In a piezoelectric cantilever, the poled directions of the piezoelectric layers are usually perpendicular to the planar direction of the piezoelectric layers because it is the most convenient way to polarize piezoelectric sheets when they are fabricated. Piezoelectric cantilevers operating in the above manner are said to be operating in the “31 mode,” where “3” denotes the polarization direction of the piezoelectric layer and “1” denotes the direction of the stress, which is primarily material, d31 is always smaller than d33 because in the 31 mode the stress is not applied along the polar axis of the piezoelectric material [3]. Therefore, in order to utilize a piezoelectric sheet in the “d33” mode for higher energy output, an interdigitated …show more content…
Application of an electric field across the ceramic creates a mechanical strain, and in a similar manner, application of a mechanical stress on the ceramic induces an electrical charge [4]. The fundamental component of a piezoelectric stack actuator is a wafer of piezoelectric material sandwiched between two electrodes. Prior to fabrication, the wafer is polarized uniaxially along its thickness, and thus exhibits significant piezoelectric effect in this direction only. A typical piezoelectric stack actuator is formed by assembling several of the wafer elements in series mechanically and connecting the electrodes so that the wafers are in parallel electrically, as illustrated in figure 5 [4]. The nominal quasi-static behaviour of a piezoelectric stack actuator is a steady-state output displacement that is monotonically related to the voltage …show more content…
Thus, a structronic shell is an active and adaptive system whose static and dynamic characteristics can be actively tuned and controlled to meet its performance requirement as uncertain circumstances occur [5]. Piezoelectric shells, continua, and distributed systems have been investigated for years and their theories and mathematical models are relatively well established. Electrostrictive effects in ferroelectric material were first observed in early 50s. Electrostrictive shells were initially evaluated and mathematical models were established. Unlike the linear dependence of piezoelectric materials, the induced strain in electrostrictive material is a quadratic function of applied electric field [5]. The low hysteresis and the high induced actuation authority of electrostrictive actuators would potentially contribute a breakthrough in actuation and control applications. However, there are certain ferroelectric materials, e.g., barium titanate (BaTiO3), possessing dual electrostrictive and piezoelectric characteristics depending on the Curie
Elastic strain region at small and big end of connecting rod is shown in figure no. 10. The maximum and minimum equivalent strain values are 0.00033975 and 2.1407e-10 respectively. Due to applied pressure there will be change in original dimensions of the connecting rod and hence strain developed can be
According to Suspension bridges: Concepts and various innovative techniques of structural evaluation, “During the past 200 years, suspension bridges have been at the forefront in all aspects of structural engineering” (“Suspension”). This statement shows that suspension bridges have been used for over 200 years, and that people are still using them today because they are structurally better bridges. This paper shows four arguments on the advantages of suspension bridges, and why you should use one when building a bridge. When deciding on building a suspension bridge, it has many advantages such as; its lightness, ability to span over a long distance, easy construction, cost effective, easy to maintain, less risk
Some ceramics are used in orthopaedic applications such as bone repair, bone augmentation and joint replacement but their use in this field is not as extensive or widespread as metals and polymers because ceramics have poor fracture toughness. This severely limits the use of ceramics in load bearing applications (Davis, 2003).
An unbelievable idea has turned into reality. An idea that can now be born with the use of a 3D printing mechanism.
In the previous section, the governing equation of the dynamic and stability behavior of the nanobeam are derived. The Eq. (19) and Eq. (20) are the fourth order partial differential equations which are obtained as the governing equation of the vibration and buckling of the nanobeam, respectively. If it is not impossible to solve these equations as analytically, it is very hard to solve these equations as exact solutions. For this purpose, for computing the vibration frequencies and the buckling loads, the differential quadrature method is selected. The real reason of this selection is because that this method is one of the useful methods to solve the ordinary and partial boundary value and initial
The inner workings of the turntable may seem complex at first but after reading this paper it should become clear that, like all things, the record player works on basic principals of physics. In fact, the turntable is remarkable in that the basic physical principles behind it are quite simple. Some of these will be explored here. Please enjoy your visit.
A transducer is a mechanism that changes one form of energy to another form. A toaster is a transducer that turns electricity into heat; a loudspeaker is a transducer that changes electricity into sound. Likewise, an ultrasound transducer changes electricity voltage into ultrasound waves, and vice versa. This is possible because of the principle of piezoelectricity, which states that some materials (ceramics, quartz, and others) produce a voltage when deformed by an applied pressure. Conversely, piezoelectricity also results in production of a pressure whe...
... Physics." .::. The Pysics of Electric Guitars :: Physics. N.p., n.d. Web. 26 May 2014. .
Mechanical Engineering 130.2 (2008): 6 - 7. Academic Search Complete. Web. The Web. The Web.
3D Printing: The weapon to save or kill? People nowadays might get the impression that the 3D printing technology is a relatively new concept in our daily lives. However, 3D printing technology has been invented and utilized in many fields such as creating human organs in healthcare, building architectural models in engineering, and even forming components that can be used in aeronautic fields. Since Charles W. Hull invented the 3D printing technology in the 1980s, scientists, engineers, and even normal people were and still are trying to discover more possibilities of the usages and changes in this technology. Same as every invention of the new technology, with its undeniable beneficial effects, 3D printing also faces lots of limitations on the printing material, financial costs, market standardization, and more crucially the possible abuse of it.
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This project will not look into creating and developing entirely new methods of construction in the New Zealand building industry. It will instead look at ways to utilise, expand on, and adapt methods of prefabrication which have already been developed (and proven to work in the New Zealand context) in a new way that will allow a high level of flexibility in the design/layout once the building has been constructed and is being occupied.
... middle of paper ... ... References Fletcher, N., Martin, D. and Smith, J. (2008) Musical instruments, in AccessScience, McGraw-Hill Companies, Retrieved November 25, 2011 from http://www.accessscience.com.ezproxy.hacc.edu. Henderson, T. (2011). The 'Standard'.
Produced sound from speakers has become so common and integrated in our daily lives it is often taken for granted. Living with inventions such as televisions, phones and radios, chances are you rarely ever have days with nothing but natural sounds. Yet, few people know the physics involved in the technology that allows us to listen to music in our living room although the band is miles away. This article will investigate and explain the physics and mechanism behind loudspeakers – both electromagnetic and electrostatic.
Smart materials are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli [8] that provide architects with more opportunity to design that are environmentally sustainable. According to early definitions, smart materials are materials that could respond to their environments in a timely manner [9]. With a look to characteristics of smart materials, we discover that they directly focus on their actuation events and the ability of prognosis, immediate response to the environmental conditions. The external stimuli, Light, Temperature, Pressure, Electric field, Magnetic field and Chemical environment [2] on smart materials cause different effect on smart materials. Addington and Schodek say “The behaviour of a material is dependent upon its interaction with an energy stimulus” [1]. Smart materials according their response to external stimuli classify to three groups: Property change, Energy exchange and Shape memory alloy [9]. Smart materials are often described as adaptive or intelligent materials [2]. Because of this adaptivity, also increases the option space for saving energy while at the same time supporting favourable comfort conditions [10]. With the aim of developing and encouraging appropriate energy policies for the future, it is required to gain an understanding of professional views in all countries, as well as those with extensive fossil fuel reserves [11]. Smart Materials are a particular type of materials that have recently received considerable attention in the international construction industry because they suggest the feasibility of preparing clean energy sources for buildings in aesthetically and architecturally fascinating ways