CN102564283A - U-shaped frame for deflection test of bending test of wood structure beam - Google Patents

Abstract

The invention discloses a U-shaped frame for a deflection test of a bending test of a wood structural beam. The U-shaped frame is characterized in that a downward-concave trapezoid structure is arranged at the middle along the length direction of the U-shaped frame; two positioning holes are formed in two ends of the U-shaped frame; and the total length of the U-shaped frame is 300-12000mm. The U-shaped frame has the advantages of simple structure, convenience for operation, uniformity and standard in distribution of measuring points and accuracy and stability in data determination; and the U-shaped frame is made of light metal section and the aims of simplifying operation procedures of the test and realizing convenience, quickness, standard and accuracy are achieved.

Description

U-frame for bending test deflection testing of timber structural beams

technical field

The invention relates to a test device of a wooden structure, in particular to a U-shaped frame used for testing the deflection of a wooden structure beam in a bending test. the

Background technique

In the "Standards for Test Methods of Wooden Structures" GB/T50329-2002, the provisions for the deflection test device of the bending test of wooden structure beams are as follows:

4.3.4 The device for testing deflection should meet the following conditions:

1 When the test beam deflects under load, a U-shaped deflection test device can be used. The U-shaped device should meet the requirements of light weight and sufficient rigidity, and can be made of light metal (such as aluminum). The two ends of the U-shaped device should be nailed to the neutral axis of the beam, and a dial indicator is installed in the center of the device to measure the deflection of the neutral axis of the beam. the

2 When the span of the beam is very large, the deflection of the beam can also be obtained by directly measuring the displacement values at both ends of the beam and at the center of the span by using a deflection meter. the

Although the standard stipulates that the U-shaped device is used to measure the deflection, it does not specifically specify the size, specification, structure, and material of the deflection device, and there is no finalized product on the market, which makes it inconvenient to test the deflection in the wood structure experiment. the

Contents of the invention

The purpose of the invention is to overcome the deficiencies in the technical background and provide a deflection test frame for testing flexural strength, shear strength, flexural elastic modulus, and shear elastic modulus of wooden beams. the

The present invention is realized through the following technical solutions. the

A U-shaped frame used for deflection testing of wooden beam bending tests, characterized in that a concave trapezoidal structure is provided at the middle position along the length direction of the U-shaped frame, and a positioning bracket is provided at each end of the U-shaped frame. hole; the distance L1 from the positioning hole to the end of the U-shaped frame is 10 mm to 300 mm, the distance L2 from the positioning hole of the U-shaped frame to the first turning point of the U-shaped frame is 0-1000 mm, and the distance from the first turning point of the U-shaped frame to the U-shaped frame The distance L3 at the second turning point of the U-shaped frame is 0-5990mm, the bottom edge L4 of the concave trapezoid in the middle of the U-shaped frame is 0-11980mm, and the distance h from the upper edge of the U-shaped frame to the lower edge of the U-shaped frame is 10mm-600mm , the total length of the U-shaped frame is L=2×(L1+L2+L3)+L4, which is 300mm～12000mm, and the angles of the four turning angles of the U-shaped frame are θ, 0°<θ<180°;

When L3=0, L1, L2, L4≠0 or L2, L3=0, L1, L4≠0, all turning angles of the U-shaped frame are 90°;

When L4=0, the U-shaped frame becomes a V-shaped test frame in the middle. the

The optimum value of L2 is 300mm-600mm. the

The optimum value of L3 is 500mm-1500mm. the

The optimal value of L4 is 300mm-1000mm. the

The optimum value of h is 150mm-450mm. the

The apertures at both ends of the U-shaped frame are 1 mm to 20 mm. the

The invention has the beneficial effects of simple structure, convenient operation, uniform and standard distribution of measuring points, and accurate and stable measurement data. In order to achieve the purpose of simplifying the test operation process, convenient and fast, standardized and accurate. the

