# SPIF formula interpretation assistance

1. Nov 6, 2015

### ophiuci

Hello, I'm trying to apply formula 30 as described on page 12 of this paper:
https://lirias.kuleuven.be/bitstream/123456789/261102/1/IJAMT_journal_final.pdf

However, the results I am getting when testing against the table of results on that same page for Al 2024 (Rm = 435 N/mm2) are off in my javascript interpretation:
Code (Text):

<script>
return angle * (Math.PI / 180);
}
function c(t, dt, a, dh, measured, computed, error) {
var Rm = 435; // tensile strength of aluminum 2024
var Fz_s = 0.0716 * Rm * Math.pow(t,1.57) * Math.pow(dt,0.41) * Math.pow(dh,0.09) * a * Math.cos(toRadians(a));
console.log(Fz_s + ":" + computed)
}

c(0.4, 10, 20, 0.005, 177.7, 192.9, 8.6);
c(0.4, 10, 20, 0.015, 197.3, 213.0, 7.9);
c(0.4, 10, 35, 0.005, 333.4, 320.6, -3.8);
c(0.4, 10, 35, 0.015, 368.7, 354.0, -4.0);
c(0.4, 20, 20, 0.005, 300.9, 256.4, -14.8);
c(0.4, 20, 20, 0.015, 341.5, 283.0, -17.1);
c(0.4, 20, 35, 0.005, 581.8, 426.0, -26.8);
c(0.4, 20, 35, 0.015, 618.7, 470.3, -24.0);
c(1.0, 10, 20, 0.005, 767.6, 813.2, 5.9);
c(1.0, 10, 20, 0.015, 822.0, 897.7, 9.2);
c(1.0, 10, 35, 0.005, 1244.6, 1351.4, 8.6);
c(1.0, 10, 35, 0.015, 1418.0, 1491.9, 5.2);
c(1.0, 20, 20, 0.005, 1092.5, 1080.5, -1.1);
c(1.0, 20, 20, 0.015, 1229.6, 1192.8, -3.0);
c(1.0, 20, 35, 0.005, 1825.2, 1795.6, -1.6);
c(1.0, 20, 35, 0.015, 2056.5, 1982.2, -3.6);
</script>

Any help would be appreciated. Thanks.

2. Nov 11, 2015

### Greg Bernhardt

Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?