Measurement device of wood along-grain direction pure shear strength

Abstract

The invention provides a measurement device of wood along-grain direction pure shear strength. The measurement device mainly includes: a wood material having a V-shaped groove, which is arranged between two aluminum pieces at the left and the right and are bond to the two aluminum pieces to form an aluminum-wood composed beam, which is respectively connected to an upper transmission beam at the upper part and a lower pedestal at the lower part through connectors, thereby forming an integrated structure with the upper transmission beam and the lower pedestal. The apparatus can obtain an accurate result of shear strength of the wood and overcomes the defects of non-uniform shear force distribution on a shear rupture plane, stress concentration in concave angles, and bending stress on a rupture plane in shear test in wood specification, and overcomes the defects that the rupture in a test of measuring shear strength of the wood material with an Iosipescu shear apparatus directly does not occur in a theoretical rupture plane, the stress distribution at the left and right on a sample is asymmetric, deformation of the sample is intensive and the sample may slide.

Description

technical field [0001] The invention relates to the technical field of wood mechanical performance testing, in particular to a measuring device for the pure shear strength of wood along the grain direction. Background technique [0002] Wood is a complex porous, heterogeneous, and anisotropic material. It is widely used in many fields such as architecture and decoration because of its light weight and high strength. The anisotropic nature of wood is reflected in the fact that its mechanical properties along the grain direction (wood fiber growth direction) are much higher than those in the transverse grain direction. In order to use wood rationally and reliably in production and life, we must first have an understanding of its physical and mechanical properties. [0003] The mechanical properties of wood mainly include tensile strength, compressive strength, shear strength and flexural strength. Among them, the test methods of tensile strength, compressive strength and fle...

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Problems solved by technology

Many scholars have also tried to use it in the test of wood shear strength, but found that the results of the test are not ideal, mainly because: 1) The damage position of the wood block often does not occur at the theoretical damage surface, but first Cracks occur at the edge of the contact surface between the test device and the test piece; 2) The wood may undergo relatively large deformation before it is destroyed, which affects the stress distribution inside the test piece; 3) There may be slippage between the wood test piece and the test device. shift

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