Physiological Effects of A Mechanical Counter Pressure Glove

Materials and Textile Architecture Analyses for Mechanical Counter-Pressure Space Suits using Active Materials

“…1a), but the concept was tabled due to limitations in available materials, user discomfort, funding, and donning and doffing challenges 6 . More recent research efforts to advance MCP suit design have been conducted at multiple universities, including at the University of San Diego and in the Man Vehicle Laboratory (MVL) at MIT 5,[7][8][18][19][20][21][22][23][24][25][26] . The MIT BioSuit™ system (see Fig.…”

Modeling and Testing of a Mechanical Counterpressure Bio-Suit System

“…This group subsequently developed a full elastic sleeve for the arm that produced a higher pressure of 31 kPa at the finger, dorsum, and wrist, but only 21 kPa at the forearm and upper arm. Despite this wide pressure range, again the sleeve prevented adverse changes for underpressures of up to -20 kPa for 5 minutes [8,9,10].…”

“…function [h,r,strain,w,f,mark,wcircum]=band_determine (zcoord,circum,x,y,knee,max) %This function actually does the calculations to produce the calibratied %bands %The following 2 lines need to be changed if a single wrap or double wrap %or triple wrap is being used pressure_perlayer=15; %7.5 kPa is 2 double wraps (ie the cut and paste for the dummies) %15 is a normal double wrap %30 is a single wrap %10 is a triple wrap width_factor=1/2; %1/3 for triple wrap %1/2 for double wrap %for single wrap change this to 5 mm, and remove the necessary code as %shown below, noted by the ****** h(1)=40; % start 40 mm above ankle r(1)=circum(2)/2/pi; % start at 4 cm above the ankle to calculate the radius based on the % circumference mark(1,1:7)=0; mark (1,8)=circum(2)/10; %Note this outputs in cm % the first part of the wrap is to go over the leg, and then the second % layer is actually used to create the pressure w(1)=0;%want to wrap over immediately f(1)=0; n=2; %start with the 2nd mark, which is 4 cm above the ankle while h(n-1)< max h(n)=h(n-1)+width_factor*w(n-1); %****** %h(n)=h(n-1_+width_factor; %this is only for single wrap for m=1:length(circum)-1 %loops through to find the right circumference to use if h(n)<zcoord(m) break end end ratio=(circum(m)-circum(m-1))/(zcoord(m)-zcoord(m-1)); wcircum(n)=ratio*(h(n)-zcoord(m))+circum(m); %calculates circumference of actual cross-section using interpolation r(n)=wcircum(n)/2/pi; %radius of actual cross-section FperW(n)=pressure_perlayer*r(n)/1000; %make sure in N/mm as above %15 kPa indicates double wrap, 30 kPa indicates single, 7.5 kPa %indicates two double wraps, etc. strain(n)=x(1)*FperW(n)^3+x(2)*FperW(n)^2+x(3)*FperW(n); %calculates strain using FperW w(n)=y(1)*FperW(n)^2+y(2)*FperW(n)+y(3); %material width f(n)=FperW(n)*w(n); %actual force to be used on the material %outputs to check if this is reasonable for the investigator n=n+1; end prev_mark=mark (1,8) [h,r,strain,w,f,mark,wcircum]=thigh_down_wrap (zcoord,circum,x,y,knee,max) %This function actually does the calculations to produce the calibratied %bands %The following 2 lines need to be changed if a single wrap or double wrap %or triple wrap is being used pressure_perlayer=15; %7.5 kPa is 2 double wraps (ie the cut and paste for the dummies) %15 is a normal double wrap %30 is a single wrap %10 is a triple wrap width_factor=1/2; %1/3 for triple wrap %1/2 for double wrap %for single wrap change this to 5 mm, and remove the necessary code as %shown below, noted by the ****** h(1)=40; % start 40 mm above ankle r(1)=circum(2)/2/pi; % start at 4 cm above the ankle to calculate the radius based on the % circumference mark(1,1:7)=0; mark (1,8)=circum(2)/10; %Note this outputs in cm % the first part of the wrap is to go over the leg, and then the second % layer is actually used to create the pressure w(1)=0;%want to wrap over immediately f(1)=0; n=2; while h(n-1)>40 % set at 40 to ensure we use circum (1) which is at 20 mm, and the width of the material is slightly less than 20 mm too h(n)=h(n-1)-width_factor*w(n-1); %here we are wrapping down ****** %h(n)=h(n-1)-width_factor; for m=1:length(circum)-1 %loops through to find the right circumference to use if h(n)>zcoord(m) break end end %m ratio=(circum(m)-circum(m-1))/(zcoord(m)-zcoord(m-1)); wcircum(n)=ratio*...…”

