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Mechanical Properties of Metals and Alloys
Published in Yip-Wah Chung, Monica Kapoor, Introduction to Materials Science and Engineering, 2022
Young’s modulus, also known as the elastic modulus, is a measure of the resistance against elastic deformation. It is defined as the slope in the initial linear portion of the stress-strain curve and depends on the direction along which the stress is applied. For example, the average value of Young’s modulus E for Fe is 205 GPa. However, the value of E is 280 GPa along the (111) direction and 125 GPa along the (100) direction. This implies that grains oriented along different crystallographic directions will have different resistance against elastic deformation, an important consideration in studying the deformation of polycrystalline materials.
Bonding and Properties of Materials
Published in Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu, Interdisciplinary Engineering Sciences, 2020
Ashutosh Kumar Dubey, Amartya Mukhopadhyay, Bikramjit Basu
The stiffer material consists of a quite steep slope at r = re, whereas the flexible material can be suggested to have shallower slopes. The fundamental differences in the elastic modulus of metals, ceramics, and polymers are due to their different types of bonding characteristics.1,4
Glass Containers for Parenteral Products
Published in Sandeep Nema, John D. Ludwig, Parenteral Medications, 2019
Robert Swift, Robert Schaut, Carol Rea Flynn, Roger Asselta
Similarly, as a material science term, elastic refers to the response of a material to the application and removal of a mechanical load that does not exceed the strength of the material. Elastic materials deform when loaded and then return to the original shape when the load is removed. The stiffness of a material can be characterized by its elastic modulus, also known as Young’s modulus, which is the ratio between the applied unit load, or stress, and the resulting unit deformation, or strain. In this respect, glasses are relatively stiff. Typically, the elastic modulus of glass is about the same as aluminum metal (5). Jiang et al. (90, 91) attached strain gages to the outer surface of glass vials to observe in real time the physical deformations of and corresponding stresses in the vials during freezing, frozen storage, and subsequent rewarming and thawing of various buffers and formulated drug products. Although it was not the objective of the studies, the work demonstrates the elastic deformation of the glass in response to the changing physical dimensions of the contents.
Improved output force response speed of the biological gel artificial muscle prepared from carboxylated chitosan and sodium carboxymethyl cellulose
Published in Mechanics of Advanced Materials and Structures, 2023
Junyao Wang, Tianhong Lang, Huan Liu, Yansong Chen, Lixiang Li, Yahao Liu, Weihua Zhu
To investigate the mechanical properties of BGAM, tensile tests are carried out with an electronic universal testing machine (KY-100NW) [19]. Figure 8(a) illustrates the stress-strain curves of BGAM with seven different crosslinking mass ratios. It can be noticed that the tensile deformation process only has an elastic phase, without yielding and necking phases. Moreover, the tensile stress is small and the tensile strain is large, which is a typical mechanical characteristic of gel materials. The elastic modulus is calculated from the stress-strain curve of the tensile experimental specimens (as in Figure 8b). It can be observed that the overall trend of the modulus of elasticity decreases and then increases. If the modulus of elasticity of BGAM is too large, large internal stress will be generated in bending, which increases the internal energy loss and reduces the electrically actuated performance [20]. However, if the modulus of elasticity is too small, the polymer material will be too soft, which will also reduce the electrically actuated efficiency. Consequently, an appropriate crosslinking mass ratio (#4) can reduce the elastic modulus and internal stresses of BGAM while avoiding a too soft polymer. This is one of the reasons why the response speed can be improved.
An evaluation of 3D printable elastics for post stroke dynamic hand bracing: a pilot study
Published in Assistive Technology, 2023
Justin Huber, Stacey Slone, Babak Bazrgari
The elastic modulus was measured using a tensile testing machine (Instron 5kN, Illinois Tool Works Inc., Norwood, MA, USA). This was done because the mechanical properties of plastics are known to change during processing (Zhu & Yang, 2020). For in-house tensile testing, 3DP material specimens were ordered from the manufacturers based on the dogbone specimen design, which is standardized for elastic materials (American Society for Testing and Materials, 2021). Of note, the 3DP dogbone specimens were ordered intentionally at the same time as the 3DP orthosis parts to promote consistency between the material undergoing tensile testing and the material assessed in the pilot study. For each 3DP material, five dogbone specimens were ordered and tested, and the average value served as the in-house measurement of elastic modulus (Figure 2).
Experimental evaluation of uniaxial strength and creep behavior of frozen gravel
Published in Journal of the Chinese Institute of Engineers, 2022
Yaqin Zhang, Ping Yang, Lin Li
The stress-strain curves of uniaxial compression test at the strain rate of 1%/min under different temperatures, as shown in Figure 2(a), are selected to illustrate the effect of temperature on frozen gravel strength. The stress-strain curves mainly consist of two stages: an approximate linear elastic stage and a strain-softening stage. The peak point is the cutoff point of the two stages. Before the peak point, the stress-strain curve is approximately a straight line, which indicates the material response is almost elastic. With the increase of the axial load, the axial stress increases dramatically to the peak value. According to the stress-strain curves under different temperatures, the slope of the straight line in this stage increases with the decrease of temperature. In other words, the elastic modulus increases with the decrease of temperature.