P16006: Tub Lift 2

Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

During the detailed design phase, our team sought to finalize our design drawings, bill of materials, engineering analysis and test plants. Furthermore, we seek to draft up a MSDII project schedule. All of these tasks were completed in full, with a few remaining uncertainties regarding the hosing and faucet connections. We were unable to get into contact with our customer to schedule a time to be able to look at her current unit and bathroom once again to make a clear determination. This will need to be addressed in the beginning of MSDII to see whether reusing her current hosing is feasible.

Concept Simulation

The following simulation displays the overall premise behind the upwards and downwards movement of the lift using a 3-linkage system.


Piston Analysis

In a typical cylindrical piston, the parameters for consideration are the bore size as well as the stroke length. The bore corresponds to the piston's diameter, while the stroke length pertains to how far the piston can extend. For clarity, these concepts are depicted below.





To download the piston analysis file, please click the following:

Piston Analysis

ANSYS Stress Analysis

An ANSYS stress analysis was conducted in order to evaluate the impact of the forces on the lift on its structural integrity. The visual depictions can be seen below. As you can see from the graphics we're experiencing max stress at the pin connections beneath the chair plate which is expected. Originally the chair plate was going to be made of aluminum, similar to the gross majority of the structure, but the system failed in the back corners causing it to become warped and drastically deformed inwards at the center. Therefore we opted to simulate the system with a stronger material for the chair plate, steel. With a steel plate the max stress experienced at the bolts are 71428 psi, and the ultimate yield of steel is 84800 leaving us with a FOS of 1.2.



To download the ANSYS stress analysis file, please click the following:

ANSYS Stress Analysis

Euler's Buckling Analysis

The Euler analysis is intended to assess the allowable load on the lift such that it does not succumb to buckling. Given the output below, it has been determined that the lift assembly can withstand the applied forces without any buckling.


Drawings, Schematics, Flow Charts, Simulations

Main Lift Assembly

The following pictures display the main lift assembly in an isometric view. The main lift is responsible for transporting the customer up and down within the tub. Note that it has a manual swiveling functionality, which can be combined with a swivel assist assembly if desired.


To view or download the relevant design drawings, please click the following:


To download the relevant CAD files, please click the following:

Main Lift Assembly

Swivel Assist Assembly

The swivel assist assembly is a separate entity whose purpose is to assist the user with the rotation of the tub lift seat (such that it does not have to be manual). It clamps onto the side of the bathtub and is powered via battery. The assembly attaches itself at a point on the tub lift via a drop pin.



To view or download the relevant design drawings, please click the following:


To download the relevant CAD files, please click the following:

Swivel Assist CAD

Full Setup

The following images display the full setup of the main lift with swivel assist inside a model of the customer's bathtub.



To download the relevant CAD files, please click the following:

Tub Assembly

Bill of Material (BOM)




To download the finalized Bill of Materials, please click the following:

Bill of Materials

Test Plans

The following chart displays the desired test plants that will be implemented. These test plans address the various engineering requirements identified during the earlier phases of the design process.


To download the finalized test plants file, click the following:

Finalized Test Plans

Risk Assessment


Please click the following link to download:

Risk management Assessment

Plans for MSDII

The following displays the draft project plan for MSDII. In addition to this we will need to verify a meeting time with the customer to determine if we can utilize their current tub lift hosing and faucet connectors.


To download the Microsoft project file, please click the following:

MSDII Schedule Draft

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