# Biomechanics ( Ergonomics )

Identify the purpose of each analysis and explain the results collected as they relate to the context of the situation (qualitative description). If changes are needed, based on your findings, make recommendations for redesigning the task such that the physical demands will be substantially decreased (and hopefully to acceptable levels). Justify all recommendations. In addition to these general components, which should be included in the report, your supervisor has specifically asked you to include the following analyses, and address the following points:

1) Provide a rationale for why ergonomics is important to the success of package handlers and how it can contribute to the bottom line for the company. The point of this section is to make your case to management as to why they should invest in ergonomics analyses and designs (e.g., why is ergonomics important in a work environment, how does it help the workers in a manufacturing plant).

2) Create a free body diagram to illustrate the position of the individual at the beginning of the lift using a stick figure. Include all forces and moments. You can either use a graphing package or a clear hand drawing.

3) Using the information provided above, determine the segment mass and the center-of- mass locations of the following: upper arm, lower arm and torso. Illustrate the COM locations on your stick figure from part 2).

4) Determine, at the beginning of the lift, the static external moments in Nm acting at the elbow, shoulder and at the L5/S1 disc (assume the latter is in the same location as the hip). Note: since you can assume symmetry, you need only present the results for one shoulder and elbow but realize that both arms contribute to the loads acting on the torso/hip. You can ignore the moment acting at the wrist as well as the mass of the hand.

5) Assume that female torso strengths (moments) have the following distributions (mean [standard deviation]): Flexion — 75 [70] Nm; Extension — 180 [155] Nm. The corresponding numbers for males are 143 [60] and 240 [210]. Given the external moment calculated in part 4), what percent of females and males have sufficient torso strength to perform this task? Note that only one distribution is relevant (either flexion or extension), though you must decide which is appropriate to use based on the demands placed on the worker (points will be deducted if you present both).

6) What is the total low back muscle force (FM) required to maintain the static posture at the initial point in the lift? What are the compression and shear forces acting on the spine (at L5/S1)? Is this task safe with respect to the loads on the low back? (Assume the moment arm for the back muscles is 6 cm.)

7) What package mass will produce shear forces below the ‘Action Limit’ recommended by NIOSH? (Note: the action limit is FS < 500 N)

8) After considered full body segment angles in a 3D static biomechanical model (see Figure 5), the compression force at L5/S1 shows 7125N. Based on this model, what are two design changes you would offer to reduce the risk of injury for workers? Justify how each suggestion would reduce risks. You must develop a new model by using the 3DSSPP program to support your design changes.

Compétences : Ingénierie, Génie Industriel

Concernant l'employeur :
( 17 commentaires ) Columbia, United States

Nº du projet : #18033255