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Some analyses require you to record two postures
(initial and final posture) while others use the current posture of the
manikin as a base for the analysis.
As soon as the postures are set and recorded (if necessary) you can
call each guideline individually and apply the analysis. The result of
each analysis will appear at the bottom of the corresponding analysis
window. Each dialog box allows you to specify the criterion required for
that specific task such as duration and frequencies.
Note that all the analyses are real-time based. This means that if you
modify the selected manikin's posture, the current analysis score will
automatically be updated.
Note: You must select one manikin in the scene to be able to conduct
the analysis.
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RULA analysis
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The RULA (Rapid Upper Limb Assessment) system was developed at the
University of Nottingham's Institute for Occupational Ergonomics
(Reference: Lynn McAtamney and E. Nigel Corlett, RULA: A Survey
Method for the Investigation of Work-related Upper Limb Disorders).
It was developed to investigate the exposure of individual workers to
risks associated with work-related upper limb disorders. |
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Lift/Lower
analysis |
In the Lift/Lower Analysis, you can choose between three guidelines: NIOSH 1981, NIOSH 1991, and Snook and Ciriello. These three guidelines
require the use of an initial and a final posture in order to complete
the analysis. A brief description of each guideline follows. |
| NIOSH 1981 |
In 1981, NIOSH (National Institute for Occupational Safety and
Health) published an algebraic equation for analyzing two-handed
symmetrical lifts. The lifting is based on a two-handed symmetrical
lift with no upper body twisting, and the distance between hands is
less than 75 cm (30 inches). This analysis requires a good coupling
between the load and the hands as well as between the shoes and the
floor surface. |
| NIOSH 1991 |
The NIOSH 1991 equation also known as "the revised lifting equation"
deals with two-handed manual lifting tasks. The equation handles a
certain level of asymmetry. This analysis assumes an adequate coupling
between the shoes and the floor surface. |
| Snook and Ciriello |
The Snook and Ciriello lifting and lowering analysis tool is based
on a study done by S. Snook and V. Ciriello. As with the NIOSH
equations, this analysis is based on two input postures. The lifting is
based on a two-handed symmetrical lift. The action (lifting or
lowering) is determined by the displacement of the load in the scene.
There are three levels of lifting and lowering with approximately 30
inches between each.
- from floor to knuckle height
- from knuckle height to shoulder height
- from shoulder height to arm reach
- The horizontal distance is calculated from the chest to the
mid-part of the hand grasp.
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Push/Pull
analysis |
The Snook and Ciriello pushing/pulling analysis tool is based on a
study done by S. Snook and V. Ciriello at Liberty Mutual Insurance
Company. This analysis allows you to compare actual data for a
"pushing/pulling" task to what is considered as a safe force to perform
that task. There are 3 steps defined for the vertical height of hands for the
pushing task:
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from floor to 25 inches
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from floor to 35 inches
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from floor to 53 inches
There are six predefined distances for push:
- 7, 25, 50, 100, 150, and 200 foot push
The gender as well as the vertical height of hands are extracted from
the selected manikin in the scene.
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Carry analysis |
The Snook and Ciriello carrying analysis tool is based on a study done
by S. Snook and V. Ciriello at Liberty Mutual Insurance Company. This
analysis allows you to compare actual data for a carrying task to what is
considered as a maximum acceptable weight of carry to perform that task. This analysis considers two vertical height
distances of hands for the carrying task:
-
For males: from floor to 31 inches, from
floor to 44 inches
-
For females: from floor to 28 inches, from
floor to 41 inches
The manikin gender as well as the distance value for the hands are
extracted from the selected manikin in the scene.
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Biomechanics Single
Action analysis
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This ergonomic tool measures biomechanical data on a
worker in a given pose. From the current manikin posture, the
Biomechanics Single Action
Analysis tool calculates and outputs information such as the lumbar spinal
loads (abdominal force, abdominal pressure, body movements) and the forces
and moments on manikin joints. All the output incorporated in the model are
based on research results and algorithms published by the scientific
community. The forces (loads) acting on the manikin's hands are taken
into account in the biomechanical analysis; these forces represent the load
of carry, push, lift/lower, or pull, depending on the scenario, and are
available for the hands only. Both the Load Properties and the
Biomechanics Single Action Analysis dialog boxes can be open at
the same time. The last analysis is updated when the load is modified. |
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