Smart Material Engineering Services
The engineers of Midé possess a unique, broad level of expertise when it comes to the application of smart materials. Smart Materials are materials that respond to changes in their environment and then undergo a material property change. These property changes can be leveraged to create an actuator or a sensor from the materials without any additional control or electronics required. Midé engineers understand the advantages and limitations of each material so the appropriate solution can be suggested for each of our customer’s applications. Midé has the experience necessary to source materials, design and fabricate prototypes, perform modeling and simulation, and manufacture products. The options of smart materials have a wide range as evidenced by the list below our sensor kit products.
Types of Smart Materials
Piezoelectric materials convert electrical energy to mechanical energy, and vice versa. They offer a wide range of utility and can be used as actuators (provide a voltage to create motion), sensors, such as many accelerometers, and energy harvesters since the charge generated from motion can be harvested and stored. Common applications for piezo materials are BBQ igniters and actuators for inkjet printer heads. Midé has successfully commercialized energy harvesters, haptic actuators, piezo valve actuators, and flow control devices.
Shape Memory Alloys:
The most commonly available Shape Memory Alloy is Nitinol, which was originally developed by the Naval Ordinance Laboratory. SMA’s have the ability to change phase as a function of temperature, and in that process generate a force or motion. They are capable of relatively high energy but move slowly. Typically applications include morphing structures, thermal triggers, and some high strain energy absorbing applications. Advanced materials still under development include magnetically activated shape memory alloys.
Similar to piezoelectric materials that respond to changes in electrical fields, this class of materials responds to changes in magnetic fields and can perform as an actuator, or sensor if deformed. While they can work well, they exhibit a large hysteresis which must be compensated when using the material in sensor applications.
Shape Memory Polymers:
Shape Memory Polymers (SMP) are similar to Shape Memory Alloys except the obvious fact they are made from a polymer matrix. They possess much greater recoverable strains than the alloys, but typically under lower forces. Morphing structures has been the area of greatest use to date for SMP’s.
Hydrogels can be tailored to absorb and hold water, or other liquids, under certain environmental conditions. Hydrogels have been around for a long time, specifically in disposable diapers. A key feature however is the gels can be tailored chemically to respond to different stimuli. Midé has also patented a method to embed the gels into a foam which enables systems to be built with the gels, such as the Hydrogel Activated Bulkhead Shaft Seals.
There are many forms of electroactive polymers and many are still being refined. They have great potential as the flexibility of how they can be used provide advantages over some of the metals and ceramics mentioned above. Most typically applications include energy harvesting and sensing (see Stretchsense development kit) however some researchers are looking at high voltage, low current actuators.
Adaptive thermal insulation can enable smart clothing that can change its thermal properties based on the environment. Midé has developed bi-component fiber technology where two different materials are co-extruded together to enable shape change depending on ambient temperature.