The Location of Building Defects Using Structural Intensity

1996 ◽  
Vol 3 (4) ◽  
pp. 217-231
Author(s):  
Robert J.M. Craik ◽  
R. Wilson ◽  
R. Ming
Keyword(s):  
Point Source ◽  
Line Source ◽  
Power Flow ◽  
Concrete Block ◽  
Background Intensity ◽  
Concrete Floor ◽  
Structural Intensity ◽  
Residual Intensity ◽  
Block Wall

Many defects in the construction of buildings act as transmission paths across which unwanted sound can travel. The resulting increase in power flow can be measured using structural intensity techniques and the location of the source found from the intersection of two or more intensity vectors. This technique can be used to locate a source (or sometimes a sink) when the intensity being measured is above the residual or background intensity. Some applications of this technique are discussed and it is used to locate a point source on a concrete floor and a line source exciting a concrete block wall. The technique was found to work well for a point source but was less reliable for a line source. This was partly because a line source is less well spatially defined and partly because the damping of the wall was low, resulting in a high residual intensity.

Structure-Borne Power Transmission in Thin Naturally Orthotropic Plates: General Case

2003 ◽  
Vol 9 (10) ◽  
pp. 1189-1199 ◽  
Author(s):  
Nirmal Kumar Mandal ◽  
Roslan Abd. Rahman ◽  
M. Salman Leong
Keyword(s):  
Fourier Transform ◽  
Power Flow ◽  
Power Transmission ◽  
Far Field ◽  
Orthotropic Plates ◽  
Flow Estimation ◽  
Structural Intensity ◽  
Vibration Power Flow ◽  
Conventional Idea ◽  
Bending Wave

The structural intensity technique is usually used to estimate vibration power flow in structures. This method is used to determine vibration power flow in thin naturally orthotropic plates. The bending wave is considered to find general vibration power transmission in the frequency domain that is not approximated by far field conditions. This intensity formulation defines power flow per unit width of the plates (W m−1) similar to that of the conventional idea. Power flow estimation is formulated using cross-spectra of field signals, facilitating the use of a fast Fourier transform analyzer.

scholarly journals Development and Performance Test including Mechanical and Thermal of New Tenon Composite Block Masonry Walls

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hui Su ◽  
Dongyue Wu ◽  
Mengying Shen ◽  
Wei Chen ◽  
Shilin Wang
Keyword(s):  
Thermal Performance ◽  
Performance Test ◽  
Concrete Block ◽  
Masonry Walls ◽  
Design Code ◽  
Concrete Material ◽  
Mixing Ratios ◽  
Block Wall ◽  
Common Block ◽  
And Performance

To improve the thermal performance of external masonry walls, a new tenon composite block is proposed as the external maintenance component which contains the internal hollow concrete block part, the external block part, and the extruded polystyrene layer fixed by tenons. The production process and concrete material mixing ratio were optimized for the new tenon composite block to promote its application. The mechanical strength and thermal properties of the optimized tenon composite blocks were tested with experiments and numerical simulation in this study. The testing and simulation results indicated that after utilizing the two optimized concrete mixing ratios, the tenon composite block strength matched the strength requirements according to the related design code. The thermal performance of the tenon composite block wall was also good compared with that of a common block wall.

Determination of Dynamic Dispersion Coefficient for Solid Particles Flowing in a Fracture With Consideration of Gravity Effect

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Yanan Ding ◽  
Xiaoyan Meng ◽  
Daoyong Yang
Keyword(s):  
Particle Size ◽  
Point Source ◽  
Line Source ◽  
Dispersion Coefficient ◽  
Solid Particles ◽  
Gravity Effect ◽  
Dispersion Coefficients ◽  
Source Condition ◽  
Advection Diffusion Equation ◽  
Gravity Settling

Abstract A robust and pragmatic method has been developed and validated to analytically determine dynamic dispersion coefficients for particles flowing in a parallel-plate fracture, in which gravity settling has been considered due to its significant impact on particle flowing behavior. More specifically, a two-dimensional (2D) advection–diffusion equation together with the initial and boundary conditions has been formulated to describe the flow behavior of finite-sized particles on the basis of coupling the Poiseuille flow with vertical settling. Meanwhile, three types of instantaneous source conditions (i.e., point source, uniform line source, and volumetric line source) have been considered. Explicit expressions, which can directly and time-efficiently calculate dynamic dispersion coefficient, have been derived through the moment analysis and the Green’s function method. By performing the simulation based on the random walk particle tracking (RWPT) algorithm, the newly developed model has been verified to determine particle dispersion coefficients agreeing well with those obtained from the RWPT simulations. It is found that the point source is the most sensitive to gravity effect among different source conditions, while the volumetric line source is affected more than the uniform line source. For particle size larger than its critical value, an increased particle size leads to a decreased asymptotical dispersion coefficient for all the source conditions due to the significant gravity effect, while gravity positively affects the dispersion coefficient at early times for the point source condition. In addition, average flow velocity positively affects the dispersion coefficient for all the source conditions, while the associated gravity effect is influenced only at early times for the point source condition.

