BSAS 330 Module 7.2 Discussion

Changes in cortical bone density and bone geometry occur with aging in both men and women (Table 1 from Russo 2003). These changes manifest as decreased bone strength, which has the clinical impact of increasing the risk of fracture with increasing age. However, elderly men are much less prone to fracture than elderly women. It has been suggested that age-related bone loss is the consequence of endosteal bone resorption resulting in changes in bone geometry (~2mm less cortical bone thickness in women as they age) and contributing to relative differences in fracture risk between men and women. Cortical bone area decreases in women between the ages of 20 and 85, whereas there is no significant change in cortical bone area for men over the same age range (Table 1). Table 1: Changes in bone density and cortical bone area - from Italian population of 612 men and 693 women Age group (years) ANOVA 20-39 Total bone density 4% (mg/cm³) Men Women Cortical bone area 38% (mm²) Men 318.9±47.9 Women…

Figure 1 shows the tensile testing results for different materials. All specimens have an initial diameter of 12 mm and an initial gauge length of 50 mm. 300 250 Low carbon steel Network polymer 200 Crystalline polymer 150 Amorphous polymer 100 50 5 10 15 20 25 30 Strain (%) Figure 1: Stress-strain curve b. Determine the following parameters for each material: • the tensile strength the 0.2% offset yield strength the modulus of elasticity • the ductility Stress (MPa) LO

In most cases a validation of the estimate is a sanity check' to ensure that the estimate is reasonable. What strategies and processes are used to conduct a validation of an estimate? Provide a brief explanation of each. (50-80 words)

A sample of crosslinked polvisoprene rubber undergoes a constant strain rate axial tension experiment The initial sample measurements are 3.60 cm gauge length (axial direction); 0.b2 cm wide; 0.1/ cm thick:

Simulated Annealing How would Simulated Annealing perform if the temperature, T, is always equal or very close to 0, where we omit the termination test (except that we terminate the search when a goal node, either a local or global optimum, is met)? Please pick up one option from the following options and explain.(a) A random walk(b) Hill-Climbing(c) It would halt immediately(d) It would never halt

The nuchal ligament in a horse supports the weight of the horse’s head. This ligament is much more elastic than a typical ligament, stretching from 15% to 45% longer than its resting length as a horse’s head moves up and down while it runs. This stretch of the ligament stores energy, making locomotion more efficient. Measurements on a segment of ligament show a linear stress-versusstrain relationship until the stress approaches 0.80. Smoothed data for the stretch are shown. The volume of the ligament stays the same as it stretches, so the cross-section area decreases as the length increases. Given this, how would a force F versus change in length ΔL curve appear?

Nondestructive evaluation: Nondestructive evaluation (NDE) describes methodsthat quantitatively characterize materials, tissues, and structures by noninvasivemeans such as X-ray computed tomography, ultrasonics, and acoustic emission.Recently, NDE was used to detect defects in steel castings. (JOM, May 2005.)Assume that the probability that NDE detects a “hit” (i.e., predicts a defect in a steelcasting) when, in fact, a defect exists is .97. (This is often called the probability ofdetection.) Also assume that the probability that NDE detects a “hit” when, in fact,no defect exists is .005. (This is called the probability of a false call.) Past experiencehas shown that a defect occurs once in every 100 steel castings. If NDE detects a“hit” for a particular steel casting, what is the probability that an actual defectexists? Step by Step Full procedure required.

A study investigated the effects of cyclic loading and environmental conditions on fatigue crack growth at a constant 22 MPa stress for a particular material. The data from this experiment are shown below (the response is crack growth rate).         Frequency   Environment Air H2O Salt H2O   10 2.29 2.06 1.90 2.47 2.05 1.93 2.48 2.23 1.75 2.12 2.03 2.06           1 2.65 3.20 3.10 2.68 3.18 3.24 2.06 3.96 3.98 2.38 3.64 3.24           0.1 2.24 11.00 9.96 2.71 11.00 10.01 2.81 9.06 9.36 2.08 11.30 10.40   Analyze the data from this experiment (use α = 0.05). Show the ANOVA table.   Analyze the residuals. Show the residual plots.     Repeat the analyses from parts (a) and (b) using ln(y) - natural log as the response. Comment on the results.

