How Many Ways Can You Break an Egg?

This is the question we recently pondered with Ken Zuckerman of Pete & Gerry's Organic Eggs.

We tested 3 types of their eggs: Organic, Nellies Cage Free, and Marans Heirloom. Testing with a electromechanical testing system using compression platens the breaking force ranged from 37 lbf to 62 lbf. The Organic eggs broke with the least force - 37 lbf, while the Nellies broke with an average of 54 lbf. The mahogany Marans heirloom eggs were the strongest no matter which way we tested them.

Take a look at the video to see the tests. Read more

Question from a Customer

Q. How should I approach rheological testing with a new polymer?

A. The optimization of rheological tests is iterative; the best way to determine the most ideal testing conditions is to experiment with the material. That said, there are some basic questions that we can ask ourselves about the polymer in order to speed up the optimization process:

1. Is it thermoplastic or thermosetting? I would have serious reservations about performing a test on a thermoset; great care should be taken to discover the conditions that bring on thermosetting and then to meticulously avoid those conditions while testing.

2. Do we know the optimum temperature range for processing of the polymer? Many materials are listed in tables of Melt Flow Rate data, and temperature information from these tables is transferrable for use in a Capillary Rheometer. The key is to enable stable flow while imposing the intended processing conditions. If the material flows in an unstable manner, the temperature should be raised; if the material shows degradation, the temperature should be lowered. Temperature change should be of the order of 5-10 degrees per attempt and the selection of optimum processing temperature should be made on the basis of satisfactory performance of the extrudate. This may take several attempts.

3. How viscous is the material? Highly viscous polymers will need a large diameter capillary so that the test is not confined to a very low shear rate by the limitations of the pressure transducer. Conversely, low viscosity polymers, such as PVA, require the use of a much smaller die so that the barrel is not emptied before the test is complete. Often MFR data can help in making these decisions.

4. What pressure transducer shall I use? Until the first test is complete, it won’t be clear how much pressure the fluid will exert under test conditions. The most highly rated pressure transducer should be fitted; if the chosen transducer is too delicate it may be damaged. The results of this test will be of very low resolution, but will be accurate enough to determine a more appropriate choice.

5. What if I want to do a Bagley correction? A Bagley correction is a test using two barrels that calibrates the machine against the effects of barrel-die geometry. Because the Bagley correction is specific to the testing parameters under which it is performed, it is worth waiting until appropriate testing conditions are agreed upon before performing one. Additionally, initial tests should be run on a single bore. This in case the testing conditions prove to be inappropriate and the test must be aborted. Having filled only one barrel, only one barrel of material is wasted and less cleaning is required. Read more

Finding the Right Test Type

Part two of Why Test Composites touches on finding the right test type for your application. We cover the basics in this article; if you have more specific questions you'd like answered, leave us a comment below.

Composites are complex structures made from a variety of different plastic, metal, and ceramic materials. The mechanical and chemical integrity of composite materials are affected by many variables making property prediction and analysis challenging. Testing is a vital adjunct to analysis, as well as being essential for quality control. 
Rheology
The study of the rheological behavior of thermo-plastic based composites is very important for fabrication of end products and plays an important role in determining the material performance related to deformation and flow under the processing conditions. Capillary Rheometers measure the rheological behavior of thermoplastic polymers and composites under processing conditions. Melt Flow Testers measure, with great accuracy, the MFR and MVR - basic data required for thermoplastic quality control in the raw materials field.

Thermo-Mechanical
HDT & VICAT systems are used to characterize the behavior of plastic materials at high temperatures, measuring the heat deflection temperature (HDT) and the Vicat softening temperature (Vicat). These thermal testing systems range from very simple units for quality control labs to more advanced and automated systems.

Tensile     
Tensile testing of composites is generally in the form of basic tension or flat sandwich tension testing in accordance with standards such as ISO 527-4, ISO 527-5, ASTM D 638, ASTM D 3039 and ASTM C 297. A range of proven gripping solutions is available for ambient, sub-ambient, and high temperature testing. The gripping mechanisms include manual, pneumatic, and hydraulic actuation. A range of jaw face patterns are available to provide effective gripping of tabbed and un-tabbed specimens. This allows for no slipping under load and no premature failure caused by stress concentrations in the jaws. Hydraulic grip solutions for non-ambient testing place the hydraulic components outside the temperature chamber, for safety and reliability. Adapters are available to allow other accessories, including compression platens, and bend fixtures, to be attached while leaving the grips in place.

