Virtual Testing of Composite Pressure Vessels

Virtual Testing of Composite Pressure Vessels Virtual Testing of Composite Pressure Vessels Composite pressure vessels generally perform better and last longer than traditional metallic pressure vessels. They are also more corrosion-resistant and can withstand higher pressuresfor example, hydrogen needs to be pressurized to 70 MPa to achieve minimum vehicle autonomy requirementssomething that is difficult to achieve with metal.There are a number of restrictions on size, weight, efficiency, and physical reliability of hydrogen storage devices for the automotive industry. At these smaller dimensions hydrogen needs to be stored at very high pressure in order to be energy efficient, which in turn requires a very strong and fatigue-resistant container, such as a carbon fiber-reinforced composite pressure vessel.Although stronger than metal, carbon-reinforced composites totenstill fail. This usually starts at a microstructural level, such as fiber breaking or matrix cracking. It can also b e related to variances in microstructural design elements, such as fiber orientation and fiber volume fraction, which also have great impact on overall structural performance.Fiber AlignmentIn structures made of composite materies, damage actually starts at a very small scale compared to the size of the structure itself, says Leandro Castro, co-founder of MultiMech Research and Development, a provider of advanced computational tools for evaluating complex engineering challenges. For example, in carbon fiber composites, debonding, another important type of damage in composites, can occur between the fibers and the resin surrounding them, where each carbon fiber is about 0.0050.010 millimeters in diameter.Fiber alignment in the composite material is also important. If fibers are aligned parallel to the load direction, then the overall composite failure is controlled by the failure of the fibers, which have very high strength. If the fibers are aligned perpendicularly to the applied lo ad, then the failure of the composite is dominated by the matrix, as well as the interface between matrix and fiber, which is much weaker than the fiber.Created by MultiMech, MicroMech is the industrys most realistic microstructure reproducer. It is capable of virtually creating a wide range of microstructural types, such as fiber and particulate composites.stellung source Multimechrd.comDesigners and engineers strive to accurately predict the physical reliability of materials and their microstructures before production starts. This requires sophisticated software and algorithms. For example, MultiMech RD provides two-way coupled multi-scale mechanics software that can evaluate events happening at multiple scales simultaneously using multi-scale algorithms for both impact and quasi-static problems, including explicit crack modeling. This sort of approach allows the design team to build virtually any material from the ground up (fibers and resin) and accurately simulate the physical reliability of the designed structure, before the first physical prototype is ever made.This allows engineers to control microstructural design variables, such as fiber orientation, volume fraction, type of fiber and matrix, and assess the effect of each design variable on the overall structural performance of the component by using its unique two-way coupled multi-scale solver, says Flavio Souza, also co-founder of MultiMech RD. The software can generate microstructures automatically to expedite simulation pre-requisites. It can automatically create microstructures of existing or novel materials so engineers have the most freedom of design by virtual testing combined or new materials before they are ever manufactured. In such cases, engineers can get a feeling for the mechanical response of combined resin/fibers and actually design the material to meet their design specifications.Optimizing Design When designing composite pressure vessels engineers must determineThe most appropriat e fiber and resin matrixHow many layers/plies are neededFiber orientation in each layer/plyThe level of damage (microcracks) the composite can withstand.These questions are mostly related to defining parameters to maximize the stiffness, strength, fatigue resistance, and long-term performance of the composite pressure vessel. Due to either service loading or manufacturing defects, virtually all composite structures exhibit microcracks, says Souza. Each microcrack may or may not propagate during service life and new microcracks may be initiated when the composite is subject to thermo-mechanical loading.Predicting failure is extremely complicated from the engineering viewpoint because even though carbon fibers can be considered an elastic material, the surrounding matrix is mostly a thermo-viscoelastic material.While the fibers carry most of the load of carbon fiber composites, loaded in the fiber direction, their long-term behavior and failure arecontrolled by the viscoelastic (time- dependent) properties of the matrix surrounding those fibers, Castro points out. The material will also have intrinsic statistical variations due to manufacturing. Carbon fibers are relatively expensive and can account for most of the cost of a composite pressure vessel, so they need to be used wisely. Our two-way coupled multi-scale mechanics software has capabilities for modeling damage evolution in composites, which is essential when optimizing the design of composite pressure vessels.Mark Crawford is an independent writer.The software can generate microstructures automatically to expedite simulation pre-requisites.Flavio Souza, co-founder, MultiMech R&D

