OENG1189-Assignment 3

Replacing an Existing Structure on Earth with an Optimal Design to Be Constructed on Mars Using Virtual 3D Printing

Due date: 2 Nov 2025

Assessment submission file: PDF file & a CAE file for your best design

Assessment submission types: One online submission for each group

1. Brief introduction of the Project 3

This is a group project which should be completed by group members up to 5 students. Your group is required to conduct a topology optimization to replace an existing building or parts of a structure on earth as a new solution to be constructed on Mars using 3D printing. You will write a project proposal in response to a design call for designing inhabitant structures on Mars colony, i.e., NASA's Centennial Challenges: 3D-Printed Habitat Challenge. Your group should provide the location of this structure and the Google map coordinates.  You may get some idea from the following webpages:

https://www.nasa.gov/prizes-challenges-and-crowdsourcing/centennial-challenges/3d- printed-habitat-challenge/

Figure 1 Building site on Mars and an existing building or structural member on earth to be replaced by the optimal design

A 3D digital model will be provided during your registration of your site/model  selection process. Do site surveying on the 3D digital model, identify a topology similar structure on earth and design the connections between outer shell and internal partition structures to build an FEM with shell element. A description of your site on Mars and the existing building on earth to be replaced should be provided.  You will form. an optimization problem by illustrating the purpose of the optimization design with a figure illustration of its surrounding buildings if they are relevant. The sizes of the structures and designed connections should be provided in your report and the design domain for the  optimization problem should be provided with detailed dimensions. You should make some reasonable assumptions about the requirements for your structure to be optimized, including but not limited to material properties, objective functions, constraints, applied design loads, volume, boundary conditions, construction 3D printer nozzle size limits etc.

It should be noted that your optimal design problem should be different from bridges or reinforcement structure for space station as them in Assignment 1 and 2.

There should be at least 3 components to be considered in your idealised 2D shell FE models, i.e., Part 1 (outer/roof shell), Part 2 (Internal supporting structure) and Connections as Part 3 between those two parts. Usually, the Part 2 is used to support partially the weight of Part 1. If your structure is some components of a big building, the connecting parts to this component should be modelled in the idealised FEMs. The total design load on Part  1 is 100,000N + the last five digits of average student number of all members in your group, you could split this total load into several point loads based on locations from other structures above Part 1(with three components along x, y and z) for better optimal topology.

Figure 2 Site and structure selection

An email confirmation of selection of your structure with the course coordinator is required at your earliest convenience to avoid selection of repeating/similar existing structures on earth.

(1)A photograph of construction site on Mars, (2) an image of similar existing structure on Earth of your choice and (3)a sketch with designed connections and dimensions are required to confirm your selection. First come, first serve.

You must conduct the printability checks for 3D construction printing using CyBe printer for two printing directions using the CyBe Printable Model such as:

•   Printing space check and scale one part of your design to the max sizes that fit into the CyBe printing space if your model does not fit;

•   Printing accurate check to show the layer thickness for two sizes of printing nozzle (0.04 m and P m) and the printing width (0.04m for CyBe Printer) should be the same as diameter the printing nozzle. You will choose an appropriate nozzle size to make your printing check easier.   Note that  the layer thickness is 30% of diameter of printing nozzle (12.5mm for CyBe Printer);

•   Supporting structure check (zigzag or rectangle shape) to avoid possible collapse of outer walls;

•   Inclination check with a limit less than 25 degrees (mark all failed edges and correct at least one edge to illustrate this concept)

•   Curing strength check and adjust printing speed to avoid collapse of the wall under gravity due to lower strength of the fresh material (Determining the printing interval time to increase fresh strength, 0.01% per 5 minutes)

•   Distortion check of the optimal structure under gravity on Mars with fresh material if assembling is used in the construction process

Failing to do those checks will result in losing marks both on accuracy, completeness and professional report. It should be noted that your structures can be scaled down to meet the printing space requirements.

2. Methodology

You are expected to follow optimisation design procedure to do project 3. A flow chart should be provided to illustrate your project with major graphical results as illustration.

Optimisation statements:

Following the procedures above to form an optimisation statement, you are expected to work out the  following mathematical  statements  for  your  optimisation  problem based  on your understanding.

Mathematical expression of the optimisation problem similar to the following one:

f(x) :   Objective function to be minimized - such as compliance,  strain energy, maximum deflection, stress level etc

g(x) :   Inequality constraints (volume, mass, geometric limits)

h(x) :   Equality constraints (material, volume)

x :         Design variables (relative density of each element in the design domain as close to 0

The following information should be provided for each innovative design in the report for project 3

•   Design domain:

(Based on the site of your building. You will provide accurate sizes using FEM model or CAD plots).

•   Objectives:

(Tip: You  should choose a reasonable objective for your  structure preferably, the maximum lateral displacement of the retaining wall)

•   Constraints:

(Tip: You are encouraged to obtain different innovative designs for your selected structure by varying the constraints.)

•   Geometry constraints for connections: (You will idealise the supports the structure or FEM of your site which include the structure to be replaced).

•   Loads

(You will explore the design load of the structure using the idealized FEM with shell element of your choice, the gravity constant on Mars is 3.711 m/s2,self-weight as gravity load in Abaqus of the part 1 should be considered if the other part 2 is to be optimized and vice versa).

Intended construction method and material:

The intended construction method is 3D construction printing with the local materials available on Mars. Two nozzle diameters are used, i.e., 40mm and 1 m.