Experimental Study on Compressive Property of New Concrete Block Masonry with Multi-Row Cores

2014 ◽  
Vol 501-504 ◽  
pp. 461-465
Author(s):  
Zhao Yan Cui ◽  
Fu Sheng Liu ◽  
Shun Ke Zhang
Keyword(s):  
Energy Saving ◽  
Diffusion Mechanism ◽  
Concrete Block ◽  
Compressive Property ◽  
Insulation Material ◽  
Test Results ◽  
Failure Characteristics ◽  
New Energy ◽  
Heat Insulation Material ◽  
Block Wall

With the development of energy-saving in buildings, new energy-saving block masonry with multi-row cores is commonly used. In this paper, from the study of typical bearing capacity of multi hole concrete block masonry of combining multiple rows of holes, holes in the multi block wall masonry capacity test of heat insulation material characteristics. Test results show that, in the process of multi hole masonry brittle failure characteristics, built-in straw block in the insulation at the same time, can improve the compressive strength of masonry; masonry local diffusion mechanism under the action of stress is significant; and offer the engineering measures.

Optimized Model of Slotted Liners Completion Parameters in Horizontal Well

2012 ◽  
Vol 616-618 ◽  
pp. 804-811
Author(s):  
Quan Tang Fang ◽  
Wei Chen ◽  
Rong Wang
Keyword(s):  
Point Source ◽  
Line Source ◽  
Flow Resistance ◽  
Horizontal Well ◽  
Source Function ◽  
Geometric Model ◽  
Superposition Principle ◽  
Evaluation Index ◽  
Flow Convergence ◽  
Optimized Model

The transient flowing model of slotted liner completion was established by superposition principle based on the geometric model of slotted liners, with the point source function and the single slotting equal to line source, and then the optimized model of slotted liner completion parameter was established with the skin factor of slotted liners completion as evaluation index. After analyzing the parameter sensitivity with cases, the slot density is confirmed as the main reason leading to flow convergence and additional flow resistance. Furthermore, the optimization principles of slotted liners completion of horizontal well are determined. These results are significant in optimizing the slot distribution pattern and parameter allocation.

Seismic Retrofit of Concrete Block Wall Intersections Using Composite Laminates

2009 ◽  
Vol 29 (11) ◽  
pp. 1609-1625
Author(s):  
Wael W. El-Dakhakhni ◽  
Steve George ◽  
Marwan T. Shedid
Keyword(s):  
Composite Laminates ◽  
Concrete Block ◽  
Seismic Retrofit ◽  
Block Wall

Transformation from 2-D to 3-D wave propagation for horizontally layered media

Geophysics ◽  
1994 ◽  
Vol 59 (12) ◽  
pp. 1920-1926 ◽  
Author(s):  
Lasse Amundsen ◽  
Arne Reitan
Keyword(s):  
Wave Propagation ◽  
Point Source ◽  
Line Source ◽  
Layered Media ◽  
Cylindrical Symmetry ◽  
Seismic Processing ◽  
Geometric Spreading ◽  
Processing Algorithms ◽  
The Relationship ◽  
D Wave

The relationship between 2-D and 3-D wave propagation in horizontally layered media was first investigated by Dampney (1971). In the last few years the usefulness and feasibility of transforming point‐source responses with 3-D geometric spreading to equivalent line‐source responses with 2-D geometric spreading have been thoroughly discussed (see Helgesen, 1990; Wapenaar et al., 1990, 1992; Herrmann, 1992; Helgesen and Kolb, 1993; Amundsen, 1993). In the case of cylindrical symmetry this transformation constitutes a required preprocessing step for several seismic processing algorithms based on 2-D wave propagation. The work of Dampney (1971) has apparently been missed by the authors discussing the 3-D to 2-D geometric spreading transform.

Mechanical Modal and Numerical Simulation of Fracture Process of Block Wall

2011 ◽  
Vol 217-218 ◽  
pp. 1438-1443
Author(s):  
Yan Li ◽  
Xin Sheng Yin ◽  
Bo Wang
Keyword(s):  
Numerical Simulation ◽  
Fracture Toughness ◽  
Fracture Process ◽  
Concrete Block ◽  
Critical Value ◽  
Specimen Size ◽  
Linear Elastic ◽  
Block Wall ◽  
Elastic Fracture ◽  
Aerated Concrete

Aerated concrete is a typical non-uniform quasi-brittle materials, the fracture process is very complicated. To slove the problem of cracks in this block walls, a practical analytical method was proposed based on the vertical mortar joint model to solve the equivalent fracture toughness (the critical value which the crack occurred to spread unstable) With the use of the basic principle of composite material mechanics and linear elastic fracture mechanics. Against the results of the related experiments, the standard deviation and the coefficient of variation of Analytical Solution are smaller, , and the equivalent fracture toughness is the effective fracture parameters of independent of specimen size. So the suggested method is more feasible and applicable, which can forecast autoclaved aerated concrete block wall’s cracking and destroying.

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