Description of drawings

Fig. 1 is a schematic diagram of the shape and specifications of the U-shaped frame of the present invention. the

Detailed ways

The U-frame used for measuring the deflection in the bending test of the wooden structure beam of the present invention is made of a light metal section bar by adopting a conventional production preparation process. the

The present invention can adopt aluminum alloy, iron alloy, copper alloy, also can adopt angle aluminum, angle steel, angle iron or section bar with suitable cross-section shape as manufacturing material, in order to arrange dial indicator in the middle position of U-shaped frame conveniently. the

Referring to Fig. 1, the present invention is provided with a sunken trapezoidal structure along the middle position of the length direction of U-shaped frame, and the two ends of U-shaped frame are respectively provided with a positioning hole, and the aperture of positioning hole is 1mm～20mm, and the positioning hole to The distance from the end of the U-shaped frame is L1, the distance from the positioning hole to the first turning point of the U-shaped frame is L2, the distance from the first turning point of the U-shaped frame to the second turning point of the U-shaped frame is L3, and the distance between the middle position of the U-shaped frame The bottom edge of the concave trapezoid is L4, the distance from the upper edge of the U-shaped frame to the lower edge of the U-shaped frame is h, and the total length of the U-shaped frame is L=2*(L1+L2+L3)+L4. the

L1 is 10mm-300mm, the optimum value of L2 is 300mm-600mm, the optimum value of L3 is 500mm-1500mm, the optimum value of L4 is 300mm-1000mm, the optimum value of h is 150mm-450mm, and the total length is L It is 300mm～12000mm, and the angles of the four turning angles of the U-shaped frame are 0°<θ<180°. the

The corners of the U-shaped frame are made of materials with the same thickness, size and material, and are connected by bonding, riveting or welding. the

The U-shaped frame of the present invention is fixed on the specified position of the wooden structure beam according to the "Test Method Standard for Wood Structure" during the bending test of the wooden structure beam, and the deflection change of the wooden structure beam during the loading process is measured at the full span and the pure bending section. The two deflection change data measured by the device can be used in the calculation of the flexural elastic modulus and the shear elastic modulus of the wooden structure beam. the

Claims (6)

1. a U type frame that is used for timber structure beam deflection test deflection test is characterized in that, is provided with a recessed trapezium structure along the centre position of the length direction of U type frame, and the two ends of U type frame respectively are provided with a pilot hole; The distance L 1 of said pilot hole to U type frame end head is 10mm～300mm; U type frame pilot hole to the distance L 2 of U type frame first turning point is 0～1000mm; U type frame first turning point is 0～5990mm to the distance L 3 of U type frame second turning point, and the recessed trapezoidal base L4 in U type frame centre position is 0～11980mm, and U type frame upper edge to the distance h of U type frame lower edge is 10mm～600mm; The total length of U type frame is L=2 * (L1+L2+L3)+L4; Be 300mm～12000mm, the angle of four deflection angles of U type frame is θ, 0 °＜θ＜180 °;

Work as L3=0, L1, L2, L4 ≠ 0 or L2, L3=0, L1, L4 ≠ 0 o'clock, all deflection angles of U type frame were 90 °;

When L4=0, the U type is put up the test stand that is V-shape for the centre.

2. according to the U type frame that is used for timber structure beam deflection test deflection test of claim 1, it is characterized in that the optimum value of said L2 is 300mm～600mm.

3. according to the U type frame that is used for timber structure beam deflection test deflection test of claim 1, it is characterized in that the optimum value of said L3 is 500mm～1500mm.

4. according to the U type frame that is used for timber structure beam deflection test deflection test of claim 1, it is characterized in that the optimum value of said L4 is 300mm～1000mm.

5. according to the U type frame that is used for timber structure beam deflection test deflection test of claim 1, it is characterized in that the optimum value of said h is 150mm～450mm.

6. according to the U type frame that is used for timber structure beam deflection test deflection test of claim 1, it is characterized in that the aperture at said U type frame two ends is 1mm～20mm.

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