http://www.k-wave.org/forum/topic/failed-to-record-shear-stress Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 22:25:21 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-7007 Thu, 22 Aug 2019 15:44:23 +0000 Bradley Treeby 7007@http://www.k-wave.org/forum/ <p>Hi Patrick,</p> <p>Unfortunately, it is still not in the current release. Yes, that looks correct.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6995 Sun, 04 Aug 2019 05:25:55 +0000 Patrick 6995@http://www.k-wave.org/forum/ <p>As a follow-up. I modified the 3D elastic code to record the normal components of shear stress. Am I correct in using <code>sxx = sxx_split_x + sxx_split_y + sxx_split_z</code>? (and similarly for syy and szz and of course with the correct indexing)</p> <p>Thanks again,<br /> PC </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6994 Sun, 04 Aug 2019 04:25:24 +0000 Patrick 6994@http://www.k-wave.org/forum/ <p>Hello,</p> <p>Has the ability to record the components of shear stress been implemented in the current release? If so, how can this be done?</p> <p>Thanks,<br /> PC </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6802 Wed, 27 Mar 2019 15:48:28 +0000 svch1mail 6802@http://www.k-wave.org/forum/ <p>Hi,<br /> I had the same problem.<br /> Thank you Brad for explanations, they work, but additionally in pstdElastic2D.m it need to add after 1017 line someting like:<br /> SS.p=sensor_data.p;<br /> SS.sxy=sensor_data.sxy;<br /> sensor_data = SS;%sensor_data.p;<br /> Thanks,<br /> Sergiy </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6396 Sun, 08 Apr 2018 18:44:39 +0000 Bradley Treeby 6396@http://www.k-wave.org/forum/ <p>Hi Andy,</p> <p>For k-Wave V1.2, to hack it into the <code>pstdElastic2D</code> in the simplest way, immediately before the time loop (line 617) add:</p> <p><code>sensor_data.sxy = castZeros([num_sensor_points, num_recorded_time_points]);</code></p> <p>Then after line 814, add the following:</p> <p><code>sensor_data.sxy(:, file_index) = sxy_split_x(sensor_mask_index) + sxy_split_y(sensor_mask_index);</code></p> <p>Similarly for 3D. Note, I haven't tried this, so let me know if it doesn't work for some reason.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6374 Mon, 26 Mar 2018 18:24:04 +0000 ad000000 6374@http://www.k-wave.org/forum/ <p>Hi Brad,<br /> Could you give a little bit more advice on the above hack? I'm modeling the typical NDT case of a longitudinal wave launched in an acrylic wedge, which gets converted to shear wave in a steel part. I'd like to extract the pressure (or velocity) from the shear wave in the steel, but there is also a longitudinal wave there (a couple, actually). So the "u" or "u_max" data would map both waves together. The shear stress, if it could be extracted and saved, would solve that problem.<br /> Thanks,<br /> Andy </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6212 Fri, 10 Nov 2017 15:22:49 +0000 Bradley Treeby 6212@http://www.k-wave.org/forum/ <p>Hi Lenny,</p> <p>You can define which parameters you would like to record using the <code>sensor.record</code> input (see the documentation for details). Unfortunately, it's not currently possible to record the components of the stress (only the particle velocity or pressure). If you're comfortable with MATLAB, it is pretty easy to hack into the code (add it after line 814 in V1.2). It's on the list for a future release.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6202 Wed, 08 Nov 2017 19:34:43 +0000 xzy9588 6202@http://www.k-wave.org/forum/ <p>This is my code</p> <p>clear all<br /> close all<br /> % create the computational grid<br /> Nx = 100; % number of grid points in the x (row) direction<br /> Ny = 200; % number of grid points in the y (column) direction<br /> dx = 0.1e-3; % grid point spacing in the x direction [m]<br /> dy = 0.1e-3; % grid point spacing in the y direction [m]<br /> kgrid = kWaveGrid(Nx, dx, Ny, dy);</p> <p>% define the properties of the upper layer of the propagation medium<br /> medium.sound_speed_compression = 1500 * ones(Nx, Ny); % [m/s]<br /> medium.sound_speed_shear = zeros(Nx, Ny); % [m/s]<br /> medium.density = 1000 * ones(Nx, Ny); % [kg/m^3]</p> <p>% define the properties of the lower layer of the propagation medium<br /> medium.sound_speed_compression(Nx/2:end, :) = 2000; % [m/s]<br /> medium.sound_speed_shear(Nx/2:end, :) = 800; % [m/s]<br /> medium.density(Nx/2:end, :) = 1200; % [kg/m^3]</p> <p>% create the time array<br /> cfl = 0.05; % Courant-Friedrichs-Lewy number<br /> t_end = 5e-6; % [s]<br /> kgrid.makeTime(max(medium.sound_speed_compression(:)), cfl, t_end);</p> <p>% define a source</p> <p>source.s_mask = makeLine(Nx, Ny, [Nx/2,1],[1,Ny/2]);<br /> %source.u_mask = makeLine(Nx, Ny, [Nx/2,1],[1,Ny/2]);<br /> %create initial pressure distribution using makeDisc<br /> disc_magnitude = 400; % [Pa]<br /> source.p0 = disc_magnitude*source.s_mask ;<br /> % define a time varying source<br /> %source_freq = 1e6; % [Hz]<br /> %source_mag = 0.00002;<br /> %source.ux = source_mag * sin(2 * pi * source_freq * kgrid.t_array);<br /> %source.uy = source_mag * sin(2 * pi * source_freq * kgrid.t_array);</p> <p>%display_mask=source.u_mask;<br /> sensor.mask=makeLine(Nx,Ny,[40,40],[60,60]);<br /> % define input arguments<br /> input_args = {'PlotScale', [-100, 100, -70, 70], 'PlotPML', false,...<br /> 'DisplayMask', sensor.mask, 'DataCast', 'single'};</p> <p>% run the simulation<br /> sensor_data = pstdElastic2D(kgrid, medium, source, sensor, input_args{:});</p> <p>imagesc(sensor_data);<br /> colormap(getColorMap);<br /> colorbar; </p> http://www.k-wave.org/forum/topic/failed-to-record-shear-stress#post-6201 Wed, 08 Nov 2017 18:56:19 +0000 xzy9588 6201@http://www.k-wave.org/forum/ <p>Hello everyone,</p> <p>I tried to record the magnitude of shear stress using linear sensor mask to see how longitudinal wave can generate shear wave in a layered medium. But we failed to record the shear stress in sensors. How can I record the magnitude of shear stress as well as the pressure of longitudinal wave? </p> <p>Thank you<br /> Lenny </p>