happen expend fast leading material fracture. However, affected by existence tip, so significant. By method, a nonlinearity parameter utilized evaluate tip. This paper demonstrates feasibility measuring range