Image Image Image Image Image Image Image Image Image Image
Scroll to top

Top

Problem Solving in Nature and TRIZ

Comparing Problem Solving in Nature and TRIZ
Editor

By Ali Reza Mansoorian

Abstract

This article compares TRIZ solutions to design in nature (bionical solutions) and looks for the relationships between them. Bionical solutions can help withTRIZ tools and improve the ability of TRIZ to solve problems.

Keywords

TRIZ, nature, bionics, bionical creatology, bionical creativity engineering, inventive problem solving

Introduction

Biology solved engineering problems since the appearance of life on earth. Design and function in plants and animals have been optimized under evolutionary pressures over millions of years – one small step at a time. These long lead times do not fit easily with the more frenetic pace of the engineering world of today.

Time scales may be different but today’s design constraints and objectives are similar: functionality, optimization and cost effectiveness. Therefore, it is not surprising that engineering has always admired biological structures and often been inspired by them; we can appreciate their aesthetically attributes as well as their engineering and design content.

Bionical creatology, as a scientific sub-discipline of creatology, deals with the technical transformation and application of structures, procedures and developmental principles of biological systems. “Bionics” derives from the terms “bio” and “technique.” Today, the word is more generally used for the young interdisciplinary research field that combines biology with engineering sciences, architecture and mathematics and can be defined as an approach for determining the aim, the method used and the solution to a problem or opportunity.

Nature, with its great variety of efficient structures, is a source for the stimulation of ecologically sound and ergonomic solutions to problems and opportunities. Examples in nature can be creative elements within the process of producing a solution to a problem. The rules of biological evolution can be used both for determining the aims and the principles of functions of structures and organizations, as well as providing a model for determining solutions. The bionical approach is seen as reducing the gap between the man-made world and nature.

Bionical Solutions: Birds

Most birds (e.g., kites, eagles, vultures and storks) have characteristically slotted wingtips. The primary feathers, or winglets, of birds of prey (raptors) respond to the aerodynamic forces acting on them during flight by bending up and becoming staggered in height. In a single wing this has the effect of reducing the induced drag by spreading the vortices in the tip region and, therefore, keeping the friction drag low in the inner part of the lift generating system. The multi-winglet configuration of the bird’s wing is, however, effectively a multiple wing system, and this beneficial effect becomes somewhat counterbalanced by an increase of the friction drag.

By using the contradiction matrix and inventive principles we find:

Improving factor: volume of moving object
Worsening factor: energy spent of moving object
Proposed principle(s): 35 (transformation of physical and chemical state of object)

Improving factor: area of moving object
Worsening factor: energy spent of moving object
Proposed principle(s): 19 (periodic action) and 32 (changing the color)

Improving factor: convenience of use
Worsening factor: energy spent of moving object
Proposed principle(s): 1 (segmentation), 13 (inversion), 24 (mediator)

Strategy used by birds: segmentation (Spread wing-tips of the birds as a model for drag reduction.)

Figure 1: Segmentation in Birds

Bionical Solutions: Strain Sensors

The cricket Acheta domesticus has two specialized structures at the end of its abdomen, which are called “cerci.” There are up to 3,500 sensors on each 2 mm cerci of the adult cricket. Insects use perturbation of the airflow field over their bodies (pressure changes and vibrations) to detect prey and/or predators. This is achieved using highly specialized hair sensors. About 300 of the sensors are specialized, detecting changes in air flow. They consist of a hair 300-3000µm in diameter, which is anchored into a socket.

Often one or more strain sensors are located around the socket. Other specialized sensors detect gravitational pull, chemicals, deformation or contact.

Applications of Bionical Systems

  1. Understanding this complex sensory system will eventually allow us to employ the biological function and mechanical properties of the hairs into Micro Electro Mechanical Systems (MEMS) to create a miniature hybrid model.
  2. Insects and arthropods have extraordinary sensitive mechanosensors to detect deformations in their exoskeletons. Local modifications of the laminated composite structure of the cuticle are used for mechanical strain amplification.
  3. The chitin fiber architecture around the sensing canals of insects and arthropods can be replicated in man-made composites to introduce integral deformation sensing functions at minimal loss of stiffness and strength. The integration between the mechanical, neurological and signal processing aspects is being investigated to provide information for MEMS-based technologies.

