| This paper summarizes and introduces the research of cypress,the research of mortise-tenon joint performance and the application of finite element method.According to the relevant national standards,the samples are processed and assembled to form the oblique joints of cypress with double round bar tenons.Taking the mortise center distance,diameter and length as three independent variables,the ultimate flexural strength and ultimate pull-out strength of mortise center distance,diameter and length specimens at different levels were tested,and the collected data were collated and analyzed by ANSYS finite element simulation.The following viewpoints and conclusions are synthesized:(1)The ultimate flexural strength of the oblique joints of cypress wood can be improved by reducing the mortise center distance of the two circular tenons appropriately.The relationship between ultimate flexural strength(P)and mortise center distance(A)of oblique-jointed cypress members can be predicted by P=-19.525A+2332.3 with an accuracy of 97.8%.(2)Arrange the mortise center distance between 28 mm and 32 mm,which can make the oblique joints of cypress obtain better ultimate tensile strength.The relationship between ultimate pull-out strength(P)and mortise center distance(A)of oblique joints of cypress can be expressed by P=-2.4732A~2+145.75A-1445,with an accuracy of 95.75%.(3)When the diameter of the tenons is between 10 mm or 10 mm to 12 mm,the best ultimate flexural strength of the oblique joints of cypress can be obtained.The ultimate bending strength(P)of oblique jointed cypress members can be predicted by the quadratic equation P=-50.312D~2+1076.3D-3011.7 with diameter(D)as independent variable,and the accuracy is97.23%.(4)If the diameter of the two tenons is 8 mm or between 8 mm and 10 mm,the ultimate tensile strength of the oblique joints of cypress will be better.The relationship between ultimate pull-out strength(P)and diameter(D)of oblique-jointed cypress members can be expressed by P=-12.469D~2+229.06D-359.54 with an accuracy of 94.26%.(5)When the length of the tenons is about 50 mm,the optimal ultimate flexural strength of the oblique joints of cypress can be obtained.The ultimate bending strength(P)of oblique jointed cypress members can be predicted by the quadratic equation P=-2.5017H~2+251.95H-4199.4 with the accuracy of 99.83%.(6)When the length of the tenons is about 50 mm,the optimal ultimate tensile strength of the oblique joints of cypress can be obtained.The relationship between ultimate pull-out strength(P)and length(H)of oblique-jointed cypress members can be expressed by P=-0.39H~2+37.303H-118.07 with an accuracy of 96.14%.(7)The relative values of failure strength and displacement are the direct reflection of the failure phenomena of the specimens.The ANSYS software validates the ultimate bending tests of the diameter specimens and the length specimens effectively,and improves the reliability of the original tests. |