“…strain(n)=x(1)*FperW(n)^3+x(2)*FperW(n)^2+x(3)*FperW(n); %calculates strain using FperW w(n)=y(1)*FperW(n)^2+y(2)*FperW(n)+y(3); %material width f(n)=FperW(n)*w(n); %actual force to be used on the material %outputs to check if this is reasonable for the investigator n=n+1; end prev_mark=mark (1,8) [h,r,strain,w,f,mark,wcircum]=thigh_down_wrap (zcoord,circum,x,y,knee,max) %This function actually does the calculations to produce the calibratied %bands %The following 2 lines need to be changed if a single wrap or double wrap %or triple wrap is being used pressure_perlayer=15; %7.5 kPa is 2 double wraps (ie the cut and paste for the dummies) %15 is a normal double wrap %30 is a single wrap %10 is a triple wrap width_factor=1/2; %1/3 for triple wrap %1/2 for double wrap %for single wrap change this to 5 mm, and remove the necessary code as %shown below, noted by the ****** h(1)=40; % start 40 mm above ankle r(1)=circum(2)/2/pi; % start at 4 cm above the ankle to calculate the radius based on the % circumference mark(1,1:7)=0; mark (1,8)=circum(2)/10; %Note this outputs in cm % the first part of the wrap is to go over the leg, and then the second % layer is actually used to create the pressure w(1)=0;%want to wrap over immediately f(1)=0; n=2; while h(n-1)>40 % set at 40 to ensure we use circum (1) which is at 20 mm, and the width of the material is slightly less than 20 mm too h(n)=h(n-1)-width_factor*w(n-1); %here we are wrapping down ****** %h(n)=h(n-1)-width_factor; for m=1:length(circum)-1 %loops through to find the right circumference to use if h(n)>zcoord(m) break end end %m ratio=(circum(m)-circum(m-1))/(zcoord(m)-zcoord(m-1)); wcircum(n)=ratio*(h(n)-zcoord(m))+circum(m); %calculates circumference of actual cross-section using interpolation r(n)=wcircum(n)/2/pi; %radius of actual cross-section FperW(n)=pressure_perlayer*r(n)/1000; %make sure in N/mm as above strain(n)=x(1)*FperW(n)^3+x(2)*FperW(n)^2+x(3)*FperW(n); %calculates strain using FperW w(n)=y(1)*FperW(n)^2+y(2)*FperW(n)+y(3); %material width f(n)=FperW(n)*w(n); %actual force to be used on the material %outputs to check if this is reasonable for the investigator n=n+1; end prev_mark=mark (1,8) if sub==1 %subject 8 zcoord=xlsread('leg circumferences','sheet1','a2:a33'); %cm circum=xlsread('leg circumferences','sheet1','h2:h33'); %cm circum_under_pressure=xlsread('leg circumferences','legs under pressure','c2:c28');%cm knee=420; max=620; elseif sub==2 %subject 4 zcoord=xlsread('leg circumferences','sheet1','a2:a33'); %cm circum=xlsread('leg circumferences','sheet1','b2:b33'); %cm circum_under_pressure=xlsread('leg circumferences','subject 4 leg under pressure','c2:c33');%cm knee=420; max=640; elseif sub==3 %subject 1 zcoord=xlsread('leg circumferences','sheet1','a2:a31'); %cm circum=xlsread('leg circumferences','sheet1','c2:c31'); %cm circum_under_pressure=xlsread('leg circumferences','legs under pressure','i2:i31');%cm knee=380; max=580; elseif sub==4 %subject 2 zcoord=xlsread('leg circumferences','sheet1','a2:a38'); %cm circum=xlsread('leg circumferences','sheet1','g2:g38'); %cm knee=460; max=720; elseif sub==5 %unused sub 2 zcoord=xlsread('leg circumferences','sheet1','a2:a35'); %cm circum=xlsread('leg circumferences','sheet1','j2:j35'); %cm knee=420; max=640; elseif sub==6 %subject 3 zcoord=xlsread('leg circumferences','sheet1','a2:a32'); %cm circum=xlsread('leg circumferences','sheet1','i2:i32'); %cm circum_under_pr...…”

