Engineering is Awesome

Materials Testing: Tensile Tests

Extremely useful for determining various mechanical properties, the tensile test (or tension test, as it is also called) is one of the most common methods of materials testing. 

A tensile test is carried out by taking a sample of a material and subjecting it to increasing tension, stretching the sample until failure. This simple test results in the graph shown above (or something similar, depending on the material) called a stress-strain diagram. The elongation of the sample is determined with relation to the force required to produce such stretching and, knowing the cross-sectional area of the sample, the resulting stress and strain can be calculated and graphed.

This simple diagram gives a surprising number of mechanical properties, including the Modulus of Elasticity (or Young’s Modulus), yield strength, ultimate strength (also called ultimate tensile strength or tensile strength), and ductility (depending on the elongation before failure). Though less common, the stress-strain diagram can also be used to calculate the modulus of toughness and of resilience.

Along with the many properties that can be determined, another reason that tensile tests are so popular is that they can be used for almost any material. Depending on said material, the specimen is usually shaped similar to those in the bottom right image in what is called a ‘dog bone’ sample. The top left and bottom left images show brittle and ductile failure, respectively.

Sources: 1 2 3 4

Canadian engineering team Aerovelo just broke their own world record in the Eta, a recumbent bicycle fitted with a windowless, egg-like shell. Most of the incredibly efficient machine is built of carbon fiber. The engine is muscle, sweat and sinew – engineer Todd Reichert.

I’ve covered Aerovelo’s efforts before: in 2012, they were racing to build a human powered helicopter. They succeeded in 2013.

Here’s a video I made about their competitors, a team of graduate students and undergrads from the University of Maryland.

She never dreamed having her picture taken to recruit engineers would turn out to be a controversy.

When Isis Wenger agreed to be part of a recruiting campaign for engineers, she never imagined she’d face the controversy that arose.

What exactly was it about this image that had people clamoring to dissect her involvement? Did she say something messed up about engineering? Did she do something offensive in her pose?

All of the hubbub is over what she looks like. Because she’s a woman. 

Scientist Colin Furze Builds His Own Thermite Canon. 

Thermite is a metal powder that burns at around 2500 degrees C. Whether or not Colin made this canon to teach others about chemistry (or just to blow stuff up), it’s still really cool regardless.

New record in materials research: One terapascals in a laboratory

An international team of researchers headed by Prof. Dr. Natalia Dubrovinskaia and Prof. Dr. Leonid Dubrovinsky of the University of Bayreuth has succeeded in creating a pressure of 1 trillion pascals in a laboratory. A study published in Science Advances is opening up new research prospects in physics, solid state chemistry, materials science, geophysics, and astrophysics.         

The extreme pressures and temperatures that can be achieved and controlled with great precision in a laboratory are ideal objects of investigation in physics, chemistry, and materials science. They allow the structures and properties of materials to be explained, new materials to be synthesized for industrial applications, new material states to be discovered, and a deeper understanding of materials to be achieved, thereby yielding insights into the structure and dynamics of Earth and other planets. For this reason, scientists around the world have a strong research interest in continuing to increase the amount of pressure generated in laboratories for purposes of material analysis.

Ruchi Sanghvi (b. 1982) is an Indian engineer, and the first female engineer employed by Facebook. She was one of the primary developers for the Facebook News Feed, and was behind many initiatives and new products released by the social network over time.

Upsizing nanostructures into light, flexible 3-D printed metallic materials

For years, scientists and engineers have synthesized materials at the nanoscale level to take advantage of their mechanical, optical, and energy properties, but efforts to scale these materials to larger sizes have resulted in diminished performance and structural integrity.

Now, researchers led by Xiaoyu “Rayne” Zheng, an assistant professor of mechanical engineering at Virginia Tech have published a study in the journal Nature Materials that describes a new process to create lightweight, strong and super elastic 3-D printed metallic nanostructured materials with unprecedented scalability, a full seven orders of magnitude control of arbitrary 3-D architectures.

Strikingly, these multiscale metallic materials have displayed super elasticity because of their designed hierarchical 3-D architectural arrangement and nanoscale hollow tubes, resulting in more than a 400 percent increase of tensile elasticity over conventional lightweight metals and ceramic foams.

Verena Holmes (1889-1964) was an English engineer and inventor, the first woman elected to the Institution of Mechanical engineers. She also co-founded the Women’s Engineering Society in 1919, and advocated for more inclusion of the female gender in a traditionally male-dominated profession.