Advantages And Disadvantages Of Mechanical Joining Engineering Essay

Advantages And Disadvantages Of Mechanical Joining Engineering Essay Mechanical joining is the part method to joint components together, which mechanical joining is accomplished have expanded, the number of joints produced continuous to grow and the performance demands and expectations are becoming greater. The joining process can remain the prolific, pervasive, and important of joining process. There has two type of this process such as mechanical fastening and integral mechanical attachment, or simply integral attachment. Mechanical joining involves the attachments of components in an assembly or elements in structure through the either an integral of the components or elements or use of the supplement device called a fastener, which resulting in integral mechanical attachment and mechanical fastening. Mechanical joining is used joining or install structure from details parts and structural elements. For the both manifestations of mechanical joining, load are transferred from one component or element to another strictly through the development of pu rely mechanical forces rising from the interlocking and resulting interferences or vice versa of two or more components or components and fasteners. There are no dependences on the development of any primarily or secondary atomic, ionic, or molecular bonds between the components materials. Mechanical is the components to fabricated from different materials to be joint, There is no has for chemical and physical interaction. If the interaction occurs when seen as problematic such as galvanic corrosion or galling and seizing during adhesive wear. Mechanical joining is used to create assemblies or structures from detailed parts or structural elements. Mechanical joining offers many advantages compare to other fundamental joining process. The first advantages of mechanical joining is this process unique in that is primarily dependent on the structures to be joined, and only dependent on the materials which these structures are composed. No bonds need to be formed to accomplish joining, nor do any need to be broken to accomplish disassembly. Where, mechanical joining methods or technique uniquely allow simple practical disassembly without damaging the parts involved. The second advantages is uniquely allows intentional disassembly without damaging parts involved. Where, this is very frequently essential for the purpose of portability, maintenance, services replacements, of damages parts, modification, of the assembly or structures. The third advantage is no bonds formed. Where, is the most form of mechanical fastening and some form of integral attachment permit relative intentional motion between joined parts. The fourth advantage i s mechanical joining may no changes to the chemical composition or microstructures the materials compare the parts being joined. Where, this is because the forces needed to hold the joint components together. And no atomic à ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬level bonding are created and no chemical interaction. The fifth advantage is this joining allows the different materials to be joined together such as metal to glass, and metal to polymers. The sixth advantage is provides a simple of achieving of structural damage tolerance beyond inherent material damage tolerance. Mechanical joining also has disadvantages such as, all mechanical joining fastening and integral attachment is that stress concentrates at the point of fastening or attachment. For example of fastener requiring hole is screw, key, bolt, rivet and pin. The hole can create the stress concentration unless the fastener is interference is specially process to create a compressive residual stress to offset tension stress. For other type is virtually all integral attachment, stress concentrates at the point of attachment. Stress concentration is particular concern in fatigue critical structure, but it can more aggravate accelerate corrosion. The second disadvantages of mechanical joining is mechanical joining related to above mentioned stress concentration is that the utility of mechanical joining. Stress concentration can lead to fastener hole or attachment feature distortion and loss of effectiveness. The utility of mechanical joining can be limited by materials anisotropy, particularly i f that anisotropy leads to weakness through the fastening thickness, as in most laminated composites. The result can be fastener pull through or pull out. The third disadvantages of mechanical joining can be the open nature of the joint between points of fastening, around fasteners and between points of attachment. Such as joint allows moisture, water, air, fluid intrusion, permits leaks, and can accelerate corrosion in the oxygen starved crevice and dissimilar electrochemical nature of the joined materials or any residual stresses. For example, the ever present stress concentration. Other disadvantage of mechanical fastening is more intensity for assembly can be high, especially for high performance system. There can also be a weight when compare to integrally attached as welding, brazing and soldering. The joining can loosen in service as a result of vibration. Most cost or other process can be higher for some integral attachment method. It also can experience loosening and disass embly from flexing especially during impact from dropping, or material stress relaxation. As stated earlier, most joint are critical element of assembly and structure. They can be the weakest links in some assemblies or