By Abram Teplitskiy
Shape memory alloys (SMAs) are useful in construction; one such way is protecting buildings and other structures from earthquakes and other dynamic "happenings."
The two-way shape memory effect occurs when the material remembers two different shapes: at a low temperature and at a high temperature, whether internally or externally triggered. The reason the material behaves so differently in these situations lies in "training." Training implies that a shape memory can "learn" to behave in a certain way.
New applications of materials with shape memory effects were developed as protection from the dangerous consequences of earthquakes. During earthquakes significant amounts of energy are released, and too often the result is fatalities and structure destruction. Because of this potential for damage, engineers have long tried to invent methods and technical tools which could protect mankind. The structural integrity of a building or other structure can be increased and made more resistant to earthquake damage. A structural member is incorporated into a building structure, in which at least a portion of the structural member is made of a material that undergoes a shape or phase transformation in response to applied energy. This member can alter the natural frequency of the building structure to make destructive resonance less likely to occur.
The simplest tools to protect different erected and natural structures from earthquakes are simple, low cost, lightweight, energy-absorbing earthquake braces. One such application is based on installing braces inside structures for protection, like a child would seek in a mother's hands.
An invention demonstrating how spacers can assist with the ramifications from earthquakes was created with fibro-concrete three-dimensional blocks (Russian Federation Patent # 2,085,686). The blocks are put on reinforced concrete floors of all levels of a structure, and connected to each other by rebar. Besides this rebar, reinforced concrete floors also include special dampers or buffers.
Russian construction specialists in seismic protection applied for a seismic protection patent based on an idea from a Russian doll called Vanka-Vstanka (Figure 1). The center of gravity in a Vanka-Vstanka figure is located symmetrically along its central axis.
Russian Federation Patent # 2,196,211
Figure 2's purpose is seismic protection in particular dangerous regions. In this type of building, the upper levels are rigid while the floors have rounded corners (or hills or tables) made with sand, rubber, or other elastic or pillows. The floor, made from cross-like pillars with the properties of a Vanka-Vstanka (circled area), and formed by a pair of panels with rounded edges, are connected to each other by a system of grooves. The pillars thus have the ability to roll during earthquakes with the created variable curvature.
Russian Federation Patent #2,200,810
This transformation of technical effects, of material and substance, is applicable in areas beyond disaster prevention. Share any of your own experiments with The TRIZ Journal's audience.
Abram Teplitskiy, Ph.D., is a consultant for inventing, applied physics and civil engineering. Contact Abram Teplitskiy at tepl (at) sbcglobal.net.