Design
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Brittle fracture explained
Brittle fracture is a failure mode in materials that occurs without significant prior deformation, typically when a material is exposed to stress at a lower temperature, high loading rate, or in a material with high strength and low ductility. This type of fracture involves rapid crack propagation with minimal plastic deformation, often resulting in a…
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Creep and rupture explained
Creep is a time-dependent deformation that occurs when a material is subjected to constant stress at a high temperature (usually above about times its melting temperature, in Kelvin). Unlike elastic or plastic deformation, which occur almost instantaneously upon loading, creep deformation develops gradually over time. Creep is especially relevant for materials in high-temperature applications like…
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Plasticity explained
Plasticity is the property of a material that allows it to undergo permanent deformation under an applied load, beyond its elastic limit, without fracture. It is a crucial concept in solid mechanics, particularly in materials that can endure large deformations, like metals. 1. Elastic vs. Plastic Deformation 2. Yield Criteria To determine when a material begins to…
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Hertzian contact explained
Hertzian contact stresses describe the localised stress distribution that occurs when two curved surfaces (e.g., spheres, cylinders, gears) are pressed against each other. This theory, developed by Heinrich Hertz in the late 19th century, is used to predict the behaviour of materials under compressive loads where contact is made over a small area, like in…
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Eccentric column buckling
When the geometrical centre of area (centroid) of a column does not correspond to the load path, the situation introduces eccentric loading, which can lead to additional bending moments along with axial compression. Here’s how you can approach the buckling analysis in this case: 1. Determine Eccentricity (e): 2. Calculate the Total Stress: Where: 3. Account for Buckling Using…
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Torsion springs
A torsional spring is a mechanical device that works by storing and releasing rotational energy. It resists twisting or rotational motion and exerts a torque in the opposite direction of its displacement. Unlike traditional compression or extension springs, which store energy in a linear fashion, torsional springs store energy through angular or rotational displacement. Key Features of…
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Extension springs
Extension springs are tightly wound coils designed to operate with a pulling force, meaning they stretch when force is applied and return to their original length when the force is removed. These springs store mechanical energy in the form of tension, which makes them useful in various applications where resistance to elongation is required. Structure…
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Compression springs
Compression springs are a type of mechanical spring designed to resist compressive forces. When a load is applied to a compression spring, it compresses and stores mechanical energy, which can then be released when the load is removed. They are among the most common types of springs and are used in a wide range of…
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Mechanical springs
Mechanical springs are elastic components used to store energy and absorb shock. Here is a summary of the main types of mechanical springs: 1. Compression Springs 2. Extension Springs 3. Torsion Springs 4. Constant Force Springs 5. Variable Force Springs 6. Leaf Springs 7. Disc Springs (Belleville Springs) 8. Gas Springs 9. Wave Springs 10. Die Springs 11. Rubber Springs (Elastomeric Springs) Each type of spring…
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Beyond L10
In addition to loading level, several other factors are considered when assessing bearing life. These factors are critical for accurate prediction and optimisation of bearing performance in various applications. Here’s a detailed look at these factors: 1. Bearing Material and Quality 2. Bearing Type and Design 3. Operating Speed 4. Mounting and Alignment 5. Environmental Factors 6. Lubricant Condition and Replenishment…