2020/2021 Mechanical Engineering Industry-Sponsored Student Capstone Projects

adidas is a global company rooted in sport with a primary focus in scalable 3D printed footwear. adidas strives to understand the relationship between mechanical and material properties and experiential and emotive metrics in 3D printed, lattice-based footwear components. The students worked to form the foundation of “Sensory Standards,” a library that helps to identify the relationship between the mechanical and materials properties of a footwear component and the emotive response it inspires.

Boeing is interested in assessing the suitability of lattice structures to replace traditionally machined fittings for use in primary structures (fixed leading and trailing edge fittings). The student team worked to create a titanium structural fitting using structural optimization and lattice structures to replace a traditionally manufactured fitting. The team characterized 3D-printed titanium behavior and design, and analyzed and tested creative lattice-type and hybrid geometries to optimize performance.

Boeing Product Development needs a solution for the trimming of a green stringer charge. The stringer is in the cross-section of a T with the blade (aka web) pointing up. The forming operation leaves excess on both the base flange and the blade of the T which must be net-trimmed prior to the next operation. The student team designed a method to stabilize the flexible blade during the trimming operation in order to ensure a high-quality cut and high rate capability. The team also did a failure modes analysis for the design.

The student team worked with Boeing Product Development to explore a linear flow line for handling long, narrow beams that are positioned along the length of an airplane wing or fuselage (called stringers). Carbon fiber pre-preg material is laid up, trimmed, rotated, and transported on a universal handling tool (pallet) that provides indexing to each process cell. The team created a design for the pallet and indexing system, built a prototype that can accommodate material up to 6”x24’’, and demonstrated the ability of the handling tool to automatically connect to a vacuum system and secure and release carbon fiber material of a variety of sizes.

Recent advances in titanium powder bed fusion technology offer attractive aerospace design solutions. However, to offer additive parts as competitive alternatives to traditional casting and machined parts, materials and processes resulting in performance variations must be well understood for wider commercial usage. Research and development is needed to understand the influence of key process parameters on material properties. From Phase 1 study conducted by a capstone team last year, students performed in-depth literature research on powder recyclability and effects on performance. In Phase 2 this year, the new student team focused on understanding performance variations resulting from different material supply (same grade of the material but different powder fabrication method and different vendors). The student team built multiple sets of tension coupons from various titanium material suppliers and performed characterization and static testing. They characterized metal properties with respect to the material supply, the processing variations caused by the differences in supply, and root causes for variations in properties. Results will drive recommendations for material supply and process control parameters that optimize performance/quality.

The student team investigated the static properties of thermoplastic chopped carbon fiber composites and predicted how these properties change with variations in the orientations of the fibers. The results of this project give early information to Boeing to help streamline design processes for complex parts. With this data, Boeing can more effectively map out the alignment of complex carbon fiber parts to handle the unique stress conditions of these parts, and ultimately eliminate the need to test individual parts. Additionally, utilizing thermoplastic carbon fiber parts gives Boeing more opportunities for diverse, lightweight, and strong materials to manufacture quality airplanes.

Two years ago an interdisciplinary capstone team designed and built a three foot symmetric wing, then tested the wing in the UW low-speed wind tunnel. Last year a ME capstone team designed, but did not build, a 3ft asymmetric wing for use on a Formula SAE car. This team did extensive research on feasible welding techniques to join thermoplastic (TP) composite internal structure with TP composite skin. Building on the past two years of work, this year’s student team developed a feasible welding technique that the students can implement and characterize the strength of the weld. The results will contribute to building a welded thermoplastic wing for a Formula SAE car in the future.

The student team worked to establish a process for topology optimization (TopOp) and 3D printing of the upright and other parts of an electric formula-style car for the UW Formula Society of Automotive Engineers (FSAE). The upright rigidly transfers loads from the tires and brake calipers to the chassis. A design for the upright was finalized by a capstone team last year that achieved a 24% weight reduction, and a 300% increase in stiffness. This year’s team printed and processed the final design, validated loads, boundary conditions and material properties, and conducted testing to correlate finite element modeling (FEM) results.

Rod springs are widely used in aircraft door mechanisms to secure component and mechanism positions. Conventional manufacturing technologies use a spring and guiding mechanism, assembled in three parts. Last year a student capstone team demonstrated that it is possible to design a spring rod in one single element (without assembly) using 3D printing. This year’s student team manufactured, tested, and iterated the design, validated against FEA analysis, and developed a parametric design tool to aid in the design of family of similar springs. The testing covered compression testing, stiffness characterization, fatigue, humidity effects, and the effects of internal friction, hysteresis, and strain relaxation.

Spherical bearings are used in mechanical design to address misalignment. These bearings are costly for a small component and have a complicated assembly process. Replacing a spherical bearing with a plain bearing means the capability to self-align is lost resulting in a poor contact distribution in the bearing (i.e., line or point contact). The student team designed a one piece bearing that is additive manufactured and has a contact surface that can accommodate the required loads under misalignments of up to 3° while still providing the required radial positioning. The team tested strength, bending, stiffness, and friction.