structures, thereby being the most likely areas of an assembly and structure to fail. Therefore, joints demand careful design for all forms of joining, including mechanical fastening and integral attachment. The most important aspects of the design joints is identifying the sources and estimating the magnitudes and directions of applied internally generated loads. The sources of loads can be weight or force, example from snow, water, wind, or other parts of the structure. The forces from interacting structures, internal inertial forces, vibrations, transients, especially from startups, shutdowns, and faults, temperature changes or thermal excursions, fluid pressures, prime movers. The joint element is held together by shear in the fastener and the bearing force or stress in the joint elements created by the fastener. For example of fastener properly used f or bearing-type shear-loaded joints are nails, rivets, pins, and key. When these joint is operating properly, the frictional force developed precludes the fastener from having to carry and apply a bearing force by not allowing slip of the joint element. Bolt can be used for joining such as a rivet is used on occasion. Because of the mechanical fastener is a stress and develop a stress concentration in the joint element. Mechanical fastener also relative to one another help distribute loading and also to edge of the joint elements. Shear loaded types of joints and fasteners being described here, and for tension loaded types of joints and fasteners to be described in the next subsection. Bearing force is imposed by this type of fastener hole and plastic deformation of the material surrounding the hole on opposing structure elements. The bearing force also tear and slugs of material from the join element. This can occur under static loading and the situation can be even worse for dynam ic loading by impact fatigue. Mechanical joining is used to joining or install of structure from details parts and structural elements. For the both manifestations of mechanical joining, load are transferred from one component and also the element to another the development of purely mechanical forces and rising from the interlocking, and result can more components and fasteners. There are no dependences on the development of any primarily or secondary atomic, ionic, or molecular bonds between the components materials. Mechanical allows components fabricated from different materials to be joined, since there is no need for chemical or physical interaction. If the interaction occurs it is usually seen as problematic such as galvanic corrosion or galling and seizing during adhesive wear. The procedure for design shear loaded fastened joint is the allowable stress design procedure. This procedure can be more fasteners are assumed to carry on equal share of the applied force and load. This procedure also is only truly valid for joint that are composed of perfectly material, which is not real case and at least valid for joint containing multiple row of fasteners. This procedure is generally accepted and is perfectly safe when conservative allowable are used, such as the result of imprecise analysis. Shared loading also depend on all fastener being same size and material. Shared loading also has fitting with equal tightness in fastener hole. Empirical used to determine the maximum working stress that can be allowed in the fastener. Under the stress design procedure for bearing type shear loaded joints, the various elements of the joint such as including structural members and fasteners and must be sized so that the following conditions are satisfied, the fasteners can be not damage in shear by overload, the joint plate can be not damage in tension by overload, the fastener holes cannot be deformed by bearing loads from the fasteners, and the fasteners will not tear out of the joint plates at edges. These various modes of potential failure are shown schematically. None of these modes will occur if the appropriate allowable stresses are not exceeded in the fastener, for example shear. The advantage of the allowable stress design procedure is not precludes failure under any conditions such as although it does so under normal operating condition, but that it allows the designer to choose the mode by which the structure would ultimately damage. This procedure allows the designer to choose the low joining in the structure. The double-lap shear is composed of ASTM A36 steel, contain five 22 diameter ASTM A325 steel bolts arranged as shown although the specific pattern does not matter for symmetrical loading, the bolts have a thread pitch of 2mm per thread or, in the Unified system. Shear plates in the double lap joint the unthreaded portion and one passes through the threaded portion of each bolt. The problem is to determine the various stresses produced in the fastener and in the joint plates by a load of 300kN (67,000 lbs. force). The shear stress produced in a fastener given load depend on the actual cross sectional area of the fastener, and this is affected by whether the fastener is threaded and unthreaded in the region through which a shear plane in the joint elements passes. For example, the shear stress where F is the force in kilo Newtonà ¢Ãƒ ¢Ã¢â‚¬Å¡Ã‚ ¬Ãƒ ¢Ã¢â‚¬Å¾Ã‚ ¢s (or lbs. force), b is the number of shear planes that actually pass through the unthreaded fastener or portion of the shank of a fastener. Joint is critical elements of assemblies and structures. They can be weakest link in some assemblies or structures, thereby being the most likely areas of an assembly or structure to