By using the contradiction matrix and inventive principles we find:

Improving factor: accuracy of measurement
Worsening factor: complexity of device
Proposed principle(s): 26 (copying), 2 (extraction), 18 (mechanical vibration)

Strategies used by insects:

  1. Mechanical vibration sensor
  2. Synergy of many sensor (not a TRIZ principle)
  3. Combination
  4. Composite materials
Figure 2: Sensors in Insects

Bionical Solutions: Spiders Silk

One major application of bionical engineering is in the field of biomaterials, which involves mimicking or synthesizing natural materials and applying them to practical design. There are many examples of materials in nature that exhibit unique useful properties. One of the major advantages of biomaterials is that they are normally biodegradable. In addition, the extreme temperatures and hazardous chemicals often used in man-made construction are usually unnecessary with natural alternatives.

Spider silk is one of the most sought after biomaterials, gaining a reputation as the “Holy Grail” of biomaterials. This material, produced by special glands in a spider’s body, has the advantage of being both light and flexible, and pound for pound is roughly three times stronger than steel – the tensile strength of the radial threads of spider silk is 1,154 Mpa while steel is 400 Mpa. The web is composed of two types of silk: 1) the major ambulate silk, which forms the dragline and web frame and 2) the viscid silk, which forms the glue-covered catching spiral.

For a flying insect to be caught, the spider’s web must slow its motion to a halt by absorbing kinetic energy. The force required to stop the insect’s motion is inversely proportional to the distance over which the motion must be stopped. The longer the distance over which the insect is slowed down, the smaller the force necessary to stop it, reducing the potential for damage to the web.

The incredible properties of spider silk are due to its unique molecular structure. X-ray diffraction studies have shown that the silk is composed of long amino acid chains that form protein crystals. The majority of silks also contain beta-pleated sheet crystals that form from tandemly repeated amino acid sequences rich in small amino acid residues. These amino acid sequences are composed of an 8-10 residue poly-alanine block and a 24-35 residue glycine-rich block. The resulting beta-sheet crystals crosslink the fibroins into a polymer network with great stiffness, strength and toughness. This crystalline component is embedded in a rubbery component that permits extensibility, composed of amorphous network chains 16-20 amino acid residues long. It is this extensibility and tensile strength, combined with its light weight, which enables webs to prevent damage from wind and their anchoring points from being pulled off.

Despite the high demand for spider silk as a building material, the difficulties surrounding its harvest have precluded large scale production. A new biotechnology firm in Quebec, Nexia Biotechnologies, has successfully expressed the silk genes of two spider species in the milk of a transgenic goat. The scientists expressed the genes, found by researchers at the University of Wyoming, using somatic cell nuclear transfer (the process used in mammalian cloning). The manner in which mammary glands create the long amino acid chains found in milk enables the formation of spider silk. Afterwards, the silk can be precipitated from the milk, and the result is a web-like material called BioSteel. This technology could have applications in the field of medicine as a new form of strong, tough artificial tendons, ligaments and limbs. Spider silk could also be used to help tissue repair, wound healing and to create super-thin, biodegradable sutures for eye or neurosurgery, as well as being used as a substitute for Kevlar.

