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Stress and Strain
Published in Ansel C. Ugural, Mechanical Engineering Design, 2022
Stress due to the restriction of thermal expansion or contraction of a body is called thermal stress, σt. Using Hooke’s law and Equation (1.21), we have σt=α(ΔT)E
Materials Selection Process
Published in Mahmoud M. Farag, Materials and Process Selection for Engineering Design, 2020
The environment in which the product or component will operate plays an important role in determining the material performance requirements. High or low temperatures, as well as corrosive environments, can adversely affect the performance of most materials in service, as discussed in Chapters 2 and 3, respectively. Whenever more than one material is involved in an application, compatibility becomes a selection consideration. In a thermal environment, for example, the coefficients of thermal expansion of all the materials involved may have to be similar to avoid thermal stresses. In wet environments, materials that will be in electrical contact should be chosen carefully to avoid galvanic corrosion. In applications where relative movement exists between different parts, wear resistance of the materials involved should be considered. The design should provide access for lubrication; otherwise, self-lubricating materials have to be used. The selection of materials to resist failure under different service conditions is discussed in Chapter 4.
Stress and Strain
Published in Ansel C. Ugural, Youngjin Chung, Errol A. Ugural, Mechanical Engineering Design, 2020
Ansel C. Ugural, Youngjin Chung, Errol A. Ugural
Stress due to the restriction of thermal expansion or contraction of a body is called thermal stress, σt. Using Hooke’s law and Equation (1.21), we have σt=α(ΔT)E
Formation of functionally graded hybrid composite materials with Al2O3 and RHA reinforcements using friction stir process
Published in Australian Journal of Mechanical Engineering, 2022
Chandra Vikram Singh, Praveen Pachauri, Shashi Prakash Dwivedi, Satpal Sharma, R. M. Singari
Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. To identify the thermal expansion, dimensions of all the prepared composites were kept 625 mm3 (25 x 5 × 5). All prepared composite samples were kept in a muffle furnace at 450°C constant temperature for 48 h (Dwivedi and Mishra 2019). Thermal expansion test of the sample for tensile strength obtained at optimum parameters was calculated. Volume difference was found to be 2.5 mm3 for tensile strength sample and 1.5 mm3 for hardness sample obtained at optimum tool parameters as shown in Figure 12. From this result, it can be concluded that Al6063 and Al8011 composite reinforced with Al2O3 and RHA can be used in a high-temperature environment.
Structural Analysis of Induction Machine and Switched Reluctance Machine
Published in Electric Power Components and Systems, 2019
Lizon Maharjan, Shiliang Wang, Babak Fahimi
Change in temperature causes expansion in material at a rate determined by the coefficient of thermal expansion. The coefficient of thermal expansion for the selected material (i.e., Structural steel), is 1.2× This expansion introduces thermal stress if the object is externally or geometrically restricted to expand. The expansion and stress experienced can be calculated using Eqs (7) and (9), respectively [19, 20]. The simulation results have been confirmed by comparing the axial stress experienced by the outer disk presented in Figure 2 when the temperature of the entire body is increased from 22 to 82 °C. The result is presented in Table 1. The disk movement has been restricted by fixing two laminar faces and inner cylindrical face. where, = final length, = initial length, = temperature rise, = strain, = stress, = Young’s modulus.
2-D FEM thermomechanical coupling in the analysis of a flexible eRoad subjected to thermal and traffic loading
Published in Road Materials and Pavement Design, 2023
Talita De Freitas Alves, Thomas Gabet, Rosângela Motta
The thermal expansion characterises the capacity of materials to dilate or contract respectively due to increase or decrease of temperature. The thermal coefficient α is defined as the rate of change in the original unit (length, area or volume) of a material per degree of change in temperature, at a constant pressure: Where and represent, respectively, the original and final lengths associated to the temperature change from to . The coefficient α is conventionally described with units of reciprocal temperature (°C−1).