“…Therefore, you can't % consider the top or bottom row, since you would have only 5 % surrounding points. dist_init=zeros (8,3); dist_def=zeros (8,3); %temporary placeholder, its for the x,y,z distance from a given point to %its 8 neighbors row=mesh_init(n).row; column=mesh_init(n).column; if (column>1)&(column<columns) %calculates the distance between the marker surrounded by 8 neighbors %start at neighbor at the right and go counterclockwise to other %seven neighbors, for more explanation, see Wolfrum thesis dist_init(1,:)=mesh_init(n+1).coord-mesh_init(n).coord; dist_init(2,:)=mesh_init(n+columns+1).coord-mesh_init(n).coord; dist_init(3,:)=mesh_init(n+columns).coord-mesh_init(n).coord; dist_init(4,:)=mesh_init(n+columns-1).coord-mesh_init(n).coord; dist_init(5,:)=mesh_init(n-1).coord-mesh_init(n).coord; dist_init(6,:)=mesh_init(n-columns-1).coord-mesh_init(n).coord; dist_init (7,:)=mesh_init(n-columns).coord-mesh_init(n).coord; dist_init (8,:)=mesh_init(n-columns+1).coord-mesh_init(n).coord; %does same thing for bent leg dist_def(1,:)=mesh_def(n+1).coord-mesh_def(n).coord; dist_def(2,:)=mesh_def(n+columns+1).coord-mesh_def(n).coord; dist_def(3,:)=mesh_def(n+columns).coord-mesh_def(n).coord; dist_def(4,:)=mesh_def(n+columns-1).coord-mesh_def(n).coord; dist_def(5,:)=mesh_def(n-1).coord-mesh_def(n).coord; dist_def(6,:)=mesh_def(n-columns-1).coord-mesh_def(n).coord; dist_def (7,:)=mesh_def(n-columns).coord-mesh_def(n).coord; dist_def (8,:)=mesh_def(n-columns+1).coord-mesh_def(n).coord; end if column==1 %if the point is in the first column, its three neighbours on the %lefthand side are in last column, so the code has to be changed to %reflect this counting method dist_init(1,:)=mesh_init(n+1).coord-mesh_init(n).coord;% here the markers on the righthand side are in first column, so % again some slight changes must be made to get the appropriate % neighbors dist_init(1,:)=mesh_init(n-columns+1).coord-mesh_init(n).coord; dist_init(2,:)=mesh_init(n+1).coord-mesh_init(n).coord; dist_init(3,:)=mesh_init(n+columns).coord-mesh_init(n).coord; dist_init(4,:)=mesh_init(n+columns-1).coord-mesh_init(n).coord; dist_init(5,:)=mesh_init(n-1).coord-mesh_init(n).coord; dist_init(6,:)=mesh_init(n-columns-1).coord-mesh_init(n).coord; dist_init (7,:)=mesh_init(n-columns).coord-mesh_init(n).coord; dist_init (8,:)=mesh_init(n-2*columns+1).coord-mesh_init(n).coord; dist_def(1,:)=mesh_def(n-(columns-1)).coord-mesh_def(n).coord; dist_def(2,:)=mesh_def(n+1).coord-mesh_def(n).coord; dist_def(3,:)=mesh_def(n+columns).coord-mesh_def(n).coord; dist_def(4,:)=mesh_def(n+columns-1).coord-mesh_def(n).coord; dist_def(5,:)=mesh_def(n-1).coord-mesh_def(n).coord; dist_def(6,:)=mesh_def(n-columns-1).coord-mesh_def(n).coord; dist_def (7,:)=mesh_def(n-columns).coord-mesh_def(n).coord; dist_def (8,:)=mesh_def(n-2*columns+1).coord-mesh_def(n).coord; end %calculating eight normal vectors between pairs of neighboring vectors normals=zeros (8,3); %placeholder for i=1:7, %ORIGINAL CODE, but normal vectors in wrong direction (point inwards)!!!!!!!!!!!!!!!!! %normals(i,:)=cross(dist_init(i,:),dist_init(i+1,:))/norm(cross(dist_init(i,:),dist_...…”