Today's KNOWLEDGE Share:COMPRESSION LOADING in Plastics

 Today's KNOWLEDGE Share:

COMPRESSION LOADING in Plastics

Compression is the application of a load on opposite surfaces of a structure to cause crushing. In reality, plastics rarely show catastrophic cracking in compression. However, failure may be classified by the degree of distortion from the original shape due to the compressive stress. 

This type of failure is commonly seen as:

· Creep when the component distorts and takes a permanent set, such as the flattening of an appliance caster.

· Stress Relaxation when the component loses inference with a mating part, such as a gasket.

A notable exception here are thermoset plastics, which can shatter in compression, and often demonstrate true compressive rupture failure.

More commonly, plastics will continue to compress to a flat disk as the applied stress increases, without fracture. In many instances, the application of compressive loading results in deformation of the part, such as buckling or bending, producing corresponding tensile loads at other locations.

The common responses to compressive loading are:

· Buckling

· Shearing

· Double barreling

· Barreling

· Homogeneous compression

· Instability

Compression of plastics is tested per ASTM D 695. As per the standard, a specimen is placed between two parallel plates on a universal testing machine (UTM). Load is applied in order to move the plates together at a specified rate. The load cell records compressive stress, while displacement is measured from crosshead movement. The test results in a plot of stress versus strain.

The compressive strength of a material is the force per unit area that it can withstand in compression. Plastic resin suppliers generally report compressive yield strength, the stress measured at the point of permanent yield, zero slope, on the stress-strain curve. The analogous test to measure compressive strength in the ISO system is ISO 604.

Typically, the compressive modulus and yield stress are usually greater than the corresponding tensile values.

Source:Jeffrey A. Jansen

Sustainable high-end luggage

 Overcoming the conventional:

Launched in 2015, HORIZN STUDIOS was Europe’s first direct-to-consumer travel brand. Focused on innovative design, convenience, and sustainable solutions, it was the first company in the world to release luggage with a removable charging function.

In 2021, however, HORIZN STUDIOS was looking to really revolutionise luggage design. Despite the challenges of the global pandemic, the company intended to create the world’s most sustainable luxury luggage. Embracing a philosophy of lightweight, high-performance, and sustainable materials, HORIZN STUDIOS sought out a partner that would be able to simultaneously fulfil these demanding criteria.

Natural fibre composite technologies

Already proven in the unrelenting world of motorsport and the equally challenging arena of ultra-high-end furniture, Bcomp’s innovative ampliTex™ and powerRibs™ are ground-breaking carbon-neutral composite reinforcements made entirely from flax fibre.

Cultivated across Europe, flax is an indigenous plant that has been part of the agricultural industry for centuries. With low water and nutrient requirements and little need for pesticides and fertilisers, it is a popular rotational crop with excellent utility – useful for feed, making flax oil, and its fibres can be used in textiles.

ampliTex™ and powerRibs™ make the most of flax’s inherent mechanical properties, creating composite parts with high stiffness, resistance to breakage, torsion, and compression – perfect to form the shell of tough and sturdy luggage. Using appropriate care and processes, Bcomp’s materials also offer a flawless surface finish, suitable for luxury product applications.

Most importantly, ampliTex™ and powerRibs™ are some of the most sustainable composite technologies available today, particularly in the high-performance category. Analysis of past projects has shown that Bcomp’s technologies can provide a material emission reduction of 90% when compared to its most commonly used equivalent, carbon fibre. Overall, they offer an outstanding 80-85% cradle-to-gate emission reduction, while retaining many of the performance benefits.

Unlike other luggage materials that would be sent to landfill at the end of their useful life, the Circle One range has various end-of-life recycling options thanks to Bcomp’s flax fibre composite technologies. ampliTex™ also opens up the possibility of repair, rather than replace, something of great interest to the HORIZN STUDIOS team.

Source:bcomp.ch/JECCOMPOSITES

Today's KNOWLEDGE Share:The first CARBON CONCRETE house

 Today's KNOWLEDGE Share:

The first CARBON CONCRETE house

The Technische Universität Dresden has now reached a new milestone: The world's first carbon concrete house "Cube“ has been completed on the university campus.

Their brand new "carbon concrete" is created by reinforcing concrete with carbon fibers, and for the production of carbon concrete, up to 50,000 of these fibers are woven into a rod or matte-shaped structure, which then serves as reinforcement for the concrete.

In contrast to steel, carbon does not have to be protected from moisture because carbon cannot RUST. As a result, much less concrete has to be used in a carbon concrete building than in steel. With new construction principles that are still under development, up to 80 percent of concrete should be saved in the end. The CO2 emissions that are saved in the production of the building material or through the reduced use of concrete are up to 50 percent.

