fastspänd

Fastspänd is a Swedish adjective meaning secured, fixed, or clamped in place. It is used in everyday language and in technical contexts to indicate that something is held firmly so that it cannot move relative to its surroundings. In everyday use, a fastspänd belt means the belt is buckled; cargo may be fastspänd to a pallet to prevent shifting during transport.

In engineering and physics, fastspänd describes boundary conditions where a structure’s ends or points are restrained against translation and rotation, typically by bolts, welds, or rigid supports. A beam that is fastspänd at both ends is functionally clamped: the ends cannot rotate and deflection is zero at those points. This is contrasted with simply supported (pinned) or free ends. The choice of fastspända boundary conditions affects deflection, bending moments, and natural frequencies; fixed ends increase stiffness and raise natural frequencies relative to simply supported beams, and produce nonzero fixed-end moments when the beam is loaded.

Practical aspects include the need for proper joints, torque, welding, or mechanical clamps to maintain the fastspända condition under loading and over time. Improper clamping can lead to slippage, loosening, or fatigue. In design, boundary conditions are described as fastspända ends or fixed supports.

Other uses of the term appear in everyday Swedish to describe items that are secured, such as a fastspänd seat belt or cargo that is strapped down. The concept is common in manuals, engineering standards, and safety guidelines, where clear indications of how components are secured influence performance and safety.