Structural & Stress Analysis

Structural analysis is critical because it can determine cause and predict failure – evaluating whether or not a specific structural design will be able to withstand the external and internal stresses and forces expected for the design.

Dayton T. Brown, Inc. has a proven track record in structural analysis, testing, and simulation. In many structural tests, subjects are strain gaged and calibrated. This data is collected during complete structural and/or component testing, including during simplified tensile strength tests.

Structural analysis is then performed and, in some cases, correlated with the testing output data. This tactic produces an electronic virtual working model for future design development.

Structural & Stress Analysis Services

img-description img-description Analysis Capabilities

Analysis Capabilities

DTB’s complete structural analysis capabilities include linear and non-linear analyses of structural components and systems under static, dynamic, and thermal loads. DTB has the ability to develop engineering solutions through analytical calculations and the subsequent preparation of technical reports with strength and stiffness analysis; margin of design safety of engineering test articles; structures and components; and the validation of design vs. actual Shear, Moments, and Torsion requirements.

We can also develop load paths and determine buckling loads, limit/ultimate loads, or creep on parts at room temperature or elevated temperatures. Load cells are used to apply forces to components under simulated operating conditions, and the results are used to validate designs and other analyses.

Loading history is recorded through the use of strain gages, load calibrations, data recording equipment, and other instrumentation. Through the use of statistical methods, a loading spectrum can be determined, which expands the recorded data into a full range of conditions. This information can be used in analytical life predictions and for discrete tests.

DTB can also provide structural analysis services for the evaluation and condition assessment of existing structures, including the application of non-destructive, on-site, and load testing methods, for measuring existing states of stress, material properties, structural behavior characteristics, and material uniformity.

img-description img-description Stress Analysis Services

Stress Analysis Services

DTB can design, verify, or diagnose structural issues and design a repair for your product. We have performed successful stress analyses on aerospace components and aircraft modifications by using both finite element stress analysis and classical hand analysis.

We have also performed stress analyses in order to predict the fatigue life and damage tolerance of existing and redesigned arresting gear truss assemblies for carrier aircraft. The purpose of this stress analysis program was to extend the life of the existing arresting gear through analyzing and testing the gear to realistic loads. We developed a realistic loading spectrum based on flight test data for both the analysis and the test. By using strain life fatigue prediction methods, we predicted the fatigue life and damage tolerance of the assembly.

Our experts have also conducted structural analyses of electrical equipment for seismic requirements using the latest building code seismic requirements. We can help you with static, strength, fatigue life, and damage tolerance calculations. Our team of stress analysts can prepare strength certification reports for your product.

Finite Element Stress Analysis and Classical Hand Analysis Capabilities:

  • A free body diagram of the item showing all applied loads and reactions
  • Calculation of the magnitude of the reactions based on static equilibrium or the use of redundant structural analysis methods, such as finite element analysis (FEA)
  • Calculation of the internal stresses using section cuts through the item or the use of FEA
  • Calculation of the allowable stresses based on all possible failure modes, such as material yield stress, material ultimate stress, material fatigue allowable (based on the load spectrum), and the buckling or crippling stress allowable (for compressive loads)
img-description img-description Design Simulation &
Finite Element Analysis (FEA)

Design Simulation & Finite Element Analysis (FEA)

DTB has extensive experience in finite element modeling (FEM) for all types of structures, including static, dynamic, modal, and random vibration (PSD) analyses. These analyses are often used for comparison to strain gage measurements during structural tests. DTB can use your solid models, .dwg files, or paper drawings to create FEM.

We have experience with variable contact, non-linear materials, and non-linear analytical ultimate strength modeling.

Using (FEA) techniques, our structural engineers can help you reduce development time - while accelerating the design process. Modeling through Autodesk Inventor and FEA using ANSYS, our experienced engineers and structural analysts can verify the findings against empirical test data, simplified models, and classical calculations to ensure accuracy.

We can verify the findings in simulated settings in our extensive test facilities to ensure product compliance. Validation and correlation of the simulation with actual experimental measurements is determined by using the displacements from string pods, as well as the load measurements from load cells.

Additionally, our design team can provide services with regards to conceptual design, 3D solid modeling, assembly modeling, and detailing and drafting for both on-site and off-site development.

FEA Simulation Capabilities:

  • Static analysis – linear and non-linear analysis, failure analysis, component life prediction
  • Dynamic analysis – modal analysis, forced response, random vibration, shock, rotor dynamics
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Damage Tolerance Analysis

DTB has conducted many structural test and analysis programs that involve damage tolerance principles and design. Crack growth coupon tests are used to determine the effects of the loading frequency and environment on crack growth parameters.

We can measure the crack growth rate of arresting gear during life extension tests and then correlate the actual test results to analytical predictions of damage tolerance. This type of hybrid testing and engineering work is a DTB hallmark.

We utilize AFGROW and other software packages for the analysis of structures for crack growth life. In conjunction with our stress analysis programs, we have experience in conducting damage tolerance analyses on aircraft antenna installations and equipment modifications.

img-description img-description Vibration Analysis
for Predictive Maintenance

Vibration Analysis for Predictive Maintenance

Our vibration analysts can determine stress points in your equipment and structures. We can also predict failures and recommend preventive measures and design improvements, as required.

DTB’s finite element analysis (FEA) method is used to model the structural dynamic characteristics of vibrations within a mechanical system – the understanding of which is vital to any root cause failure study involving excessive vibrations. The use of vibration analysis and FEA techniques to evaluate the dynamic characteristics of machines and structures prior to fabrication is also important.

Simulated FEA models are used to approximate stress stiffening effects in rotating mechanical components. The FEA analysis models are used to approximate the natural frequencies and mode shapes of complex structural-mechanical systems. FEA techniques can also model the response of your equipment or structure to dynamic loads. DTB’s vibratory testing facilities can simulate vibration and shock responses from a shaker table on a structural component.

We take pride in our ability to develop models that are only as complex as necessary in order to resolve the problem in a timely manner.

img-description img-description Failure & Fatigue Prediction

Failure & Fatigue Prediction

DTB can analyze your product, develop a loading spectrum, and perform fatigue life predictions using strain life, stress life, or load life methods. The strain information can be derived from test data or from finite element modeling (FEM) predictions. We can also perform field strain gage and load measurements to provide data for these analyses.