Widener University BME303 Biomedical Engineering Lab Report

Widener University BME303 Biomedical Engineering Lab Report ORDER NOW FOR CUSTOMIZED AND ORIGINAL ESSAY PAPERS ON Widener University BME303 Biomedical Engineering Lab Report Please submit your lab reports here. The grading breakdown will be as follows: Widener University BME303 Biomedical Engineering Lab Report 1. Cover page (5 points) 2. Introduction (5 points): Brief introduction / overview of the lab with objectives and hypothesis. 2. Methods (10 points): Provide enough detail such that another student could repeat your experiment after reading your report. This section should also include equations used to calculate relevant values (if any). 3. Results (10 points): This section should include any charts, figures, or tables that you create using your data (within reason). Excess plots and tables can be placed in the appendix. Remember that graphics need to be explained in the text before appearing in the report. 4. Conclusions (10 points): What does the data suggest? How does this address your hypotheses? What (if any) were the limitations of the lab? What are your conclusions? I will attached all the fails that you need and also a pic of how you should writ the report,make sure you have to make thre graphs try your best plese attachment_1 attachment_2 1A 1B 1C 2A 2B 2C 3A 3B 3C Diameter( Length(m diameter mm) m) (in) 29.22 40.33 1.150263 30.76 40.33 1.211024 29.67 40.35 1.16798 29.4 39.44 1.15735 30.02 40.22 1.182022 30.37 39.69 1.195539 29.56 40.12 1.163911 29.82 39.81 1.173885 29.77 39.75 1.172179 length (in) 1.587927 1.587927 1.588715 1.552757 1.583597 1.562599 1.579397 1.567192 1.565093 BME 303 Evaluation of a Biomechanical Testing Surrogate for Human Bone OVERVIEW Biomechanical testing, can be performed on medical devices, biological tissue (human or animal), or tissue-surrogates and is used to characterize the material properties of biological tissue, evaluate how different medical devices interact mechanically with biological tissue, and compare medical device designs versus a standard. If you want to work for a medical device firm or invent new implants as a wiz-kid medical doctor, it’s good to be familiar with this type of testing. In this lab, you are going to perform benchtop compression tests on different polyurethane foams that are advertised to behave mechanically like human bone. Because human tissue is (a) expensive and (b) variable in terms of its material properties across individuals (or even within an individual!), it is sometimes advantageous to use these types of “surrogates” for biomechanical testing. For instance, if you are testing the compressive strength of a new orthopaedic device that is screwed into trabecular bone, you might choose to use a bone surrogate so you could (a) run more samples (because it’s cheaper), and (b) get a cleaner reading on the performance of your device because you’ve eliminated the testing “noise” due to the variability in the tissue samples. Your job in this lab is to determine whether the commercial polyurethane foam is a valid test surrogate for human trabecular bone in terms of its compressive strength and modulus. The foam is available in different densities, and you must first determine whether the mechanical properties vary by density. Because trabecular bone is extremely heterogeneous – varying by anatomic site within each donor and also by bone density of the donor – you must then construct a scientific argument as to the anatomic site and donor bone density (osteoporotic, osteopenic, or normal) that best matches each foam density. Page 1 SECTION I: The point of Section I is to get you thinking about the design of your experiment and become familiar with some of the scientific literature. 1. Experimental Design: a. You’re running compressive tests on 3 different densities of commercially available polyurethane foam. b. You will be given a roughly 9 cm x 13 cm wide by 4 cm thick sheet of each density of foam. Test specimen height should be 4 cm, and the diameter is 30 mm. c. You will test 3-4 specimens per group for a total of 9-12 tests/team. d. Load rate will be 1 in/min. Make sure to write it down because it’s an important component of experimental design. e. You will be recording compressive force and displacement during the test; but the outcome measures will be compressive strength (in MPa) and modulus (in GPa). Know what those outcome measures mean and how to calculate them from a force-displacement curve. 2. Reading the Literature: Go to Pubmed (www.pubmed.org) and read the following journal articles that involved compression testing of human bone. Take notes, and be prepared to discuss how your experimental design compares to theirs. Kopperdahl DL et al. Yield strain behavior of trabecular bone. J Biomech, 31, 601-608, 1998. Morgan EF et al. Dependence of yield strain of human trabecular bone on anatomic site. J Biomech. 