Contact DTB and tell us your R&D requirements.
DTB provides a complete line of contract research & development (R&D) services in a broad range of areas. Our staff of multidisciplinary experts and extensive testing and US-based manufacturing facilities provide the perfect environment to efficiently further your enterprise.
Please open the topics below, examples of some of the areas DTB has Investigated by request.
Benchmark Testing and Evaluation, Fatigue Testing at Extreme High Temperature
Over the past 60 years DTB has developed extensive experience in fatigue testing. DTB has tested literally thousands of parts for military and commercial aircraft, tanks, trucks and automobiles. The demand for these services has come from the Army, Navy and Aircraft and Ground Vehicle Manufacturers. Much of this testing has been to qualify parts supplied by alternate source manufacturers, using new manufacturing processes or different materials.
Typically this testing is performed by subjecting previously qualified parts to load cycling or vibration testing. This testing of qualified parts provides a benchmark which is used to evaluate the alternate source parts.
An interesting part of this business has been the combination of fatigue testing and temperature extremes. This testing below has been performed for a major turbine engine manufacturer.
Combined Loads Testing at High Temperature
DTB has run a number of combined loads test programs. These tests were performed on various stator, compressor and turbine blades. These blades were fatigue tested at extreme temperatures from 400 to 1800 degrees F. These tests were conducted using a hydraulic actuator attached to the end of the blade using a clamp ring as shown below. The machines to run these tests were developed here at DTB. These were an improvement over the shaker based system used at the OEM since the test was controlled utilizing the actuators internal LVDT for displacement control.
High Cycle Fatigue Testing at High Temperature
High cycle fatigue (HCF) testing is performed on a vibration shaker. This testing consists of mounting the base of the blade to a vibration plate and carefully tuning in the resonant frequency at the desired mode frequency and raising the amplitude to achieve the required stress levels. Calibration of the strain gages is critical for this test since the high strain levels quickly fatigue the strain gages. The entire test is then controlled based on the blade tip displacement. The HCF test is often required to run at elevated temperatures. This requires suspending the heaters above the shaker and cooling the vibration plate to protect the shaker head as shown.
DTB Remote Monitoring / Data Acquisition services provide remote performance-monitoring services at commercial Distributed Generation and Combined Heat and Power (DG-CHP) sites.
Our efforts include the design, installation and commissioning of data logging system at the site and establishing automated collection, reformatting and transmission of data. Each design is tailored to the individual site.
In addition to continuous sensor monitoring, each installation can be configured to provide automatic alarming and notifications, run-hour tracking and notification for scheduling routine maintenance and computation and tracking of efficiency trends and deviations from expected performance parameters.
DTB has extensive experience in developing controlled laboratory pressure wave and shock pulse tests associated with various types of explosive threats.
While DTB can perform all levels of Mil 901
hammer shock testing, we also have been at the
forefront of developing customized shock pulse
test equipment and techniques to replicate the
increasingly hazardous effects associated with
IEDS and other emerging explosive threats.
DTB’s most recent work has centered around the development of repeatable and tunable laboratory explosive shock pulse testing techniques and equipment.
This capability promises to shorten the product development test cycle to significantly reduce time and expense associated with live ordinance field trials.
Improvement of accuracy, repeatability and range of shock pulse delivery has been made possible by leveraging decades of experience and mathematical modeling associated with a multitude of DOD and NASA programs.
Products benefitting from laboratory shock pulse testing include:
3-D Characterization Of Defects In Epoxy-Matrix Composites
The Situation: Client wanted a technique to detect and quantify fiber defects such as wrinkling and waviness in continuous glass fiber reinforced epoxy matrix composites used in helicopter blades.
The Solution: Use Microfocus Computed Tomography with special beam hardening to detect low-contrast fibers with high fidelity.
Perform 3-D reconstruction to understand fiber defects in all orientations and generate critical orientation serial sections through the volume.
Perform physical serial sectioning and compare the sections to CT data to establish one-to-one correspondence for technique validation and POD estimation.
