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Design for Reliability [clear filter]
Wednesday, May 15


Condition Monitoring of a Cycloid Gearbox
A cycloid drive for gearboxes allows for high reduction ratio and zero or very low backlash. The cycloid gear design is based on compression, whereas most gear interactions are based on shear. Further, the contract of a cycloid gearbox is typically rolling vs. sliding, which is seen in traditional gearboxes. These features of a cycloid gearbox allow for high shock load capacity, high torsional stiffness, and quiet operation.

This paper details the modeling required for correct configuration to perform analysis on the cycloid gearbox and then is demonstrated on a 51:1 ratio, run to failure test. This paper documents the sensitivity of standard condition indicators for gear/bearing during the run to failure test.


Eric Bechhoefer

CEO/Chief Engineer, GPMS Inc

Wednesday May 15, 2019 10:30am - 11:00am
Freedom Ballroom II



Rapid Impact Testing of Any Size Structure
One of the limitations of conventional modal testing using a roving impact hammer is that the reference sensor (usually an accelerometer) must remain fixed throughout the test. Since the accelerometer must be connected by a wire to the data acquisition system. a very long wire may be required when testing a large structure. Furthermore, better quality signals are possible if each impact force is applied closer to the response accelerometer. Because it does not require a fixed reference sensor throughout the test, a Rapid Impact Test is faster and easier to use on any size structure.

In this new method, either the impact hammer or the accelerometer can be moved to a different DOF between acquisitions of data. One sensor can be “hopped over” the other in slinky fashion, or both can be moved, provided that a chain of FRFs is calculated from the acquired data. Each FRF has two DOFs associated with it. An FRF chain is formed when each FRF has the same DOF as another FRF.

An FRF chain is a set of multi-reference FRFs. The multi-reference FRFs can be curve fit using single-reference methods, but the resulting modal residues must be further processed to obtain mode shapes.
The residue post-processing is based on the relationship between modal residues and mode shapes.
Examples using an impact hammer, uni-axial accelerometer, and 2-channel data acquisition, and also using an impact hammer, tri-axial accelerometer, and 4-channel data acquisition are included in this paper.


Mark Richardson

President & CEO, Vibrant Technology, Inc.

Wednesday May 15, 2019 1:30pm - 2:00pm
Freedom Ballroom II


Motion Amplification

Jeff Hay

CEO, RDI Technology Inc

Wednesday May 15, 2019 2:00pm - 2:30pm
Freedom Ballroom II


Deliberations on Foundation Design Method for Rotating Machinery
For on-shore applications, the support structure for a rotating machine normally consists of a block foundation. Adequate dynamic analysis of support structures for rotating equipment is necessary to ensure good conditions for the operation of the supported machine and safeguard other machinery near the subject rotating machine, as well.
The normally practiced method tries to achieve an under-tuned support structure which considers the machine mass and block foundation mass as one entity. Calculations consider that unbalance of the rotating machinery train generates a centrifugal force, which depends on the total mass of the set distributed in the two points of the axis, on the eccentricity between the centre of gravity of the rotor and the geometric axis of rotation, and on the angular velocity of the train. The design procedure assumes that the unbalance force is transmitted to the foundation. This paper endeavours to highlight that revised design procedures for support structures of rotating machinery should consider the stiffness ratio of the bearing support (casing) and the rotor - bearing system and restrict to assume that all vibrations are transferred to machinery foundation irrespective to the type of machine. Similarly, in the case of equipment with AMB (active magnetic bearings) very less vibration is transferred to the casing and after foundation as the magnetic flux helps rotor to levitate. This paper takes an approach of rotor dynamics to propose a revised thought process of structural support design.
The second objective of this paper is to propose the foundation be supported by low cost dampers at all sides of foundation block thereby minimising shear waves transmitted to the ground. This proposal should enable a smaller foundation size with less effort on site construction.



Manager Mechanical - Rotating Equipment, PETROFAC INTL. LTD

Wednesday May 15, 2019 2:30pm - 3:00pm
Freedom Ballroom II


Devices for in Situ Tuning of Machinery Structures to Mitigate Resonance.
The amplitude of machinery vibrations becomes very high when any of a support structure resonance frequency lies within the regime of machinery operating frequency. During resonant condition, the support structure normally demonstrates vibrations in rigid body modes and aggravating the shaft vibration conditions.
Sometimes, the evaluation of resonant frequencies for equipment base frame is not given its due importance by the OEM. For medium sized rotating machines. To identify such condition at site and rectification is cumbersome.
Tuning of the base frame can be done either by increasing mass m or increasing k by stiffing the base frame to shift its resonant frequency. A passive and active control of coupled modes of vibration (rocking and pitching) can be controlled by using servo valves and hydraulics. For passive control, some devices can used which can mitigate the structural resonance problem. The proposed methods shall cover any possible discrepancy of structural resonance and on-site grouting issues where a support structure may undergo push pull action by above lacunae thereby aggravating machinery vibration



Manager Mechanical - Rotating Equipment, PETROFAC INTL. LTD

Wednesday May 15, 2019 3:30pm - 4:00pm
Freedom Ballroom II


Defining and Determining the Appropriate Dynamic Analysis for Rotodynamic Pumps - ANSI/HI 9.6.8 Guideline
avatar for Peter Gaydon

Peter Gaydon

Technical Director, Hydraulic Institute
Peter Gaydon is the Director of Technical Affairs at the Hydraulic Institute. Mr. Gaydon held design, development, and test engineering positions with major pump manufacturers prior to joining the Hydraulic Institute. With the Hydraulic Institute, Mr. Gaydon has technical responsibility... Read More →

Wednesday May 15, 2019 4:00pm - 4:30pm
Freedom Ballroom II


Towards Replacement of Failed Parts on the Battlefield via Casting Metals in 3D-Printed Desert Sand Molds
Additive Manufacturing has changed the face of conventional metal forming technologies. Conventional metal casting involves the manufacture of solid forms or patterns that sand is formed around to develop the shape of the cavity that is filled with liquid metal. The patterns or tooling for castings will often cost as much as 100 times that of the needed casting and require weeks to months to produce. The tools must then be stored, maintained and repaired between uses. Because of the amount of space required and the length of time required for producing patterns, the technology is not conducive to a mobile manufacturing platform. Additive Manufacturing (AM) and digital part creation has allowed the production of castings within days rather than within weeks or months. It has eliminated the need for the lengthy production of costly tooling with requirements for storage space. With the proper tools and training additive manufacturing for metal casting will allow replacement of critical cast components and provide for weapon system sustainability on or near the battlefield. The objective of this project is to show a proof-of-concept of in-theater production of replacement parts for long lead time DoD critical components utilizing a sand 3D-printer with actual desert sand to produce sand molds from a CAD drawing of the actual part, followed by pouring molten aluminum into the casting molds. The parts will subsequently be produced by optimizing the casting mold design, with appropriate gates and risers to allow for successful casting.

avatar for Marc Pepi

Marc Pepi

Materials Engineer, US Army Research Laboratory

Wednesday May 15, 2019 4:30pm - 5:00pm
Freedom Ballroom II