By using the contradiction matrix and inventive principles we find:

Improving factor: force
Worsening factor: weight of nonmoving object
Proposed principle(s): 18 (mechanical vibration), 13 (inversion), 1 (segmentation), 28 (replacement of a mechanical system)

Improving factor: power
Worsening factor: weight of nonmoving object
Proposed principle(s): 19 (periodic action), 26 (copying), 17 (moving to a new dimension),
27 (inexpensive short-life instead of an expensive durable one)

Improving factor: power
Worsening factor: energy spent of nonmoving object
Proposed principle(s): N/A

Improving factor: strength
Worsening factor: weight of nonmoving object
Proposed principle(s): 40 (composite materials), 26 (copying), 27 (inexpensive short-life instead of an expensive durable one), 1 (segmentation)

Strategies used by spider:

  1. Composite materials
  2. Nesting
  3. Combination
Figure 3: Structure of a Strand of Spider Silk

Bionical Solutions: Shark Skin

Shark skin is very rough – in fact it is so rough that dried shark skin can be used as sanding paper. The skin is covered by little v-shaped bumps, made from the same material as sharks’ teeth. The rough surface has been shown to reduce friction when the shark glides through water, which is why sharks are quick and efficient swimmers. Fabrics modeled on shark skin are designed to reduce drag by channeling the water along grooves in the fabric. These grooves allow the water to spiral in microscopic vortices, a hydrodynamic advantage.

After looking at shark skin, NASA pioneered the use of longitudinal riblets (ridges perpendicular to the surface), to reduce drag on the flat surfaces of ships and aircraft. Riblets were used successfully to reduce drag on the ‘Stars and Stripes’ America’s Cup yacht and were thought to offer such an advantage that riblets were banned from competition for subsequent events. Shark skin itself is far more complex than simple longitudinal riblets.

By using the contradiction matrix and inventive principles we find:

Improving factor: volume of moving object
Worsening factor: energy spent of moving object
Proposed principle(s): 35 (transformation of physical and chemical state of object)

Improving factor: power
Worsening factor: energy spent of moving object
Proposed principle(s): 16 (partial, overdone or excessive action), 6 (universality), 19 (periodic action), 37 (thermal expansion)

Improving factor: area of moving object
Worsening factor: energy spent of moving object
Proposed principles: 19 (periodic action) and 32 (changing the color)

Improving factor: convenience of use
Worsening factor: energy spent of moving object
Proposed principles: 1 (segmentation), 13 (inversion), 24 (mediator)

Strategies used by shark skin:

  1. Segmentation
  2. Local quality
  3. Periodic action

Conclusion

Bionical engineering and TRIZ are important in all disciplines of science and engineering; they play strategic roles in researching development and innovations. Combined, they are powerful tools for creative problem solving, innovation, invention, quality development, productivity, etc.

Comparing solutions of TRIZ and solutions of nature (bionical engineering) are important for creative problem solving and help engineers create new ideas. The inventive principles of TRIZ are more powerful when aided by the with inventive principles of nature.

References

  1. Altshuller, G. S., 1984, Creativity as an Exact Science: The Theory of the Solution of Inventive Problems, New York: Gordon and Breach Science Publishers.
  2. Mansoorian, Ali Reza, 2005, Research Project for Iran Research Center of Creatology, Innovation & TRIZ.
  3. Mansoorian, Ali Reza, 2003, “Bionical Creativity Engineering,” Journal of Khalaghiat Shenasi (Creatology), Karafrini & TRIZ, Iran Research Center for Creatology, Innovation & TRIZ, No: 1, 22.
  4. Vincent, J.F.V. and Mann, D.L., 2002, “Systematic Technology Transfer from Biology to Engineering,” Philosophical Transactions of the Royal Society of London Series, Mathematical, Physical and Engineering Sciences, 360: 159-173.
  5. Vincent, J.F.V., 2000, “Deployable Structures in Nature Center for Biomimetics,” The University of Reading, U.K.
  6. Savransky, S.D., Engineering of Creativity, Introduction to TRIZ Methodology of Inventive Problem Solving, CRC Press, 2000.
  7. Mansoorian, Ali Reza, “Integrating TRIZ and Bionical Engineering,” The TRIZ Journal, March 2004.
  8. Golestan, Hashemi, Mahdi, S. & Mansoorian, Ali Reza, 2005, Bionical Creatology: Bionical Creativity Engineering, Malek Ashtar University Publisher.