By some estimates, building operations and construction account for more than 50% of the carbon footprint of the United States. For decades, great attention has been placed on reduced energy use in buildings. However, in the last few years, awareness has grown that the carbon created in the construction of buildings (known as embodied carbon) is of critical importance. The Carbon Leadership Forum at UW has been a center of thought leadership in reinventing buildings structures and systems to have substantially lower embodied carbon. Mechanical, electrical, and plumbing (MEP) components of new construction buildings can result up to 10-15% of the total embodied carbon of a building design. The student team set out to find ways to reduce the carbon footprint of building MEP systems.

Chronic illness, defined as any disease that requires at least one year of ongoing medical attention, affects half of all American adults and at least 7% of American children, and is particularly devastating in underserved communities in the US where they are contracted at a higher rate than the national average. The economic burden of chronic illness, such as diabetes, obesity, and cardiovascular disease, in the US is unprecedented. Chronic illness also imposes great psychological distress and reduces quality of life for diagnosed individuals and their loved ones. There is growing evidence showing positive outcomes in self-management of chronic diseases with behavioral interventions. However, many of these solutions require active monitoring and burden the patient and caregiver with the need for constant monitoring. The student team tackled the needs of young Type 1 Diabetes (T1D) patients to help manage and monitor symptoms to reduce daily stress and burden associated with T1D. Beta Watch is a medical storage accessory that can attached to a mobile phone and safely and discretely houses all daily essentials of T1D care. Paired with an educational, T1D tracking mobile application, Beta Watch helps T1D patients manage the burdens associated with the chronic illness.

Hypertension and diabetes mellitus are both common conditions that have a high prevalence of co-existence, and are also highly associated with obesity. These conditions are considered risk factors for many diseases, including coronary artery disease, cerebrovascular disease, renal failure, and congestive heart failure, so treatment of these conditions is essential. Monitoring blood pressure is a key factor in managing the co-existence of these conditions. Blood pressure is currently measured using inflatable sphygmomanometer; however these measurements need to be made by a health care worker or at home using an automated tool. Blood pressure can vary greatly over time due to various influences such as diet, stress, body position, temperature, and a wide variety of other factors. For this reason, it is difficult to obtain an accurate baseline blood pressure reading and understand how various interventions and lifestyle choices impact blood pressure. The student team worked to develop a method for unobtrusively measuring blood pressure several times a day to provide accurate information to clinicians and researchers aiming to reduce the hypertension and improve outcomes for chronic illnesses.

To accurately model the dynamics of a tractor semi-trailer, it is important to accurately model joint stiffness within the chassis and attached components. There are several ways in which joints can be modeled in simulation, but it is difficult to say which is most correct for stiffness without physical testing. The student team planned and conducted physical tests of some typical joints found in a tractor chassis to measure their stiffness, created finite element models to replicate the tests, and compared simulation and test results to determine the most accurate way to model the joints. They ultimately analyzed test results to choose the best joint model(s).

Residual stress can lead to premature failure and reduced durability of bonded joints. Most test methods for predicting long-term performance of bonded joints decouple aging and environmental conditioning from constant- or cyclic stresses. Other test methods that apply stress during environmental conditioning do not record stress during tests and are susceptible to changes in stress as the fixture and load-train thermally expand and contract. The student team worked to develop a test fixture capable of applying, measuring, and adjusting stress in bonded joints during exposures simulating thermal-shock, high-temperature processing, and environmental aging.

The TE Connectivity Automation Manufacturing Technology (AMT) team is looking for innovative designs for a rotary insertion machine. An insertion machine is used to insert metal contacts into a plastic housing to form a connector part. Most insertion machines today have horizontal or vertical motions, which involves a change in direction after every insertion. A rotary insertion machine would not have to change directions, increasing the speed of the process. This rotary design would enable potentially higher speeds of the insertion process than what is achievable through linear motions. The student team designed prototypes, analyzed them using simulations, and created a final design model in CAD of the rotary insertion machine.

Whooshh Innovations, Inc. designs novel approaches to transport fish over natural and man-made barriers. Whooshh has successfully used a portable, modular flume fishway that mimics a highly turbulent stream channel with three sections that, when linked, entices salmon and other strong swimmers to swim up an elevation of 4-6 feet and places them at the entrance of the fish passage system. The student team worked to design a new portable, modular flume fishway that is passable by fish with differing swim behaviors and abilities (non-jumping, weak swimmer), to expand the use and application of Whooshh’s technology. The team analyzed several possible designs using 2D and 3D computational fluid dynamics and studied the effects of several design parameters on the flow conditions. They also analyzed the manufacturability of the designs and tested flow conditions with a scaled model.