The Cube makes it clear: carbon concrete opens up completely new design options for a house and for architecture. As visual conspicuity, the carbon concrete house has been given a twisted roof made entirely of carbon concrete. The building material has a high degree of flexibility and is even more stable than reinforced concrete. Another advantage is longevity: a carbon concrete house should be usable for up to 200 years – a reinforced concrete building, on the other hand, only 40 to 80 years.

Source: DasHaus .de/#managingcomposites/#thenativelab

Today's KNOWLEDGE Share:LIFE CYCLE ASSESSMENT OF TEA CUP

 Today's KNOWLEDGE Share:

LCA:

Have you ever thought that life cycle assessment (LCA) is a bit of a minefield? Let’s start with a cup of tea!

Whether you want to benchmark your product against another, find the hotspots in your supply chain or comply with your customer’s Environmental Product Declaration (EPD) requirements, understanding the basics of LCA methodology is increasingly important to avoid greenwashing.

Source:Enrique J Garcia

Today's KNOWLEDGE Share:Carbon fiber 3D woven joints

 Today's KNOWLEDGE Share:

Carbon fiber 3D woven joints

3D woven joints and preforms are widely used in aircraft, missiles, satellites, spacecraft, helicopters, vehicles and more. By means of the low cost, fast production and lightweight solutions, 3D woven carbon fiber composites are the products of the present and the future!

What are the advantages of using 3D woven composites, instead of common 2D laminated composites?

- They can be directly woven into complex net shapes
- Allows higher fiber volume
- Improved impact resistance and Compression After Impact
- Yarns can be controlled according to stability, strength and shape desired in the end product
- Possibility to choose different fiber types such as carbon fiber, aramid, glass etc. in the weaving process
- Practically zero delamination between the layers
- Reduce the cost of composite parts production

Source: Erginer Ceramic and Composites Technology/# managingcomposites

ECHA Includes Nine New Hazardous Chemicals to Candidate List

 European Chemicals Agency (ECHA) adds nine chemicals in the Candidate List because of their hazardous properties. They are used for example in flame retardants, paints and coatings, inks and toners, coating products, plasticizers and in the manufacture of pulp and paper.

233 Entries in the Candidate List:

ECHA’s Member State Committee confirmed the addition of these substances to the Candidate List. The Candidate List now has 233 entries – some are groups of chemicals, so the overall number of impacted chemicals is higher.

These substances may be placed on the Authorisation List in the future. If a substance is on that list, its use will be prohibited unless companies apply for authorization and the European Commission authorizes them to continue its use.

Entries added to the Candidate List on 17 January 2023 are as follows:

1) 1,1'-[ethane-1,2-diylbisoxy]bis[2,4,6-tribromobenzene]

2) 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol

3) 4,4'-sulphonyldiphenol

4) Barium diboron tetraoxide

5) Bis(2-ethylhexyl) tetrabromophthalate covering any of the individual isomers and/or combinations thereof

6) Isobutyl 4-hydroxybenzoate

7) Melamine

8) Perfluoroheptanoic acid and its salts

9) reaction mass of 2,2,3,3,5,5,6,6-octafluoro-4-(1,1,1,2,3,3,3-heptafluoropropan-2-yl)morpholine and 2,2,3,3,5,5,6,6-octafluoro-4-(heptafluoropropyl)morpholine

Consequences of the Candidate List:

Under REACH, companies have legal obligations when their substance is included – either on its own, in mixtures or in articles – in the Candidate List.

Suppliers of articles containing a Candidate List substance above a concentration of 0.1 % (weight by weight) have to give their customers and consumers information to be able to use them safely. Consumers have the right to ask suppliers whether the products they buy contain substances of very high concern.

Importers and producers of articles will have to notify ECHA if their article contains a Candidate List substance within six months from the date it has been included in the list (17 January 2023). Suppliers of substances on the Candidate List, supplied either on their own or in mixtures, have to provide their customers with a safety data sheet.

Under the Waste Framework Directive, companies also have to notify ECHA if the articles they produce contain substances of very high concern in a concentration above 0.1 % (weight by weight). This notification is published in ECHA’s database of substances of concern in products (SCIP).

Source: ECHA/SPECIALCHEM

Today's KNOWLEDGE Share:REINFORCEMENTS

 Today's KNOWLEDGE Share:

Reinforcements:

What is the effect of reinforcement type on the strength properties of fiber reinforced composites?

This insightful graph shows how different reinforcements (like short fibers, mats, fabrics, and unidirectional fibers) can increase the strength properties of composite materials!

Source:managingcomposites