Calculate the young’s modulus from one of these two graphs?

Answer the following question: 1. What are the different elements of wreckage distribution in an aircraft accident investigation?

UzNDU3NTYyMjk0/a/MjYOMzAwMjMOOTM5/details Further questions 4.The graphs show how the extension changes with stretching force for four different materials. a. Which two graphs show materials that follow Hooke's law? A B b. Which two graphs show materials that become less stiff as they are stretched? force force D C. Which graph shows a material that maintains the same stiffness throughout? force force 1. A force of 20N stretches a spring by 0.5m. The spring obeys Hooke's law. a. Calculate the spring constant including a suitable unit. b. How much force must a man use to stretch it by 1.5m? 5. A car has a weight of 240OON which is distributed equally over all four wheels. Each wheel has a spring of spring constant 400N/cm. a. Determine the force through the spring on each wheel. b. Calculate the compression of each spring when the car rests on the ground. 6.In a spring experiment the results were as follows: Force (N) Length (mpm 1 2 4 6. 7 50 58 70 74 82 9n 102 125 LELL

1- what materials are included here (z parameter), type of materials considered, property or properties plotted, domain of c, parameter identified 2- what are the vertical and horizontal trends presented 3-what is the take away story from this plot   please answer i will upvote

Viscosity (Pa-s) 400 1016 1014 1012 1010 108 105 104 10² 1 200 800 Borosilicate glass Temperature (°F) 1200 1600 2000 96% silica glass Working range Melting point 400 600 Fused silica 2400 2800 3:200 Strain point Annealing point Softening point Working point Soda-lime glass 1018 1016 1014 1012 1010 108 106 104 10² 800 1000 1200 1400 1600 1800 Temperature (°C) Viscosity (P)

You have been given the following set of data from a soil-geotextile friction test:   Normal stress (kPa) Peak shear strength (kPa) Residual shear strength (kPa) 17 20.2 13 35 31 22 70 52 39.5 140 94 74.5   (a) Plot the Mohr-Coulomb failure envelope (x-axis=normal stress; y-axis=shear stress) (b) Determine the peak friction angle,  and the residual friction angle, . (c) Determine the peak adhesion and the residual adhesion. (d) Calculate the fabric efficiency based on a soil friction angle of  = 35-degrees using the peak friction angle.   **HINT: the equation for efficiency of soil friction angle mobilization is:

You have been given the following test sample data following mechanical testing of 15 test pieces of Silicon Nitride. What is the Weibull modulus of this material? Would you advise the use of a similar material with a Weibull Modulus of 16.3 and a mean failure stress of 485 MPa, if you anticipate that the peak stress on the material could be 430 MPa? Sample 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Select one or more: O a. No O b. 18.6 O C. 13.4 O d. Yes O e. 15.7 f. 17.1 Failure Stress (MPa) 423 459 496 432 447 467 473 499 485 479 505 530 526 490 510 <

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Describe the extent to which your data indicate that mechanical energy is conserved. Consider the percentage differences in the energy changes in Data Table 2 and Data Table 3 in youranswer.

By looking at these graphs, answer the following answer: 1/ Is the material is ductile or brittle? explain by using information from the graphs. 2/ What are the differences between these two graphs?

For the stress-strain curves below, which statements are correct? Stress (MPa) 60 50 40 30 20 10 0 0 A B C. 1 2 3 4 Strain 5 6 7 8 a. The mechanical behavior shown in C is that of an elastomer with low elastic modulus b. While the deformation in polymer A is fully reversible until breakage, polymer B and C only display reversible deformation until 0.1X and 5x elongations respectively The mechanical behavior shown in B is that of an elastomer with low elasticity d. Polymer B and C have an elastic behavior whereas A has a plastic behavior e. The polymer with the necking behavior has the highest strength Of. The polymer with brittle nature is the one that possesses the highest elastic modulus

What is an example of experimental uncertainty?