Week 11 Pre-Class

When a viscoelastic material is loaded and unloaded, the unloading curve is different to the loading curve, i.e. it takes more energy to displace the material than it does to return the material to its original configuration. This is known as: Select one: O a. creep O b. stress relaxation O c. hysteresis d. strain-rate dependance

Question 2 Figure 2 shows the dependence of fatigue strength on testing cycles (S-N curve) of an acetal polymer. 60 50 40 30 20 10 104 105 106 107 108 Number of cycles to failure Figure 2 The S-N fatigue curve for an acetal polymer a. What is the fatigue strength, or maximum stress amplitude, at one million cycles of loading? b. An acetal polymer 30-cm-long bar with a diameter of 20 mm is designed to survive one million cycles of loading, what is the maximum allowable axial load that can be applied on one end of the bar? Magnitude of stress Reversal, MPa

Biomaterial question: Give a brief and clear answer, please do not write by hand Question: Sketch a typical stress-strain curve for three major types of biomaterials. Describe Young’s modulus and write Hooke’s Law.  What are the time-dependent properties of materials? Explain briefly.

What are the units of the elastic strain energy release rate?

Sketch Figure 1.3, curve b (a ductile metal). Label it with the following terms, indicating from which location on the curve each quantity can be identified or extracted: elastic region, plastic region, proportional limit, tensile strength, onset of necking, fracture stress.

Make sure you do the sketch

Please do the Sketch if not please do not respond. This question have been answered wrong already

A Cotton fiber, initially 2.2 cm long, is being stretched to its maximum known strain. What would be its final length, in cm, before rupture?

1. Sketch stress-strain curves for the following three materials (mechanically worked tungsten metal, annealed tungsten metal, and tungsten carbide) on the same plot. On each curve, label the following: ultimate compressive strength (UCS), yield stress (YS), modulus of elasticity (E), and rupture stress (RS).

1. For the stress-strain curve shown below, please estimate the properties indicated. (a) Fracture Strain Please do your work on a separate sheet of paper, and put your answers in the boxes on the right. Be sure to include the proper symbol and units. Stress Strain 70 60 50 Stress (ksi) 240 30 20 10 70 0 0.000 60 50 Stress (ksi) 40 20 10 KULL 0 0.000 0.010 0.050 0.100 Strain (in/in) Stress Strain 0.020 0.030 Strain (in/in) 0.040 0.150 0.050 (b) Ultimate Tensile Stress (c) Fracture Stress (d) Proportional Limit (e) Elastic Modulus (1) Yield Stress (g) Tensile Toughness (Modulus of Toughness) (h) Modulus of Resilience

the behaviour of  sponge material under stress

During stress-strain test, the unit deformation at a stress of 35 MPa was observed to be 167 x 10^-6 m/m and at a stress of 140 MPa it was 667 x 10^-6. If the proportional limit was 200 MPa, what is the modulus of Elasticity (GPa)? What is the strain corresponding to a stress of 80 MPa?

QUESTION 7 Which governing equations are required to solve a plane elasticity problem? Boundary conditions Equilibrium condition and boundary conditions Equilibrium conditions, boundary conditions, and the compatibility equation QUESTION 8 Which of the following conditions must a structure meet to produce a state of plane strain parallel to the x-y plane? Thin-walled Uniform in z-direction Dimension in z-direction that is much smaller than x and y QUESTION 9 What is the major advantage of using the Airy stress function for plane isotropic solids? Reduces the governing equations to only the boundary conditions and compatibility equation Reduces governing equations to a single function with a single unknown QUESTION 10 Airy stress functions are applicable for solving all elasticity problems. True False

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4. For a brass alloy, the stress at which plastic deformation begins is 345 MPa and the modulus of elasticity is 103 GPa. What is the maximum load that may be applied to a specimen with a cross-sectional area of 130 mm² without plastic deformation? b. If the original specimen length is 76 mm, what is the maximum length to which it may be stretched without causing plastic deformation?

Q: For a bronze alloy, the stress at which plastic deformation begins is 280 MPa, and the modulus of elasticity is 115 GPa. (a) What is the maximum load that may be applied to a specimen with a cross-sectional area of 325 mm? without plastic deformation? (b) If the original specimen length is 120 mm, what is the maximum length to which it may be stretched without causing plastic deformation?

For a brass alloy, the stress at which plastic deformation begins is 345 MPa, and the modulus of elasticity is 103 GPa. Determine the following (a) What is the maximum load that may be applied to a specimen with a cross: sectional area of 130 mm2 without plastic deformation?(b) If the original specimen erngth is 76 mm, what is the maximum length to which it may be stretched without causing plastic deformation?

2) For a brass alloy, the stress at which plastic deformation begins is345 Mpa and the modulus of elasticity is 103GPa.a) What is the maximum load that can be applied to a specimen with area130mm² cross section without plastic deformation? b) If the original length of the specimen is 76 mm, what is themaximum length to which it can be stretched without causing deformationplastic?

1. What are the elastic modulus (E) and the Poisson's ratio () used to indicate? 2. Illustrate the differences between actual stress and engineered stress with strain, and also describe their underlying physical concepts. 3. If the engineering strain is 2% for a specific state of uniaxial stress, what is the real strain?   Please solve for all in full detail and step by step

No wrong answer please , i could downvote The piece of suture is tested for its stress relaxation properties after cutting 3 cm long sample with a diameter of 1mm. The initial force recorded after stretching 0.1 cm between grips was 5 Newtons. Assume the suture material behave as if it has one relaxation time. The gage length was 1 cm. a. Calculate the initial stress. b. Calculate the initial strain. c. Calculate the modulus of elasticity of the suture if the initial stretching can be considered as linear and elastic. d. Calculate the relaxation time if the force recorded after 10 hours is 4 Newtons.