Measuring bending stresses is an important part of structural engineering. Measuring bending stresses determines how much load a structure can support before it fails. Building structurally sound projects is the ultimate goal of successful structural engineering.
Measuring Bending Stresses
Measuring bending stresses requires determining the average amount of force exerted on an area that results in distortion or failure of the material. Understanding these values is crucial in determining the limits of construction materials.
Methods for Measuring Bending Stresses in Commercially Available Construction Materials
With the advent of new composite materials, measuring bending stresses has become a crucial ongoing investment of research dollars for scientists and engineers. One of the newest methods of measuring bending stresses is the use of piezoelectric PVDF (polyvinylidene-fluoride) film sensors.
Researchers have reported that a 25 µm thick PVDF strip used as an embedded interfacial stress sensor on aluminum and composite beams adequately measures bending stresses of the building materials. Engineers have also used these PVDF strips to measure other forces such as interfacial stresses and the adhesion strength of laboratory recreated layers of ice that might occur on the outside of a structure once constructed.
Another method of measuring bending stresses is to clamp gauges at key points of an existing structure to measure the bending moment of different types of materials used in the structure. By studying this data, scientists can learn vast amounts of information about the bending behavior of different construction materials once they are used in the field. This method also allows engineers to measure bending stresses over an extended period of time, allowing researchers to factor in other variables such as weather, corrosion, and alternating live loads.
Alternatively, engineers can measure bending stresses by attaching a hollow bar with strain gauges on its inner surface in a manner that allows part of the bar to move longitudinally along its axis with respect to the structure itself.
In Japan, researchers have experimented with measuring bending stresses in micro-cantilever structures by using a macro model using a micro-fizeau interferometer and the spatial fringe analysis method. Comparison of these test results with other measurements obtained from traditional gauge measurements shows that this method is effective in measuring bending stresses.
Other methods of measuring bending stresses indirectly are under consideration by the U.S. Patent Department and may revolutionize the way structural engineers study the measurement of bending stresses in the near future.