Why the Fight for Paternity Leave Is So Important

Why the Fight for Paternity Leave Is So ImportantWhy the Fight for Paternity Leave Is So ImportantIm Fighting for Paternity Leave - So Should YouFighting gender inequality in the workplace includes letting fathers to be fathers.Earlier this month at Women Deliver, one of the worlds largest conferences on gender equality and womens rights, I was part of a team that made an announcement. The topic paternity leave.To some, that may seem surprising. Why talk about dads at a conference for women? The answer is simple. Supporting men as caregivers is a necessity for gender equality.In the not-too-distant past, businesses were built on a militrischer abschirmdienst Men model. The presumption was that women will stay home and do all the caregiving, while men stay at work. That way of thinking helps explain why the United States still has no national paid maternity leave. The thought process behind it is that the man will make the money, while the woman stays home. (For mora on this, see my opening remarks at a U.N. event.)Unfortunately, the structures that keep those old ways in place, including workplace policies and cultures, still havent been rectified.Today, most businesses have some paid maternity leave, usually covered as disability leave following a birth. But despite some progress in recent years, only 29 percent of U.S. businesses offer paid paternity leave.And while unlike the United States, virtually all other countries offer some paid maternity leave, fewer than half offer any paid paternity leave.It gets worse. Even when paternity leave is available, numerous forces prevent men from being able to use it in its entirety.This brings us to the Women Deliver conference, which took place in Vancouver. Dove Men+Care a company I partner with on this issue and Promundo released the State of the Worlds Fathers report, packed with data from interviews with more than 11,000 men and women. The findings show just how big a problem this is.The overwhelming majority ( 85 percent) of fathers across seven countries want more time at home to care for their new children. But paternity leave often pays only a fraction of what men make at work and after welcoming a new child, families are particularly strapped financially. Forty percent of parents say financial barriers are the biggest impediment to paternity leave.The stigmas against taking it are also powerful. Majorities of women and men say attitudes among colleagues and managers often leave dads feeling unable to take their paternity leave. This is a topic I covered in depth in my book, All In. Men have been fired, demoted, or lost job opportunities for taking paternity leave or requesting a flexible schedule.I explored this in the wake of my own battle for fair parental leave. When my wife was pregnant with our third child, we determined that Id be needed at home for caregiving after the birth. The policies I was under at CNN, part of Time Warner, allowed any parent 10 paid weeks after having a child except a biological father who had his baby the old-fashioned way.I challenged this internally. After our daughter was born prematurely in an emergency and the company refused me the 10 paid weeks, I took legal action. Ultimately, the company revolutionized its policy, in a win-win for parents and for the company itself.Businesses benefit from making paternity leave a reality not just officially in policy, but through a culture of supporting men in taking the leave. Its proven to attract and retain employees and increase gender equality in an organization. After all, as long as men are prevented from caregiving roles, those responsibilities will fall more on the shoulders of women. Theyre pushed to stay home more, while men are pushed to stay at work more, and the sexist cycle continues.To help paternity leave become a norm at businesses everywhere, Dove Men+Care has partnered with Deloitte, Women Deliver and Promundo to create a Paternity Leave Global Task Force. Its aim is to identify and promote solutions that will result in improved access and uptake of paternity leave for all men.Announcing this plan at the conference, Women Deliver President and CEO Katja Iversen called the effort a no brainer. Alan Jope, CEO of Unilever (Dove Men+Cares parent company) said the commitment to paternity leave is so important because everybody wins moms win, dads win, and the kids win.Its time to put the Mad Men era behind us once and for all. For that to happen, businesses must embrace modern fatherhood. Todays dads are as committed to caregiving as moms are. Lets make koranvers they get a chance to be there, from day one.The fight for gender equality affects company culture. Make sure you land a job with the company that shares your values by strengthening your resume. Submit here for a free resume review from TopResume.Editors Note This piece was written by Josh Levs and originally ran on Glassdoor. It is reprinted with permission.Recommended ReadingThe Modern F ather Establishing Work-Life Balance for MenWomen in the Workplace How to Get Past the Glass Ceiling13 Great Companies for New Parents to Work