damage or low joining parts. Joints demand careful design for all forms of joining, including mechanical fastening or integral attachment. The most important aspects of the design of all joints is identifying the sources and estimating the magnitudes and directions of applied and internally generated loads. The loads also can be static, for example for steady or unchanging and dynamic in combination. The sources of loads can be weights or forces as from snow, water, wind, or other parts of the structure. The forces from interacting structures, internal inertial forces, vibrations, and transients especially from startup, shutdown, and the temperature can be changes in thermal excursions, fluid pressures, prime movers. The joint element is shear in the fastener and the bearing force. Stress also created by the fastener. The examples of fasteners properly used for bearing type shear loaded joints such as nails, rivets, pins, and keys . In friction shear loaded joints, the fasteners must create a significant amount of clamping force on the joint, holding the joint elements together and prevent any motion and slip. The resulting friction created between the joint and the result of their coefficient of friction and applied normal force. When these joints are operating properly, the frictional force developed precludes the fastener from having to carry and apply a bearing force by not allowing slip of the joint elements. Only bolts can be properly used for such joints, certain rivets are used on occasion. The shear stress in bearing type connections is related to the arrangement of the pieces or structural elements comprising the joint. The advantages of single-laps are ease of assembly and cost, and the advantages of double laps are elimination of eccentric loading and reduction of shear stresses at each of the multiple shear planes in the fastener in bearing type joints. Finally, the designer must ensure that fasteners will not tear out of the joint plate. This can only occur if the fasteners are located so close to the edge of the plate that the shear stress developed by bearing exceeds the ability of the plate material to sustain that stress over all shear planes from the fasteners to the edge. In fact, tear out cannot occur if there are multiple rows of fasteners, given sharing of load by all fasteners. This is because a slug of material near the edge could not tear out if the strain to elongation at the fastener holes, because by bearing did not exceed the strain needed to cause shear overload over all the aforementioned planes. In this illustrative example there are multiple rows of fasteners, so tear out could not occur and the holes on the second and third rows from the edge would have to elongate in bearing by enough to cause tear out of slugs between the first row and the edge. If there were three bolts in a row, there would be six shear planes such as on areas to cause tear out. For friction joint, the design analysis is slightly different than for bearing type joint. Friction joint also the intent to have an appropriate fastener, for example a bolt or machine screw or, sand rivet to apply a clamping load high enough to cause sufficient frictional force to applied the load, The fastener is protect from ever having to carry shear or cause bearing. The necessary slip resistances, as the frictional force to apply in this way is called, depend on greatly of the surface conditions of the structural joint element materials at their joint faying interface. Typical slip coefficients of friction can be found. V alues can be seen to be highly dependent on the treatment and condition of the joint surfaces, which must be carefully stipulated and controlled for such friction-type joints to work reliably. For example, surfaces cannot be painted unless painting is called for and an approved paint is used. No lubricants can ever be used if not planned for at the design stage. One even needs to worry about water infiltration in such joints, since water acts as a lubricant and drastically lowers the slip coefficient of a joint consider being dry during operational service. The ultimate strength of a friction type joint is considered to be the low of resistance or bearing strength. The bearing strength is more strong by using the same equations as in IE 2.2, except that one would enter the related stress for each material used in the joint plates and fasteners and apply the force that would be required to produce a stress to cause shear overload in the fasteners, tensile overload in joint plates, el ongation such as in bearing overload and can be fastener holes in every part joint plates, or fastener tear-out from the joint plate near its edge. The low force is then compared the force to cause slip because to earlier for an assumed value of average fastener joint preload. The lower of these determines the ultimate load-carrying capacity of the friction-type joint. Mechanical allows components fabricated from different materials to be joined, since there is no need for chemical or physical interaction. If the interaction occurs it is usually seen as problematic such as galvanic corrosion or galling and seizing during adhesive wear. Mechanical joining is used to create assemblies or structures from detailed parts or structural elements. Mechanical joining, load are transferred from one component or element to another strictly through the development of purely mechanical forces rising from the interlocking and resulting interferences or vice versa of two or more components or components and fasteners. There are no dependences