Repairing Diminishing Aircraft Parts: EA6B Tailpipe Project
Given the ever increasing complexity, development cost and prototype-to-production lead time to produce a new [multi-role joint service] aircraft; government and commercial entities are exploring new ways to extend the life of their aging aircraft and to expand their roles and mission profiles. Many of these aircraft although still mission capable, are several decades old.
As the service lives of these aircraft are extended, the demand on the supply of spare parts to support them increases and many of the OEMs have either ceased production, merged with or been absorbed by larger companies or competitors, or have simply gone out of business. The result is a critical shortage of spare and repair parts to support and sustain the aircraft.
Dayton T. Brown, Inc. has the experience and technical expertise to address government and commercial industry concerns about diminishing aircraft spare and repair parts by providing Research, Reverse Engineering and Prototype development services for out-of production aircraft parts and assemblies.
Seeded Fault Testing for Conditioned Based Maintenance
DTB is fully capable in the equipment health
management area. At the heart of any health
management/condition based maintenance system is
the prognostics framework that generates outputs
alerting detection of an existing fault or the
onset of a fault.
By tying the fault to the types of failures that can occur in the particular piece of equipment through testing to identify a monitored parameter (ie: vibration sensing), and relating the parameter to failure mode identification through algorithm development the system can predict certain things.
It identifies the criticality of the fault to the operation of the equipment, provides a timeframe when the fault is predicted to occur, and a confidence level of the assessment. It isolates the fault to the lowest level possible based on the information received and the algorithms developed. It then outputs quantitative symptoms, or evidence data indicating the fault, plotted over time on a graph.
DTB can design health based systems for a variety of applications and perform “Proof of Concept” programs that will demonstrate the heart of the health concept. It is based on using a particular piece of equipment ( eg: rotary shipboard, utility, rail car, wind, wastewater treatment) and performing what is termed “Seeded Fault Testing”.
A seeded fault test is a test in which a known fault component is operated in a condition similar to field conditions and then performance measurements are acquired through a data acquisition system and fed into the health software for engineering analysis.
The initial baseline tests are performed to establish the vibration profile of an “un faulted” system. Following the baseline test, DTB disassembles the rotary equipment and introduces the seeded faults identified in the field. Each seeded fault will be introduced independently and run on the test bench to characterize the vibration profile.
DTB analyzes all of the data recorded during the baseline and seeded fault testing and develops the algorithms required to be used with the health monitoring diagnostics system and are capable of discerning and identifying the seeded faults which relate to field failures.
Earned Value Management
Earned Value Management (EVM), or Earned Value Project/Performance Management (EVPM) is a program management technique for objectively measuring project performance and progress.
EVM has the ability to combine measurements of:
Earned Value Management can accurately forecast project performance problems, an important component of project management. Popularity of EVM has grown significantly in recent years beyond government contracting, where its importance continues to rise.
The use of EVM to affect plans and controls significantly improves both scope definition as well as the analysis of overall project performance. Research has also shown that the principles of EVM are positive predictors of project success.
A DTB client wanted the capability to predict the degradation of a variety of items in shelf-storage configurations. The client also needed to predict life improvement/degradation with alterations in packaging configurations.
The Solution? Develop a conceptual framework to include the aging of packaging as a well as the contents.
Include in the framework, interaction effects between packaging and contents.
Design and perform accelerated aging protocols.
Perform comprehensive data analysis to develop a capability to predict degradation kinetics coupling Arrhenius and empirical components.
DTB’s client wanted to screen a large number (>100,000) of sealed assemblies to non-destructively determine the chemical composition of a powder mixture enclosed within multiple metallic containers of steel and brass. The accuracy had to be better than 0.25% and the screening had to be performed automatically.
The solution was to develop a screening algorithm that used the concept of a master X-ray image to which all others will be compared and which would eliminate geometric deconvolution requirements and to establish a correlation between the chemical composition and X-ray attenuation while developing methods to acquire highly consistent microfocus X-ray images.
And, on top of that, implement the technology in less than four months.