The construction material for 3D printing is volcanic rock basalt, which is a concrete like material. The average material properties are listed in Table 1.

Table 1. Material Properties for volcanic rock basalt on Mars

The mechanical properties of the fresh material (newly printed) are roughly 0.01% of full strength of fully cured volcanic rock basalt under normal printing speed of 0.5m/s.

More details of the materials available on Mars can be found from the following webpage.

https://geology.com/stories/13/rocks-on-mars/

http://www.psrd.hawaii.edu/May09/Mars.Basaltic.Crust.html https://en.wikipedia.org/wiki/Composition_of_Mars

Intended optimisation and checking tools and their optimization method:

You can use one of or combinations ofthe following tools to design your structure:

•   TOSCA module for topology optimization through RMIT MyDesktop;

•   BESO2D;

The TOSCA uses the SIMP method and BESO2D uses the BESO method, you should revise the optimization statement accordingly if it is applicable.

Intended FEM to check the performance and validity of the different optimal designs:

•   You will build the idealised shell FEM to set up the optimisation design for the outer shell (Part 1) and internal partition structure (Part 2 and connections);

•   You will build the right finite element model (FEM) for one of any optimal topologies obtained (the optimal PS is an easier one) to do all checks as representative part for all of your optimal designs;

•   You will validate your FEM (with simplified geometry and an identical volume to optimal  design)  using   (1)  theory;   (2)  field  test   (a  reasonable  virtual/imaginary experiment is also acceptable) (3) others’ FEMs (One model built by another group member is acceptable);

•   You will replace the initiative design or existing structure with your innovative design to compare different innovative designs;

•   Work out the key performance of your structure and compare the different innovative designs with the initiative design or existing structure with best performance to your knowledge;

•   Check the possible failure of concrete-like material using maximum tensile and compressive strength.

3.  Expected results of the project with 4 new requirements comparing to previous assignments

The general requirements for optimization design and FEA are similar to your previous two assignments. Here is a list of new requirements:

(1). Your structure must include at least three components including Part 1, Part 2 and the connections between them;

(2). You should perform. optimization on both parts and use connections as constraints on geometry;

(3). You need to illustrate the difference between your optimal design model, the CyBe printable model and CyBe printed model (using virtual printer in Robot Studio);

(4). You should conduct printability check for your designs and apply skills to modify your optimal design to pass these checks at least partially;

In your group report, you should consider the following points:

•   Report your FEA procedure and results similar to the report template for Assignment

2 with revision to fit project 3;

•   Evidence to prove the accuracy of your design;

•   You will provide virtual renderings of all your innovative designs in real landscape scenario on Mars;

•   Prepare a STL/OBJ file for 3D printing and check your model with work out the best printing direction and supporting structure required

•   For your video presentation, you will introduce your designs to Elon Musk of SpaceX, or to Mission Team of Nasa and ask them to consider it to be alternative designs for their further inhabitant construction on Mars

For your submission

•   Professional group report (one for each group submitted by group leader)

•   Presentation link for your video presentation on any available online space

•    STL/OBJ for one innovative design with best visual effect

4. Detailed requirements of the project:

In your report, you should provide evidence (Screen shot, table for data input, sketch, charts etc) to show the completion of the following required tasks for Project 3:

Structural Optimization:

1.Optimization Problem ( Optimization statement, design domain, mathematical optimisation statements, objectives and constraints);

2. Method of topology optimization for optimizing two parts separately using concept of cellular structure with EQ material properties;

3. Verification and validation of your optimal designs (Only for recommended design of 1 part in your report);

4. Rendering 3D model ofall parts on Mars site;

5. Conducting printability checks;

6. Provide reasons/merits of those innovative/printable designs to persuade others to use your designs.

FEA modelling information of your best design

1. Geometry modelling of your best design with detailed sizes for both parts and connections;

2. Material model and corresponding parameters for different parts if it is applicable;

3. Loading conditions, boundary conditions and interactions or connection method;

4. Meshing information;

5. FEM verification- (Software report, energy balance, mesh convergence check, following expectations, force equilibrium);

6. FEM validation by comparing with theory, field test (assume one with image example of test) and other’s model.

It should be noted the calibration of Tosca in Abaqus is not required due to long time required for the optimization process using Abaqus on RMIT MyDesktop.

Brief marking rules

The total mark of this assignment 3 is 40marks. There will 5 criteria to mark this assignment.

Criteria 1 - Accuracy. The modelling information, procedures and results are accurate.

Criteria 2 - Completeness.  All required tasks should be completed for this project 3.

Criteria 3 - Professional Report. The report is written in a professional way.

Criteria 4 - Printability checks. Your final optimal design can be printed on Mar using local materials.

Criteria 5 - Video Presentation. You must do the presentation as a group, all members

should be included. Please recommended your design to Elon Musk of SpaceX, or to Mar Exploration Mission Team of Nasa;

This is a group assignment for a group of students up to 5 members. Each group should submit only one report on canvas with a link to your group video presentation and a STL/OBJ file for one innovative design with best visual effect.

To work as a group, you should form a group on Canvas, add a statement of contributions from each member in your final project proposal and do a group presentation involving all members (preferred way for a group project).

More detailed information to earn marks can be found in the detailed marking rubrics as attached at the end of this assignment illustration.

Penalty for late submission of the project:

Late submission of this assignment will incur a penalty of 5% of total mark of this assignment each date after the due date.