Compression
Compression tests can be conducted on plain or “open/filled hole” specimens.  Common testing standards include: ASTM D 695, ASTM D 3410, and ISO 14126. Compression fixtures are designed to meet the unique requirements of composite materials providing precise alignment and precision guidance to prevent buckling.

Compression After Impact
Significant advances in damage tolerant composites include the addition of sheets between plies and additives to the resin. A Compression After Impact (CAI) test helps develop and prove these damage tolerant composites and also the repeatability of their performance. A drop tower is required to provide the impact before a compression test is conducted on a testing machine. Standards include: Airbus AITM 1.0010, ASTM D 7136 and D 7137, SACMA 2R-94, and Boeing BSS 7260. Watch a video on CAI.

Flexure
The most common flex testing of composites is 3-point and 4-point bend testing to ISO 14125, ASTM D 790, and ASTM D 6272. 

Shear
Interlaminar, rail, in-plane Iosipescu, and flat sandwich in-plane shear tests can be performed to meet standards: ISO 14129, ASTM C 273, ASTM D 5379, and ASTM D 4255. ASTM D 2344 and ISO 14130 can also be met using an interlaminar flexural and shear testing fixture.

Fatigue
An extensive range of dynamic systems accommodates loads from < 1 - 2500 kN, ideal for meeting the  fatigue and fracture testing requirements of composite materials – especially in demanding applications such as aerospace and wind power. It’s important to note that the load frames need to provide high stiffness and exceptional alignment that composite testing demands.

Other Mechanical Tests
A variety of other standardized mechanical tests on composite materials are available. Examples include bearing strength tests to ASTM D 5961 and interlaminar fracture toughness tests to ASTM D 5538. Read more

Why Test Composites?

Composite materials are being used in an ever-increasing variety of products and applications as more and more industries realize the benefits and advantages that these materials offer as they strive to manufacture structures that are lighter, stronger and offer greater corrosion resistance than those made from traditional materials. As the demands for light-weight structures for the aerospace and automotive industries develop, along with environmentally sustainable energy systems, the physical and mechanical testing requirements for materials and components extend too. Composite materials and components require a range of physical mechanical testing, under a range of environmental conditions, including high-force tension and compression, impact, flexure, shear, rheology, and fatigue.

Mechanical testing instruments are configured with a range of fixtures that have been developed to provide various ways of testing composite materials depending on the type of material and its intended end-use. Most of these fixtures are designed to meet specific materials testing standards. These standards have been developed over the years by leading manufacturers and research organizations, and then made their way into ASTM, ISO, EN, and other standards. In addition, auditing bodies, such as Nadcap, dictate performance criteria, for example alignment for the testing equipment.

Material Properties – structural variables such as fiber orientation, fiber volume fraction, laminate thickness, and core density; and processing variables such as layup accuracy, curing temperature and pressure can have a dramatic effect on the mechanical properties of composite materials. Mechanical and process testing is necessary to understand the effect these variables have on the finished material or component.

Reliability – for use in high-performance applications in the aerospace, automotive, and motorsport industries, material testing is required to prove the reliability and repeatability of component properties.

Damage Tolerance – testing is necessary to simulate real-life conditions such as tool drops, minor accidents, and manufacturing imperfections.

Research and Development – testing is performed to investigate variables that will effect mechanical properties, damage tolerance, and provide data for finite element analysis. Read more

Developing Employees & Solutions

Accelerating the development of current employees not only instills confidence within that employee, but it adds so much value to the company. The Gordan Engineering Leadership Program "broadens the employees skill set and gives them a deeper understanding of your company's position in the market".

One of our newest engineers, Morgan Galaznik, attended this program at Northeastern University, graduated in August, and became Instron's first Gordon Fellow - congratulations Morgan!