on the development of any primarily or secondary bonds between the components materials. Mechanical joining is actually processing in a locking feature plastic deformation. Such joints can only be employed with materials that exhibit plastic deformation, yet still retain their strength or mechanical integrity. Ductile metals and thermoplastic polymers are the two example such as formed in folded tabs, crimps, hems, and punched stakes are good example in metals, and crimps, hems, and punched or heat set stakes are example in thermoplastic polymers. Mechanical joining is allows parts to assemb ly to move relative to one another to provide needed system functionality, while maintaining part arrangement, proximity, and orientation. The process causes no chemical and microstructure will be changes in the material being joined, so dissimilar types can be combine easily, and all can be intentionally disassembled to allow maintenance, service, repair, upgrade, ultimate disposal, or portability The joining parts assemblies and a structure element is joining in structures mechanical joining, which involves two major subclasses of mechanical fastening and integral in mechanical attachment. Mechanical joining is to attachment of components in an assembly to use of either an integral feature is used the part to install the supplemental device called a fastener resulting in integral mechanical attachment and mechanical fastening, respectively. Mechanical joining is a load to transfer from one parts or element to another strictly and the development of purely mechanical forces arising from the interlocking and resulting interference of two or more components, or component and fastener. Mechanical is the components to fabricated from different materials to be joint, There is no has for chemical and physical interaction. If the interaction occurs when seen as problematic such as galvanic corrosion or galling and seizing during adhesive wear. Mechanical joining is used to create assemblies or structures from detailed parts or structural elements.Mechanical joining has been critical to engineering such as in manufacturing, structure, and also in construction. Mechanical joining is very important because the result more fastener from other process. Mechanical joining has more advantages. The detailed methods by which mechanical joining is accomplished have expanded, the number of joints produced continues to grow, and the performance demands and expectations are becoming greater.

Faith-Based Social Service Organization Essay

Habitat for Humanity does not give away free homes to anyone. Habitat for Humanity provides housing that families can afford. Every family that receives a home puts in as much work as a volunteer and they contribute 300 to 500 hours of â€Å"sweat equity† on the construction of their home or someone else’s home, as their website states. The website states there are a lot of myths about Habitat for Humanity. People assume families receive completely free homes, when in fact this is not true. A lot of hard work goes into building these homes and all of the future home owners put in an equal amount of hard work. Habitat for Humanity receives many donations for a new home and provides the family with an affordable mortgage. Habitat for Humanity states â€Å"Habitat for Humanity offers homeownership opportunities to families who are unable to obtain conventional house financing. Generally, this includes those whose income is 30 to 50 percent of the area’s median income. In most cases, prospective Habitat homeowner families make a $500 down payment. † Habitat for Humanity is a Christian based organization, but does not discriminate against religion. Habitat for Humanity provides homes for families of any religion, race, or any other difference. Habitat for Humanity also provides faith in communities and in stows Christian beliefs into families of need. Habitat for Humanity states â€Å"Habitat’s ministry is based on the conviction that to follow the teachings of Jesus Christ, we must love and care for one another. Our love must not be words only— it must be true love, which shows itself in action. Habitat provides an opportunity for people to put their faith and love into action. We bring diverse groups of people together to make affordable housing and better communities a reality for everyone. Habitat for Humanity has a strong Christian background; however, they accept anyone that believes in providing help for others. Habitat for Humanity also receives government funding to help families in need of homes. They accept donations from the government, but do not accept donations if it affects their Christian beliefs. Habitat for Humanity states â€Å"Habitat is an independent, nonprofit organization that accep ts some government funds and other resources to help provide houses for those in need. We accept these funds as long as they do not limit our ability to demonstrate the love and teachings of Jesus Christ. Additionally, our local affiliates insert specific guidelines as needed to avoid becoming dependent on or controlled by government funds. † I found this statement to show how strongly faith-based this organization is. Habitat for Humanity is a very excellent organization and provides people with much more than just a home. They give families faith in their futures and provide a sense of stability for a family. I believe Habitat for Humanity has volunteers who are knowledgeable about the organization’s beliefs. I believe the lucky families also know about Habitat for Humanity’s beliefs and views of Christianity.