Shock Sensor Circuit Breaker Development
Dayton T. Brown, Inc. developed a new concept for a Shock Sensitive Circuit Breaker with an ultra-fast circuit interrupter built with commercially available hardware that makes it possible to protect shipboard electronics from the sudden impulse of a percussive shock wave.
Fit into one slot of a Naval Shipboard electronics rack, the interrupter will reliably sense, detect, and actuate redundant relays which disengage electrical power to avoid fires and damage to integrated circuits.
Each unit includes a manual on-off switch
for line power, a network port for field
upgrade of firmware, and an indicator light
for operational status.
Following shutdown triggered by a pressure pulse, the interrupter will inhibit reconnection of power until it receives a man-in-the-loop positive reset, so a human is present at boot up in the possible case where latent damage left any components in an unsafe condition.
The modular architecture of this ultra-fast circuit interrupter also allows future expansion of safety checks, such as over-temperature (fire) or the presence of cabin water (electrocution hazard).
Health Monitoring Equipment Design, Evaluation and Installation
Using our vast experience in dealing with a full range of mechanical, electromechanical, pneumatic and hydraulic driven mechanisms, DTB has the capability of designing and fabricating Health Monitoring Equipment (HME) capable of capturing critical data integral to determining proper performance and lifetime requirements.
DTB’s HME can be used to define equipment usage necessary to help in determining the useful life of the equipment and whether or not the equipment has been subjected to an over usage condition creating unwanted strain on the device.
DTB’s HME can also be designed to define normal operating profiles for equipment. This data can be used to detect deviations from the expected data profile thus identifying a problem area within the equipment operation prior to a possible catastrophic event occurring.
HME can be used for land based, shipboard and aerospace applications. DTB has successfully installed Health Monitoring Equipment to monitor Power Plants and Shipboard equipment.
Cost Reduction / Value Engineering
DTB has the facilities and personnel who are well versed in the concepts and methodologies needed to complete Value Engineering Programs. DTB engineering can provide product enhancement solutions for products that have poor reliability characteristics and/or are overpriced. We can also prove out our engineering solutions using our vast array of testing facilities that includes environmental, dynamic and/or structural/fatigue testing to qualify the item enhancement.
DTB can also provide reverse engineering for products supporting the development of drawing packages necessary for future procurement. These efforts support the qualification of alternate sources for various products. Design flaws are identified and eliminated and in many cases extending the usable lifetime of the item. DTB Engineering and Testing expertise can provide value solutions ultimately saving the customer time and money.
Most electric-powered railway transportation systems do not effectively recover and provide for effective reuse of energy from braking.
Currently the majority of subway and commuter rail vehicles are stopped by using a combination of electrical resistors and brake pads.
These systems do not provide any method to capture or reuse this electrical energy and waste it as dissipated heat.
Dayton T. Brown is investigating the feasibility and application of an on-train regenerative braking and electrical storage system. This system could capture and reuse megawatt-hours (MWh) of wasted braking energy on a daily basis.
Tin Whisker Growth Facility
The surfaces of Lead-free Tin surface finishes (including solders) can – suddenly and unexpectedly – form Tin “whiskers.” Whiskers are long, thin protrusions that can be several hundred to several thousand microns in length and that have the potential to cause short circuits either by contact with the surroundings or by detachment and settling on another location.
Another mechanism of circuit failure or malfunction is through the formation
of tin vapor or plasma – to which whiskers are susceptible due to geometry –
and which can provide conductive, short-circuiting paths. Extremely long
whiskers have been observed periodically – e.g. 18 mm long whiskers were
found in 2006 on the Card Retainers of high-criticality (Criticality of 1/1
and 1/R) Space Shuttle Flight Control Boxes.1
The phenomenon of Tin (Sn) whiskers has been known for over 65 years and was not a serious problem because it was found that the addition of Lead (Pb) suppresses or eliminates whisker formation.
