Mechanical
Get flash to fully experience Pearltrees
DoITPoMS - TLP Library
Teaching and learning packages ( TLP s) are self-contained, interactive resources, each focusing on one area of Materials Science. Analysis of Deformation Processes This TLP builds upon the introduction to yield criteria covered in the Stress analysis and Mohr's circle TLP and introduces a range of methods commonly used to study metal forming processes. Introduction To Anisotropy It is common in basic analysis to treat bulk materials as isotropic - their properties are independent of the direction in which they are measured. However the atomic scale structure can result in properties that vary with direction.
injection molding
Granta: CES Selector materials selection software
CES Selector—support critical material and process choices. Optimize cost, performance, and environmental impact. CES Selector™ is a powerful PC software application that offers extensive materials property data, advanced graphical analysis, and specialist tools to support materials selection and substitution decisions. Support early stage design, eco-design, and redesign of products —identify optimal materials and structures prior to detailed modeling, leading to a reduction in design iterations. Enable material comparison, replacement, and substitution —reveal differences in performance and highlight risks associated with changing materials, enabling rapid yet well-informed decisions.
Level 1 Chapter 5: Materials Section 5.1: Introduction to laser machining of metals Section 5.2: Introduction to laser machining of polymers Section 5.3: Introduction to laser machining of composites Section 5.4: Introduction to laser machining of semiconductors Section 5.5: Conventional laser machining of materials Section 5.6: General materials issues considered in laser machining procress References Level 2 Chapter 5: Materials Section 5.1: Introduction to laser machining of ceramics Section 5.2: Introduction to laser machining of metal-matrix composites Section 5.3: Introduction to laser machining of superalloy Section 5.4: Laser machining by Doubled and tripled frequency Yag lasers Section 5.5: Short pulse high density laser machining Section 5.6: Diode pumped laser machining of materials References Level 3 Chapter 5: Materials Section 5.1: Diode Laser machining Overview Section 5.2: Ultra-short pulsed laser machining Section 5.3: Three Dimensional Micro-structuring in materials
Untitled Document
To describe elastic properties of linear objects like wires, rods, or columns which are stretched or compressed, a convenient parameter is the ratio of the stress to the strain, a parameter called the " Young's modulus " or " Modulus of Elasticity " of the material. Young's modulus can be used to predict the elongation or compression of an object as long as the stress is less than the yield strength of the material. 1 N/m 2 = 1x10 -6 N/mm 2 = 1 Pa = 1.4504x10 -4 psi 1 psi (lb/in 2 ) = 144 psf (lb f /ft 2 ) = 6,894.8 Pa (N/m 2 ) = 6.895x10 -3 N/mm 2 Note!
Elastic Properties and Young Modulus for some Materials
July 2011
And now a word from the government! In honor of the 4th of July celebration here in the US I am taking a break from our discussion about "less is more" to focus on major initiatives to move the cause of green manufacturing forward - these from the government. The discussion on "less is more" will continue with part 3 next time. We've heard a lot about some of the major corporations and the initiatives they've taken to enhance the sustainability of their organizations and influence their supply chain. One of the first that comes to mind is Walmart and their efforts to insure the products they sell, and their operations delivering them, are "more efficient, last longer and perform better." There are many more players in this field and a simple glance at Environmental Leader or GreenBiz website will give a great introduction and allow you to track their progress.Soft-feel grain surface treatment
This technology gives hard-surface plastics a soft and moist feel at a much lower cost even than "soft-feel" paint by imposing a "grain" or texturing onto the surface. It has application in automotive interiors, household utensils, electronics, mobile phones, and other locations where a hard plastic surface would benefit from feeling softer. The science is based on the study of the fingerprint.
Ultra Light Metal-like Material
Inspired by large lattice-style modern buildings such as the Eiffel Tower, the material is made up of nickle phosphorus tubes that create a micro-lattice consisting of 99.9 percent air. The wall of the hollow tubes are 1000 times thinner than a human hair, yet are extremely strong and resistant to strain. The new material could have applications in the automobile industry, and could reduce material demands worldwide.
Researchers have dispersed tiny platelets of aluminum oxide in apolymer to make a material that is tough, stretchy, and lightweight.The material could lead to longer-lasting bone and dental implants andlighter, more fuel-efficient car and airplane parts. It could also beused to make bendable, transparent electronics. In their efforts to create strong yet light materials, chemists andmaterials scientists have long tried to mimic nanostructures found innature. Shells, bones, and tooth enamel all consist of stiff ceramicplatelets arranged in a polymer matrix like bricks in mortar. Thesehybrid materials combine the strength of ceramics and thestretchability of polymers. Nanocomposite of aluminum oxide and a polymer is as tough as metals but lighter
Strong, Light, and Stretchy Materials
Dragon skin bulletproof vest repels AK-47 rounds
These bulletproof vests are the first to stop armor piercing rounds without using some bulky plate. They work better than traditional shit beat cops use because the fibers are woven tighter; and they're woven in a way that actually tightens up the weave upon impact by bullet or blade. They're soft enough to roll up into a ball, and are certified for dives, so they're appropriate for amphibious missions. These bulletproof vests have tighter woven fibres 3034 viewsThe fabric is made from tixotropic yarn. Under normal conditions, the crosslinking bonds of the fabric's dilatant silicone coating open and re-form easily, keeping the material soft and flexible. However, under sudden impact, these bonds are unable to open.
Tixotropic textile
Belt friction is a term describing the friction forces between a belt and a surface, such as a belt wrapped around a bollard . When one end of the belt is being pulled only part of this force is transmitted to the other end. The friction force makes that the tension in the belt can be different at both ends of the belt.
Belt friction
Driving or slack side tension (T2) To determine the minimum tension which must be introduced into the belt as it leaves the driving pulley, to ensure that the effective tension or power can be transmitted into the belt passing around the drive pulley, without slip. Prior to going into this analysis, it is necessary to understand the effect that friction and wrap angle have on the driving characteristics of a pulley. These are discussed below :- (a) Friction Factors The fundamental equation for conveyor drive calculations is: T 1 / T 2 = e θ Figure 1: Typical Drive Pulley Where:
Belt Tension Theory: Factors
1. Non-linear rotary drive apparatus, comprising, in combination: first rotatable member means having a geometric center and an axis of rotation spaced apart from its geometric center for providing non linear rotational speed as the member means is rotated; second rotatable member means disposed adjacent to the first rotatable member means; cable means coupling the first and second rotatable member means together for joint rotary movement; and
Patent US4796478 - Non-linear rotary drive apparatus - Google Patents
Patent US5105672 - Rotary drive apparatus having one member with smooth outer peripheral surface - Google Patents
1. Rotary positioning apparatus comprising, in combination: drum means having a generally smooth outer peripheral surface and having a first axis of rotation and having a first diameter; shaft means disposed adjacent to the drum means and having an outer peripheral surface and having a second axis of rotation generally parallel to the first axis of rotation and having a second diameter which is substantially less than the first diameter; and cable means, including a multistranded and coated cable, secured to the drum means and extending helically about the outer peripheral surface of the drum means, helically onto and about the outer peripheral surface of the shaft means, and back onto and helically about the outer peripheral surface of the drum means of greater than 360 degrees of the drum means for coupling together the drum means and the shaft means for joint rotation of greater than 360 degrees of the drum means. 2.Worm Gears
Introduction A worm gear is used when a large speed reduction ratio is required between crossed axis shafts which do not intersect. A basic helical gear can be used but the power which can be transmitted is low.detachable