Analyzing Hezbollah And Its Use Of Violence Against Israel

Brianna Yannie Cho Islam and Politics Final Paper Strategic Hezbollah: Analyzing Hezbollah and Its Use of Violence Against Israel Introduction In the 1980s, Lebanon’s Hezbollah declared, â€Å"Israel is a rapist enemy that we will continue to fight until the raped land is returned to its rightful owners†, and subsequently initiated a militaristic and political struggle, as some would deem â€Å"terrorist† in nature, that would begin in approximately 1982 and persist to this very day.1 After having claimed thousands of lives, and eventually cleared Lebanon of Israeli occupation, this struggle has been, and still is subject of much scholarly attention. Much of the literature surrounding this topic has specifically dealt with the shifts in Hezbollah’s ideology and its incorporation of political Islam. Slightly diverging from previous areas of scholarly research and analysis, this paper will, from a political economy perspective, drawing facts from history, assess Hezbollah’s strategic use of violence in its resistance against Israel, precisely during the period from 1982 to 2000.2 In this paper, I argue that Hezbollah was able to achieve its goals of resistance against Israeli occupation in south Lebanon, because of its ability to secure a strategic relationship with a patron, and arouse and maintain popular local support through Islam and common identities. But more importantly, I aim to highlight that the organization was able to achieve its goals because of its strategic use ofShow MoreRelatedThe Strategic Logic of Suicide Terrorism by Pape, Bloom, and Horowitz 1429 Words   |  6 Pagesâ€Å"Terrorism involves the use of violence by an organization other than a national government to cause intimidation or fear among a target audience;† at least, this is how Pape (2003) defines terrorism in his article â€Å"The Strategic Logic of Suicide Terrorism† (343). The goal of this article by Pape is to discuss suicide terrorism and how it â€Å"follows a strategic logic, one specifically designed to coerce modern liberal democracies to make significant territorial concessions† (343). Similar to Pape,Read MoreEvolution Of The Islami c State8537 Words   |  35 PagesAfghan Taliban. To properly analyze these factors of development, relevant theoretical framework will be highlighted including insurgent cohesion and development, alliance formation in civil wars and the factors determining levels of insurgent violence. Second, a comparative study of the previously mentioned organizations will be utilized to cross-examine ISIS’ composition and behavior. Similarities and differences in organizational structure and methodology between the case studies will be correlatedRead MoreMedia Propaganda9887 Words   |  40 Pagesto impartially providing information, propaganda, in its most basic sense, presents information primarily to influence an audience. Propaganda often presents facts selectively (thus possibly lying by omission) to encourage a particular synthesis, or uses loaded messages to produce an emotional rather than rational response to the information presented. The desired result is a change of the attitude toward the subject in the target audience to further a political agenda. Propaganda can be used as aRead MoreGp Essay Mainpoints24643 Words   |  99 Pagesjournalists closer to their subject matter than professional journalists †¢ Better position to uncover unique on-the-ground perspectives Mainstream GOOD: Sheer physical authenticity - reliability †¢ Cost of publishing book acts as a barrier to entry against casual writers †¢ Hardly any oversight over the quality of material that gets published via new media channels †¢ Any work, regardless of its value, can easily get broadcasted to a global audience †¢ Publishers want to ensure that their books

Trying to Buy a Fixer-Upper Home The Government Can Help

Homebuyers looking for a â€Å"fixer-upper† loan for a house in need of repair or to finance needed maintenance to their current home often find themselves in a quandary: They cant borrow the money to buy a house because the bank wont make the loan until the repairs are done, and the repairs cant be done until the house has been purchased. The Department of Housing and Urban Development (HUD) offers two loan programs that can make the dream of rehabbing a fixer-upper a reality: the Federal Housing Administrations 203(k) mortgage and Fannie Maes HomeStyle Renovation mortgage. The 203(k) Program HUDs 203(k) program can allow a buyer to purchase or refinance a property plus include in the loan the cost of making repairs and improvements. The Federal Housing Administration (FHA)-insured 203(k) loan is