UA24755U - Method for determining the impact strength of the adhesive bond of the layers of laminated wood - Google Patents

Abstract

The proposed method for determining the impact strength of the adhesive bond of the layers of laminated wood consists in producing slots along the adhesive bond, which are arranged in the middle and along the edges of the material sample, and fixing the sample at the pendulum element of the impact-testing machine so that the edges of the sample are against the rests when the pendulum element moves. The proposed method provides the disintegration of the sample along the adhesive bond in testing the sample.

Description

Description of the invention

The useful model refers to mechanical tests and, in particular, can be used for dynamic 2 quality control of adhesion of layers of plywood, wood plastics, carpentry boards, etc.

There is a known method of determining the impact strength of glued joints made of solid wood made along the fibers using samples in the form of a rectangular prism with dimensions b x x h! equal to 40x30x4 Ohm. (Utility model patent Mo19523, 501 Mo33/46. Byul. Mo12, 12/15/2006, Kotrechka O.O.

The disadvantage of this method is that the significant difference in the size of the thickness of the slats of the glued joints of solid wood compared to the thickness of the layers in plywood, wood plastics, carpentry boards does not allow the use of analogue samples.

A useful model is the task of developing a structure of a sample of laminated wood, which will ensure testing of the strength of glued joints for impact toughness.

The task set by the useful model is achieved by the fact that in the method of determining the impact strength 79 of a glued joint of laminated wood, which includes applying an impact load to the sample, according to the useful model, cuts are made in the sample along the glued joint, one of them with a hole in the middle for fixing it on the back side of the load of the copra pendulum and two - at the ends, which ensure the interaction of the cuts with the copra supports during the application of a shock load, as a result of which the destruction of the sample occurs along the glued connection by tearing off the layers of wood.

Figure 1 shows the design of the sample; Fig. 2 is a diagram of the installation of the sample on the load of the copra pendulum.

In sample 1, one cut 2 with a hole 4 in the middle part is made for the glued connection to attach it to the load 7 of the copra pendulum and two cuts C at the ends, to which the shock load is applied.

An example of the implementation of the method. Sample 1 is fixed with a bolt 5 with a washer b on the back side of the load 7 of the copra pendulum. During the movement of the load 7 of the pendulum at the moment of contact of the saws from sample 1 with the supports 8 of copra 725, the glued joint of wood is subjected to an impact load. 8

The value of the impact strength of the glued joint of laminated wood is determined by the formula:

Adm - C/25.1, J/cm? where O is the work spent on destroying the glued joint of the sample, J; yu

B and I are, respectively, the working width and length of the glued joint of the sample, see

IF)

Claims (1)

The formula of the invention is "A method of determining the impact strength of a glued joint of laminated wood, which includes applying an impact load sample to the sample, which differs in that the sample is cut along the glued joint, one of them with a hole in the middle for securing it on the back side of the load of the copra pendulum and two - at the ends, which ensure the interaction of the cuts with the copra supports during the application of a shock load, as a result of which the destruction of the sample occurs along the glued connection by tearing off the layers of wood. " - and? name) sh» -i 1 sl 60 b5