However, the RoHS2 legislation enacted by the European Union on 1 July 2006 restricts the use of Pb in electronic products sold in the EU. This has led many electronic circuit board manufacturers to remove Pb from Pb-Sn plating and solders, leaving essentially pure Sn. While this approach is the most convenient and the least costly Pb-elimination strategy for the majority of board manufacturers,3 it also makes the resulting components susceptible to sudden failures due to Tin whiskers.4,5
The dimensions of the problem (of Tin whiskers) are such that they have also
started to affect high reliability (Hi-Rel) circuits. In theory, the
manufacturers and users Hi-Rel components have asked for – and received –
exemptions from RoHS restrictions on Lead-free solders.
In practice however, the Hi-Rel market is miniscule in comparison with the commercial and thus does not offer a particularly strong incentive to the circuit board manufacturers for maintaining multiple production lines (pure Sn and Sn-Pb, for example).
As a result, a majority of the board manufacturers have not only switched to Pb-free solders, but in many cases have done so without changing the part numbers of the circuit boards. This in itself presents a unique problem for Hi-Rel circuits and adds urgency to resolving and managing the destabilizing influence of Tin whiskers.
Remediation Initiative – High Value Aerospace Gears
A new initiative is proposed to remediate high-value precision aerospace gears that have been removed from service because of surface damage (pitting, scouring etc.) before their design fatigue life has been reached. This initiative will use a unique convergence of proven technologies and test-and-evaluation methods to achieve robust and economical remediation.
Generally, surface damage in precision gears is first detected as surface staining or greying, which is in fact micro-pitting, a form of contact fatigue. Such damage can result in increased vibration, increased operational temperatures, and if continued without corrective measures, macro-spalls and a damage cascade with potentially serious consequences.
1,2,3 First-principals considerations indicate that a successful remediation of these highly critical components must meet six criteria:
As discussed in the next section, we propose to meet these criteria by using a unique combination of methods that comprises of:
DTB has the capability to implement script-based integration paradigm in the context of real world engineering application integration problems. Here at DTB the skilled technical staff use modern instrumentation, like computerized data acquisition, along with mathematical/engineering software, like MathCAD and LabVIEW to create customized efficient interfaces. This simplifies and expands experimental and computational problem-solving ability, including tedious tasks, like data acquisition, interpolation, graphing, etc.
The LabVIEW software, a graphical programming language by National Instruments®, is especially suitable for developing automated instrumentation systems using the PC plug-in data acquisition (DAQ) boards. It may be effectively used for engineering data acquisition, analysis, and presentation.
A typical data acquisition system may consist of transducers, signal conditioning hardware, plug-in boards, and LabVIEW® application software. Examples may include monitoring and controlling complete measurement or process system, etc. The plug-in DAQ board enables computerized measurement and control of real world analog input-signals (AI, like with an oscilloscope) and generation of analog output-signals (AO, like with a function generator), as well as digital input/output (I/O) signals.
The main LabVIEW advantage over the classical text/script based programming is its graphical interface where the user naturally builds a program by connecting (wiring) built-in component icons, i.e. by drawing the program’s algorithm.
Another LabVIEW advantage is for use to build computerized or virtual instrumentation since its input/output interface mimics the real-instrument front-panels. It is also full-fledged programming application that integrates advanced data analysis and presentations. In addition DTB structural engineers can also perform python based scripting in the finite element analysis application ANSYS.
Python brings a rich object model, extensive platform portability, and flexible extension model to the table and is freely available through the open source community. These scripts can be modified and run to extend the functionality and automate repetitive analysis enabling efficient labor intensive application integration. Thus the technology application integration extends our capability and enables us do more and better in less time.
Two Primary Reasons to Study Aging:
Investigation Difficulties - Biggest practical concern/issue is how to correlate the test results to service life as this would require a large number of very expensive, time-consuming tests.
That’s why we took the Building Block Approach
Our client wanted assistance in designing protocols to down-select from a suite of several new alloys. The end application was going to involve severe steel-on-steel (both about HRC 62) contact at high speeds. DTB’s solution was to perform highly controlled coupon level tests incorporating the tracking of thermal and damage profiles. The results yielded results that allowed down-selection on the basis of microstructural analysis of damage and sub-damage zones. We also designed and performed component-level high-fidelity testing with contact severity sensing feedback loops to further enhance selection data.