How to Create Outstanding Keyword Headers for Your Outline Format Federal Resume

How to Create Outstanding Keyword Headers for Your Outline Format Federal ResumeHow to Create Outstanding Keyword Headers for Your Outline Format Federal ResumeHow to Create Outstanding Keyword Headers for Your Outline Format Federal ResumeHere is something we have heard many times from misinformed federal jobseekers and even federal resume writersI still employ the include the kitchen sink approach as I assume that the USAJOBS resumes are still first being read by computers.No, no, no, no, and no.Federal resumes are read by actual people, not computers. Writing your federal resume for a computer and not a philanthropisch will in most cases put you out of the running for the job.Keeping in mind that a human is sorting through hundreds of applications per vacancy announcement,you must make koranvers that your resume clearly states your qualifications for the jobs as effectively as possible. Dont let the reader guess. Make it clearThe absolute best federal resume format to accomplishme nt this goal is the Outline Format with keyword headers. I have already talked about why and how this format works in this blog post Help Me Hire a Minion. Please read it before you proceed, because the rest of this article will build on that foundation. You can also check out a full sample of the Outline Format federal resume here.Done?Now, lets take it up a notch and see what else we can do to with our keyword headers to make sure they really hit the mark.1.Copy the KeywordsThis tip is so easy to do, and so vital. USE THE KEYWORDS from the job announcement if you have that particular skill or knowledge. The keywords are found in the Duties, Specialized Experience and KSA sections of the job announcement. Yes, I give you permission to copy them straight out of the announcement its not plagiarism. Do not make the reader guess whether the words in your federal resume match the words in the job announcement. This is particularly true if you work in a technical field.2. Put Your Best F oot ForwardWrite the most important keywords at the top of your resume or at least on the first page. Even within a job block, try to order the keyword headers from most important to least important.You can tell which keywords are the most important by the order they were listed in the announcement, and how many times each one is repeated in the announcement (including the questionnaire).3. Full CoverageALL of the important keywords from the vacancy announcement and questionnaire must be addressed in your resume if you have the requested skill, knowledge, or ability. Questionnaires clearly state that the reviewer (again, a person, not a computer), will cross check the resume to see that your indicated level of expertise is justified in the resume narrative. Again, dont make them guess make it as clear as possible.4. Now, Really Punch ItOnce you are using keywords properly and clearly in your resume, what else can you do to highlight them? Link your accomplishments to the keyword hea ders to show off your skillsHere is a real accomplishment example. What do you think about this persons qualifications in the area of database and recordkeeping system?Key accomplishmentRevamped an inconsistent and unreliable electronic filing system. Developed and implemented an improved coding system, which has provided more accurate and reliable data access and improved organization of over 400 technology transfer agreements. Corrected numerous inaccuracies in paper and electronic file classifications. Meticulously entered new data in the system to ensure specialists can retrieve, amend, and generate reports.Lets See These Four Points in ActionHere is a current vacancy announcementJob TitleBudget AnalystDepartmentDepartment Of JusticeAgencyOffices, Boards and DivisionsHiring OrganizationBUDGET STAFFJob Announcement NumberBS-15-1311067-MPPSALARY RANGE$52,668.00 to $99,296.00 / Per YearOPEN PERIODSaturday, January 24, 2015 to Saturday, February 7, 2015SERIES GRADEGS-0560-09/12DUTI ESAs a Budget Analyst GS-0560 you willReviewing historical data and estimates for budgets that titelseite large internal operating programs or a functional areaDeveloping specific instructions and procedural guidelines for assigned programs for the preparation and completion of budget estimatesAssisting in review and coordination of accounting documents and apportionments, allocations and operating budgets preparation of budget briefing materials Analyzing expenditures versus commitments to identify and assist in the resolution of problems inherent in the management of resources for the DepartmentReviewing and coordinating documents that reflect budget execution activities.GSs of specialized experience include Reviewing historical data and estimates for budgets that cover large internal operating programs or a functional area, Developing specific instructions and procedural guidelines for assigned programs for the preparation and completion of budget estimates, Resolves difficult p roblems of prediction and forecasting, Identifies expenditures and differences between proposed changes to internal operating programs and projected spending, Assisting in review and coordination of accounting documents and apportionments, allocations and operating budgets.Tip 1 Copy the KeywordsThe easiest way to do this is to make a list of the keywords that you find in the announcement (in bold above). Then simply use these keywords as your headersKEYWORDS / HEADERS FOR YOUR OUTLINE FORMAT FEDERAL RESUMEREVIEW HISTORICAL DATA AND PRODUCE BUDGET ESTIMATESDEVELOP BUDGET INSTRUCTIONS AND GUIDELINESRESOLVE PROBLEMS WITH PREDICTION AND FORECASTINGIDENTIFY EXPENDITURES (and differences between proposed changes)PRODUCE INTERNAL OPERATING BUDGETS AND REPORTSCOORDINATE WITH ACCOUNTING DEPARTMENTSTip 2 Put Your Best Foot ForwardIn the case of the above Budget Analyst position, this phrase is repeated the most BUDGET ESTIMATES. Use this keyword in your resume / job blocks as close to the to p as you can. Use it in as many job blocks as you can.Tip 3Full CoverageMake sure to hit all of the major keywords in our keyword list above. Also, if you click on the link in the announcement that goes to View Occupational Questionnaire, you will find a list of tasks at the end. Go through the list to see if there are other skills and abilities that should be covered in your resume. I see that preparing budget briefing materials actually comes up twice in this list, so shoulddefinitelybe covered in your resume.Tip 4Now, Really Punch ItIn this example, add a couple of accomplishments involving the development budget estimates and explain the challenges involved and the problems that you overcame. Did you have to deal with difficult management? Or an unreasonable deadline? Lack of information? Make sure you spell it out for your reader to understand how amazing your accomplishment is.Common Sense Tip for Your Federal Resume Use keyword headers for a real, human reader.Paulina Chenhas a passion for taking the complex and making it simple for people to understand. Paulina has been a graphic designer, developmental editor, Certified Federal Resume Writer and webmaster for The Resume distribution policy for over 10 years. Since receiving herCertified Federal Job Search Trainercertification, she has been eager to show federal applicants that writing your best possible federal resume is within your reach. If you need more writing help with your federal resume, contact us for an absolutelyfree project review. If you need expert advice or training,Kathryn Troutmanthe Federal Resume Guru is your best bet on the planet.