provided through approved mortgage lenders nationwide. It is available to persons wanting to occupy the home. The down  payment requirement for an owner-occupant (or a nonprofit organization or government agency) is approximately 3 percent of the acquisition and repair costs of the property. Renovations arent limited to rot and decay. They can include buying new appliances, painting or replacing outdated flooring. Requirements Minimum credit score of 580 (Or 500 with 10% down payment)Minimum 3.5% down payment.Primary residences only How the Program Works The HUD 203(k) loan involves the following steps: A potential homebuyer locates a fixer-upper and executes a sales contract after doing a feasibility analysis of the property with their real estate agent. The contract should state that the buyer is seeking a 203(k) loan and that the contract is contingent on loan approval based on additional required repairs by the FHA or the lender.The homebuyer then selects an FHA-approved 203(k) lender and arranges for a detailed proposal showing the scope of work, including a detailed cost estimate on each repair or improvement of the project.The appraisal is performed to determine the value of the property after renovation.If the borrower passes the lenders credit-worthiness test, the loan closes for an amount that will cover the purchase or refinance cost of the property, the remodeling costs, and the allowable closing costs. The amount of the loan will also include a contingency reserve of 10% to 20% of the total remodeling costs and is used to cover any extra work not included in the origina l proposal.At closing, the seller of the property is paid off and the remaining funds are put in an escrow account to pay for the repairs and improvements during the rehabilitation period.The mortgage payments and remodeling begin after the loan closes. The borrower can decide to have up to six mortgage payments (PITI) put into the cost of rehabilitation if the property is not going to be occupied during construction, but it cannot exceed the length of time it is estimated to complete the rehab. (PITI stands for principal, interest, taxes, and insurance.)Funds held in escrow are released to the contractor during construction through a series of draw requests for completed work. To ensure completion of the job, 10% of each draw is held back; this money is paid after the lender determines there will be no liens on the property.Private Mortgage Insurance (PMI) is required, but unlike conventional loans, it is not removed once equity in the property reaches 20%. For a list of lenders who are offering the 203(k) Rehabilitation Program, see HUDs 203(k) Lenders List. The interest rate and discount points on the loan are negotiable between the borrower and the lender. Fannie Mae HomeStyle Renovation Mortgage The HomeStyle Renovation mortgage through Fannie Mae provides a convenient and flexible way for borrowers considering home improvements to make repairs and renovations with  a first mortgage, rather than a second mortgage, home equity line of credit, or other more costly methods of financing. Eligible Properties The HomeStyle mortgage can be used to buy: Principal residences, from one to four unitsOne-unit second homes (granny units)Single-unit investment properties (co-ops, condos) Types of renovations mortgages include 15- and 30-year fixed-rate mortgages and Adjustable-Rate Mortgages (ARMs). Fannie Mae notes that â€Å"The original principal amount of the mortgage may not exceed Fannie Mae’s maximum allowable mortgage amount for a conventional first mortgage.† Down Payments While the average Fannie Mae HomeStyle loan’s minimum down payment is around 5%, there are no specific minimum down payment stipulations. Instead, HomeStyle lenders use factors including the home’s equity and borrower’s credit rating to determine the cost of the loan.   HomeStyle mortgages are unique in that Fannie Mae based them on the â€Å"as completed† value of the home after repairs and upgrades have been made. As a result, the homebuyer is assured that all costs of renovations will be covered by the mortgage. Also, money for improvements is not released until the work has been completed and approved by an FHA-certified inspector. There is no need for â€Å"sweat equity.† What’s Included? The HomeStyle mortgage offers a generous range of costs for inclusion in the loan including: Architects or designers expensesEnergy efficiency assessmentsEngineering and design updatesRequired inspectionsPermit fees All work must be completed promptly by lender-approved, licensed and certified contractors and architects. All repairs made using this type of loan must be permanently affixed to the property.