**6. Tension**

*Truss and Frames - Recent Advances and New Perspectives*

A mechanical type-universal test machine (UTM) is obtained for the tension or compression test. UTM is DTU-900MHA and a mechanical type with a digital signal processor (DSP) system as shown in **Figure 4**. For the tension test, **Figure 5** shows experimental setup in the UTM. It shows uniaxial tensile test with specimen made by aluminum ally, AlSi10Mg. **Figure 5(1)** is a specimen before tensile test and **Figure 5(2)** shows a specimen after the tensile test. **Figure 5(2)** shows a circle which means zoom-out as the right figure. The right figure shows a good tested result in the specimen, because it is broken in middle area in the specimen

*Uniaxial tensile test with specimen made by aluminum alloy AlSi10Mg. Test speeding is set up as 1 mm/min:* 

*(1) shows a specimen before testing; (2) shows a specimen after testing.*

**5. Experimental setup**

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**Figure 5.**

**Figure 4.**

*Universal test machine (UTM) with data collector system.*

Making a tensile specimen is based on ASTM E8M standard. The specimens were obtained by AlSi10Mg power with the DMSL technique. Each section defined as a letter which shows dimensions on **Table 3**. **Table 3** shows rectangular shape of tension test specimens with detail dimensions like the gauge length, width, thickness, radius of fillet, overall length, length of reduced section, a length of grip section, and an approximate width of grip section. Thus, DMLS made specimens for the tension test.

Totally, three samples made by aluminum alloy (AlSi10Mg) marked as 2–1, 2–2, 2–3 were ready for the tension test, and they were tested by uniaxial tensile testing.

**Figure 6** shows specimens after tensile test and results with (a) engineering stress-engineering strain for all specimens and (b) stress-strain for 2-2 specimen. As you can see, 2–2 specimen shows clearly that the middle point was broken. Others were broken in an area of top point or bottom point. Thus, tested data were selected for 2–2 specimen because it shows a good fracture.

From the tension test, engineering stress-strain and true stress-strain can be defined as shown in **Figure 6**. **Figure 6** shows a comparison between engineering stress-strain and true stress-strain for aluminum alloy AlSi10Mg.


#### **Table 3.**

*Rectangular tension test specimens based on ASTM E8M.*

#### **Figure 6.**

*Stress as a function of Stain for Aluminum alloy specimen after tensile test; (a) Engineering stress - Engineering strain for all specimens, and (b) Stress-strain for 2-2 specimen.*


#### **Table 4.**

*Mechanical properties of AlSi10Mg by tension.*

In order to do the tension test for AlSi10Mg, it is defined material properties are as follows: Young's modulus is 71.81GPa, yield strength is 155.52 MPa, and ultimate tensile strength is 348.32 MPa approximately. These are summarized in **Table 4**. When the Young's modulus value is compared in **Table 2**, they almost matched in vertical direction. That is, it is proved that tensile specimen is created in vertical direction by DMLS.