Find out more about the challenges Morgan faced and the solutions she developed for Instron. Read more

Video: Capabilities in Materials Testing

Materials testing is an interesting field of science - discovering the potential of multiple materials for use in such a wide range of industries: academic, automotive, biomedical, construction, defense, healthcare, and more. Everything we use in today's world is, at one point, tested for durability, strength, and resilience. Take a peek inside the world of materials testing at Instron.

Read more

Jostling in Judo

Judo, a martial arts represented at the Paralympic games, is more dramatic and competitive than normal when you consider that in the Paralympic version, the Judoka (the original Japanese word for exponents of Judo) are blind or visually impaired. Its system of throws, grapples, and take-downs lends itself to athletes who are visually impaired, but otherwise have no physical disability. With Judo mats that are typically textured, this helps aid the athletes in orientation around the arena.

It is these mats that provide the stability, traction, and impact absorption properties required to enjoy the sport safely. After all, take-downs hurt. Throws are as dramatic as being tossed over a shoulder, and sometimes, Judoka simply fall on their faces. To ensure that participants aren't injured during bouts, judo mats must be rigorously tested.

Read here to find out more about how martial arts equipment, in particular Judo mats, could be tested to international standards. Read more

Slamdunk Safely

After the second World War, many veterans returned with injuries that prevented them from leading the lives that they had led before the war. However, rather than allow this to stand in their way, a number of American veterans founded the sport of Wheelchair basketball as part of a program of rehabilitation.

Using very similar rules and regulations to basketball, Wheelchair basketball is every bit as intense and dramatic. The wheelchairs are specifically designed for resilience to the intense conditions seen on the court, but often last only six months. Even more significant is the risk of injury from competing in such conditions. Mouthguards are only recommended in the international rules, rather than required as mandatory wear. Without one, however, a simple fall could result in broken teeth and tongue injuries.

Even if an athlete does wear a mouth guard, how do they know that it will protect their teeth and tongue during falls and collisions? Read here for more on how drop towers could help. Read more

Blades of “Steel” - Carbon Fiber Rowing Oars

With more than 500 athletes racing down the course with precision during the 2012 Olympic Rowing Competition, each stroke of the carbon fiber oars are vital as the boats soar significant distances to the finish line.
Introduced in 1976, carbon fiber oars have significantly enhanced the sport of rowing. These oars enable crews to push their boats to faster speeds and to perform with extreme precision. Originally, crews used wooden oars that were bulky, stiff, and heavy (weighing 14 kilograms). Carbon fiber oars are lightweight (only weighing 5 kilograms) and can be tailored to athlete's specific needs.

Carbon fiber blades are produced by compression molding, which utilizes extreme heat and pressure to generate high-strength objects. First a fabrication of carbon fiber, pre-impregnated fiberglass and syntactic foam are poured into a heated compression mold (like a giant waffle iron). Then the mold is closed with nearly 6,350 kilograms of force. Once the blade has cooled, it is trimmed, painted with a design, and finished with coat of epoxy. Finally, the blade is tested for strength, flexibility, and durability to ensure maximum power and precision on race day. Read more

A Unique Sport

Goalball is an eccentric sport unique to the Paralympic games and is played by athletes with a visual impairment. Much like soccer, each team attempts to get the ball into the other team’s goal.  This is where the similarities end, however. In order to level the playing field completely, all competitors must wear eye-shades to completely black out their vision; the ball is perceived audibly and the court features a tactile surface to aid in orientation. The eyeshades must be thick enough to completely black out all light, strong enough to survive a rough sporting environment, and not cause significant discomfort to the competitor. Unfortunately, the process of injection moulding the eye-shades can leave flaws in the finished product:

• Bubbles can cause stress concentrations, which reduce the life-span
• Rapid solidification in the mould causes insufficient mould filling
• Elasticity of the melt during processing results in distortions
• Thermal degradation can affect the physical properties of the goggles, making them weaker

Injection Moulding is a popular choice for manufacturing high volume products, however, if it is not properly controlled, can lead to any number of the above flaws. Read here to find out how the CEAST SmartRHEO Capillary Rheometer can help your company enhance its injection moulding Research, Design, and Quality Control processes. Read more