34, 569-577, 2001. Widener University BME303 Biomedical Engineering Lab Report 3. Record Keeping: You should be storing your notes and data in your general lab notebook for the course and a master spreadsheet specific to this experiment. a. Lab Notebook: Thus far for this experiment, your lab notebook should contain notes from your reading of the literature. During the experiment, you’ll want to take notes of things like specimen geometry, deviations from the test protocol, observations of failure patterns, etc. b. Master Spreadsheet: You may want to create a Master Spreadsheet for this experiment as a team at this point. Think about how you’ll want your data to be organized once you start running tests. Page 2 SECTION II: In-Lab 4. Specimen Preparation You’re going to have to make your own test specimens for this lab. You’ll have a limited supply of material, so use it wisely. a. You’ll receive your foam blocks. b. Measure and record the length, width and depth of each block three times and average the results (these measurements will be used in the stress and strain calculations). c. Create an ID system for your samples and label them. 5. Biomechanical Testing You’ll be running the compression tests on a uniaxial load frame (meaning it can load in tension or compression). It’s been outfitted with compression platens that are mounted to a load cell, which records the applied force. An instructor will orient you to all of the controls on the system, but you will need to do the bulk of the work yourself. a. Check the set-up of the load frame i. Test the functionality of the load cell by applying standard loads of various increments. Record this verification in your notebook (very important). b. Check and record displacement rate (1 in/min). c. Run a preliminary test specimen and download the results to your laptop. Check that the data look okay, meaning the sampling frequency is set properly and you’re getting the output data that you expected. Repeat preliminary testing until you’re satisfied that your test protocol is working properly. d. Take pictures of your lab set-up e. Test all of your specimens i. It is generally good practice to randomize the order of testing across test group. For example, you might test one specimen from one group, followed by one from another, etc, until all specimens are completed. Widener University BME303 Biomedical Engineering Lab Report You’d do this to prevent bias from something like your load cell “drifting” out of calibration during your test period. ii. For each test, make sure to record any observations in your notebook. For instance, if the specimen suddenly popped out of the test frame prior to ultimate load, you’d want to have a record that, that happened in order to exclude the specimen from the final data set. Again, your lab notebook is critical. iii. If anything looks extremely wrong during testing – for instance, you’re getting output values that are way out of range – stop the test. Repeat preliminary testing before restarting. Page 3 f. Transfer all raw data files from the lab computer to your laptop prior to leaving the lab. 6. Data Analysis You need to make sense of all of the data that you collected from mechanical testing. When analyzing data and interpreting it, you should always keep in mind your original study objectives. That will help you organize your data in a way that will lend itself to generating graphs. The main goals of this lab are: (1) to measure compressive modulus and strength as a function of foam density; and (2) to determine what these modulus of elasticity compare to in the human skeleton. Here are a few tips for how to tackle the data in this experiment: a. Generate stress-strain curves: For each specimen, convert the axial force vs. displacement data into stress versus strain and generate a plot. Remember that the geometry of each specimen might be slightly different, depending on specimen preparation. b. Determine modulus: To measure modulus, use the methods described in the following article: Morgan EF et al. Nonlinear behavior of trabecular bone at small strains. 2001. Journal of Biomechanical Engineering 123, 1–9. c. Aggregate Data: Calculate averages and standard deviations for each outcome measure (modulus) by foam density. Present this in table form. d. Comparison to human bone: There are several review articles and book chapters that provide excellent tables summarizing (cortical and trabecular) modulus by anatomic site. You may want to use the following table as a starting point in your literature search for trabecular bone mechanical properties as a function of anatomic site and bone density. Page 4 Table 2: Human trabecular bone material properties by anatomic site. Taken from Cowin SC, Bone Mechanics Handbook, Chapter 16, © 2001, CRC Press, LLC Page 5 … attachment_3 attachment_4 Get a 10 % discount on an order above $ 100 Use the following coupon code : NURSING10

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