Birmingham Scientists, Dr Sakdirat Kaewunruen, PhD student Chayut Ngamkhanong and industry collaborator, Tianyu Yang have discovered New Unusual Phenomena That Help Explain Uncertainties in Spider Web Structures.
Photo of a spider web in a window
Birmingham scientists discover new phenomena that explain when and how networked structures such as spider webs, soft tissues, and membranes start to behave unusually.
It has been already well-known that “spider silk is one of the strongest materials for its weight, turns out to have another unusual property that might lead to new kinds of artificial muscles or robotic actuators,” many prominent researchers, including those at MIT, have found.
The team at Birmingham initially discovered by accident that the resilient extensible fibres respond very strongly to changes in the amplitudes of vibrations. Above a certain level of initial burden (stemmed from wind, atmospheric pressure, environmental and external load conditions), the networked structure suddenly changes the properties affecting the resonances and corresponding modes of vibrations. The initial findings have been reported in the journal Applied Sciences, in a paper by Birmingham scientist Dr Sakdirat Kaewunruen, from the School of Engineering, along with PhD student Chayut Ngamkhanong and former graduate student who now becomes the industry collaborator, Tianyu Yang. This work had won the Institution of Structural Engineers (Midlands)’s IStructE Research Award back in 2016.
The team has continued to observe even more unusual phenomena when imperfections exist in the networked structures such as spider webs. When the imperfect web structures are exposed to large amplitude precursors (e.g. large deformation, extreme load burden, etc.), the modes of vibration interact and appear to be dependent. This phenomenon is often referred to as ‘dynamic mode coupling’. These nonlinear phenomena can cause uncertainties in motion control, measurement and prediction. The new discoveries are being reported today in nature’s scientific reports, in a paper by Dr Sakdirat Kaewunruen, Chayut Ngamkhanong, and industry collaborator, Simiao Xu.
“The new findings discover a new phenomenon that has never been reported elsewhere” Kaewunruen says. These phenomena are commonly found in nature but have rarely been picked up by researchers.
“The outcomes could be very interesting for various communities such as structural, mechanical, bio-medical, or even defence teams” Xu, a senior engineer at Shanghai Posts and Telecommunications Designing Consulting Institute Co., Ltd. in Shanghai, China, says, as a novel way of predicting and controlling certain kinds of sensors, structural components, engineered materials, or control devices. “The applications of networked structures such as spider webs, structural membranes, catenary wires, satellites, and soft tissues are limitless”, Xu concluded.
Over many years, Professor Buehler and his team at MIT have reported that spider silk has its exceptional strength-to-weight ratio, its flexibility, and its toughness, or resilience. In fact, a number of research teams around the world are working to understand the behaviours of the spider webs. Through a combination of lab experiments and numerical modelings, they have been able to learn how the twisting mechanism works. Now that these new findings have been found, Kaewunruen suggests, it can explain why some experimental results show significant deviations and some uncertainties do exist due to modal crossovers. “Perhaps we can apply these phenomena to control the motions of networked structures and systems, especially when they experience a variety of internal and external burdens,” Kaewunruen says.
“We can find a variety of diverse potential applications. Many engineers can apply the concept of networked structures and systems to soft tissue, human muscles, soft robots, ultra-thin sensors, smart textiles and membranes, railway overhead catenary wires, or even greener energy generators.” Ngamkhanong points out. This discovery is very significant from a fundamental scientific perspective, and also very intriguing for applications.
The work is the collaboration between the University of Birmingham and Shanghai Posts and Telecommunications Designing Consulting Institute Co., Ltd. in Shanghai, China. This project has partially been supported by the European Union's Horizon 2020 research and innovation programme under grant agreement No 691135.
