Torsion Of Shafts And Shear Modulus

Lab #1

Torsion of Shafts and Shear Modulus

Measurements

Prepared By:

Eduardo Hernandez

Group members: Javier Quirós

CE 335 – Civil Engineering Materials I

Lab Division 001

September 6, 2021

Compression Testing of Wood Eduardo Hernandez

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Synopsis/Abstract

The purpose of this lab was to enable students to use the MTS testing machine to apply

compressive loads onto wooden block samples in order analyze its compressive strength using the

raw data from the testing results. Additionally, students were required to distinguish the specific

failure on their wooden sample and characterize the strength of the material.

Introduction

Applied compression measurements obtained using the MTS testing machine and data

collected with the Test Works 4 software were used to determine the compressive strength of a

wooden specimen. The strength of a material can’t be directly measured. However, by calculating

its maximum load, we can use the specimen’s dimensions to calculate its maximum strength. Fig.

1 shows the MTS testing machine performing a test on one of the wooden specimens.

Fig. 1: MTS machine performing a compression test on a wooden specimen.

Compression Testing of Wood Eduardo Hernandez

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It is known that the strength of a material is equal to its maximum load divided by the

specimen’s cross-sectional area (width times thickness). With this in mind, we can calculate the

strength of different sizes of specimens and compare their results. In my case, the wooden

specimen measured 37.38mm (W) x 77.26mm (L) and it withheld 111.895 kN until it failed

experiencing a shearing failure as seen in Fig. 2.

Fig. 2: Wooden specimen showing a shearing failure after compression test.

This particular specimen was calculated to have a strength of 38.75 MPa. Although the general

average strength was 46.47 MPa, and my specimen was a little off, we could see that there is still

some variability within the data although most of the variables were kept constant. On the other

hand, we could conclude that specimens with a larger cross-sectional area carry a higher failure

load than those of a smaller one.

Compression Testing of Wood Eduardo Hernandez

Objectives

The objective was to experimentally study and analyze the compressive peak load and

crosssectional area relationship in a kiln-dried Douglas fir specimen with the MTS testing machine.

Failure modes of crushing, brooming, shearing, splitting, wedge splitting and combined shearing

and crushing specimens were also studied by allowing the material to fail.

Experimental Procedure

The lab had two different parts to the experiments. Part 1 of the lab involves three specimens